Insulating film and preparation method and application thereof

Abstract

The invention relates to an insulating film and a preparation method and application thereof, and belongs to the technical field of energy storage devices. The insulating film comprises a base material and a bonding layer and a polymer layer which are sequentially arranged on at least one surface of the base material in a stacked mode, the base material contains heat-resistant resin, the heat-resistant resin comprises one or more of poly (1, 4-cyclohexylenedimethylene terephthalate), polyimide and polyetherimide, and the bonding layer and the polymer layer are sequentially arranged on at least one surface of the base material in a stacked mode. The polymer in the polymer layer comprises one or more of polyethylene, polypropylene and polycarbonate. Therefore, the anti-puncture strength and the anti-aging performance of the insulating film are effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage devices, and in particular to an insulating film and a preparation method and application thereof. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] In order to meet the insulation requirements of the battery, an insulating film is usually wrapped on the outer surface of the battery to ensure the insulation of the battery from the surrounding environment. However, the puncture resistance and aging resistance of the traditional insulating film are poor. The battery is subject to vibration during use, and other components around the insulating film may wear through the insulating film. Summary of the invention

[0004] Based on this, the present application provides an insulating film and a preparation method and application thereof, aiming to improve the puncture resistance and aging resistance of the insulating film.

[0005] In a first aspect of the present application, an insulating film is provided, comprising a substrate and an adhesive layer and a polymer layer sequentially stacked on at least one surface of the substrate, wherein the substrate contains a heat-resistant resin, the heat-resistant resin includes one or more of poly(1,4-cyclohexanedimethanol terephthalate), polyimide and polyetherimide, and the polymer in the polymer layer includes one or more of polyethylene, polypropylene and polycarbonate.

[0006] In the above-mentioned insulating film, poly(1,4-cyclohexanedimethanol terephthalate), polyimide and polyetherimide in the substrate have excellent heat resistance, tensile strength and stable structure; the polyethylene, polypropylene and polycarbonate in the polymer layer have good flexibility, tensile strength and wear resistance, and the polymer layer can isolate water vapor and reduce the risk of aging and hydrolysis of the substrate; the combination of various materials in the substrate and various materials in the polymer layer improves the puncture resistance and aging resistance of the insulating film.

[0007] In some embodiments, the tensile strength of the insulating film is ≥150 MPa.

[0008] In some embodiments, the puncture resistance of the insulating film is ≥50N.

[0009] In some embodiments, based on the mass of the substrate, the mass fraction of the heat-resistant resin is 90% to 100%, and may be 90% to 95%.

[0010] In some embodiments, based on the mass of the polymer layer, the mass fraction of the polymer is 99.5% to 100%, and optionally 99.5% to 99.8%.

[0011] In some embodiments, the heat-resistant resin includes poly(1,4-cyclohexanedimethylene terephthalate), and the polymer includes polyethylene.

[0012] In some embodiments, the polyethylene is high density polyethylene.

[0013] In some embodiments, the substrate further comprises a chain extender, and the chain extender includes an aliphatic diol chain extender and a diamine chain extender.

[0014] In some embodiments, based on the mass of the substrate, the mass fraction of the chain extender is 1% to 10%, and optionally 5% to 10%.

[0015] In some embodiments, the aliphatic diol chain extender includes one or more of ethylene glycol, 1,4-butanediol, hydroquinone dihydroxyethyl ether, and resorcinol dihydroxyethyl ether.

[0016] In some embodiments, the diamine chain extender includes an aromatic diamine chain extender and an aliphatic diamine chain extender.

[0017] In some embodiments, the aromatic diamine chain extender includes one or more of 3,3-dichloro-4,4-diaminophenylmethane, diethyltoluenediamine, 4,4-methylene-bis(3-chloro-2,6-diethylaniline) and bis-sec-butylaminodiphenylmethane.

[0018] In some embodiments, the aliphatic diamine chain extender includes isophorone diamine.

[0019] In some embodiments, the polymer layer further comprises a β-nucleating agent.

[0020] In some embodiments, based on the mass of the polymer layer, the mass fraction of the β-nucleating agent is 0.2% to 0.5%.

[0021] In some embodiments, the β-nucleating agent includes one or more of a sorbitol derivative nucleating agent, a carboxylic acid metal salt nucleating agent, an organic phosphate nucleating agent, and a rosin acid salt nucleating agent.

[0022] In some embodiments, the thickness of the substrate accounts for 40% to 60% of the thickness of the insulating film.

[0023] In some embodiments, the thickness of the polymer layer accounts for 20% to 38% of the thickness of the insulating film.

[0024] In some embodiments, the thickness of the adhesive layer accounts for 10% to 30% of the thickness of the insulating film.

[0025] In some embodiments, the thickness of the substrate is 80 μm to 120 μm.

[0026] In some embodiments, the single-side thickness of the polymer layer is 30 μm to 40 μm.

[0027] In some embodiments, the thickness of a single side of the adhesive layer is 10 μm to 20 μm.

[0028] In some embodiments, the adhesive layer comprises one or more of acrylic pressure-sensitive adhesive, vinyl acetate copolymer, polyurethane, polyvinyl chloride and silicone adhesive.

[0029] A second aspect of the present application provides a method for preparing the insulating film according to the first aspect of the present application, comprising the following steps:

[0030] Disposing the adhesive layer on at least one surface of the substrate;

[0031] The polymer layer is disposed on a surface of the adhesive layer remote from the substrate.

[0032] The above preparation method can simply prepare the insulating film, which is conducive to the mass production of the insulating film.

[0033] In some embodiments, the tensile strength of the substrate is 140 MPa to 190 MPa.

[0034] In some embodiments, the polymer layer has a tensile strength of 60 MPa to 110 MPa.

[0035] A third aspect of the present application provides a battery, comprising at least one of the insulating film described in the first aspect of the present application and the insulating film prepared by the preparation method described in the second aspect of the present application.

[0036] The battery of the present application includes the insulating film provided in the present application and / or the insulating film produced by the preparation method provided in the present application, and thus has at least the same advantages as the insulating film and / or the insulating film produced by the preparation method.

[0037] The fourth aspect of the present application provides an electrical device, comprising at least one of the insulating film described in the first aspect of the present application, the insulating film prepared by the preparation method described in the second aspect of the present application, and the battery described in the third aspect of the present application.

[0038] The electrical device of the present application includes at least one of the insulating film provided in the present application, the insulating film obtained by the preparation method provided in the present application, and the battery provided in the present application, and thus has at least the same advantages as the insulating film, the insulating film obtained by the preparation method, and at least one of the batteries.

[0039] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to better describe and illustrate the embodiments or examples provided by the present application, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of the disclosed application, the embodiments or examples currently described, and any of the best modes of these applications currently understood. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0041] Figure 1 It is a schematic diagram of a battery cell according to an embodiment of the present application.

[0042] Figure 2 for Figure 1 An exploded view of a battery cell according to an embodiment of the present application is shown.

[0043] Figure 3 It is a schematic diagram of a battery module according to one embodiment of the present application.

[0044] Figure 4 A schematic diagram of a battery pack according to an embodiment of the present application.

[0045] Figure 5 for Figure 4 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0046] Figure 6 FIG. 1 is a schematic diagram of an electrical device using a secondary battery according to an embodiment of the present application as a power source.

[0047] Description of reference numerals:

[0048] 1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 battery cell; 51 shell; 52 electrode assembly; 53 cover plate; 6 electrical device. DETAILED DESCRIPTION

[0049] Hereinafter, some embodiments of the insulating film, preparation method and application thereof of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0050] "Scope" disclosed in the present application can be limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or excluding end values, and any end value can be included or not included independently, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 listed, and if the maximum range values ​​3,4 and 5 are also listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation for these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to listing the parameter as, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0051] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0052] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0053] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments. The "implementation methods" mentioned herein have a similar understanding.

[0054] Those skilled in the art will appreciate that, in the methods of each embodiment or example, the order in which each step is written does not mean a strict order of execution and does not constitute any limitation on the implementation process, and the detailed order of execution of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0055] In the present application, in the open technical features or technical solutions described by the words "contain", "include", "comprise", etc., unless otherwise specified, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3. Unless otherwise specified, it may also include other members or may not include additional members. It can be regarded as providing both the feature or solution of "A consists of a1, a2 and a3" and the feature or solution of "A not only includes a1, a2 and a3, but also includes other members". In the present application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0056] In this application, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel schemes of "yes" or "no". If there are multiple "options" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "option" is independent.

[0057] Secondary batteries are widely used in electric vehicles and consumer electronic products due to their outstanding features such as light weight, no pollution, and no memory effect. The rapid development of secondary batteries has also put forward higher requirements for their safety performance. In order to make the battery meet the insulation requirements, an insulating film is usually wrapped on the outside of the battery to insulate the battery from the surrounding environment. For example, an insulating film is set between the battery and the water-cooling plate to insulate the battery and the water-cooling plate. However, in actual use, due to the poor puncture resistance and aging resistance of traditional insulating films, the protrusions on the surface of the water-cooling plate may wear through the insulating film.

[0058] Based on the above technical problems, the present application provides an insulating film, which includes a substrate and an adhesive layer and a polymer layer sequentially stacked on at least one surface of the substrate, the substrate contains a heat-resistant resin, the heat-resistant resin includes one or more of poly(1,4-cyclohexanedimethanol terephthalate), polyimide and polyetherimide, and the polymer in the polymer layer includes one or more of polyethylene, polypropylene and polycarbonate; the poly(1,4-cyclohexanedimethanol terephthalate), polyimide and polyetherimide in the substrate have excellent heat resistance, tensile strength and stable structure, the polyethylene, polypropylene and polycarbonate in the polymer layer have good flexibility, tensile strength and wear resistance, and the polymer layer can isolate water vapor and reduce the risk of aging and hydrolysis of the substrate; the combination of various materials in the substrate and various materials in the polymer layer improves the puncture resistance and aging resistance of the insulating film.

[0059] Insulation film

[0060] One embodiment of the present application provides an insulating film, including a substrate and an adhesive layer and a polymer layer sequentially stacked on at least one surface of the substrate, the substrate contains a heat-resistant resin, the heat-resistant resin includes one or more of poly(1,4-cyclohexanedimethanol terephthalate) (PCT), polyimide (PI) and polyetherimide (PEI), and the polymer in the polymer layer includes one or more of polyethylene (PE), polypropylene (PP) and polycarbonate (PC).

[0061] In the above embodiment, the poly(1,4-cyclohexanedimethanol terephthalate), polyimide and polyetherimide in the substrate have excellent heat resistance, tensile strength and stable structure; the polyethylene, polypropylene and polycarbonate in the polymer layer have good flexibility, tensile strength and wear resistance, and the polymer layer can isolate water vapor and reduce the risk of aging and hydrolysis of the substrate; the combination of various materials in the substrate and various materials in the polymer layer improves the puncture resistance and aging resistance of the insulating film.

[0062] Alternatively, the material type of each layer in the insulating film may be analyzed using an infrared spectrum in combination with the crystallization temperature measured by a DSC (differential scanning calorimeter) test.

[0063] In some embodiments, the tensile strength of the insulating film is ≥ 150 MPa.

[0064] In some embodiments, the puncture resistance of the insulating film is ≥50N.

[0065] In some embodiments, the mass fraction of the heat-resistant resin is 90% to 100% based on the mass of the substrate. For example, it can be: 90%, 92%, 94%, 96%, 98%, 100%. The mass fraction of the heat-resistant resin within the above range is conducive to further improving the puncture resistance and aging resistance of the insulating film. Optionally, the mass fraction of the heat-resistant resin is 90% to 95% based on the mass of the substrate.

[0066] In some embodiments, based on the mass of the polymer layer, the mass fraction of the polymer is 99.5% to 100%. For example, it can be: 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 100%. The mass fraction of the polymer within the above range is conducive to further improving the puncture resistance and aging resistance of the insulating film. Optionally, based on the mass of the polymer layer, the mass fraction of the polymer is 99.5% to 99.8%.

[0067] In some embodiments, the heat-resistant resin includes poly(1,4-cyclohexane dimethanol terephthalate), and the polymer includes polyethylene. Poly(1,4-cyclohexane dimethanol terephthalate) has a relatively high content of methylene, good flexibility, and low cost, and polyethylene has good flexibility, ductility, and weather resistance. Therefore, the use of a substrate containing poly(1,4-cyclohexane dimethanol terephthalate) in combination with a polymer layer containing polyethylene can further improve the puncture resistance and aging resistance of the insulating film. Optionally, the polyethylene is high-density polyethylene.

[0068] In this application, high-density polyethylene refers to polyethylene with a density of 0.94 g / cm 3 ~0.96g / cm 3 of polyethylene.

[0069] In some embodiments, the substrate further comprises a chain extender, which includes aliphatic diol chain extenders and diamine chain extenders. The chain extender can increase the viscosity of the heat-resistant resin and further increase the heat resistance and puncture resistance of the substrate.

[0070] In some embodiments, the mass fraction of the chain extender is 1% to 10% based on the mass of the substrate. Controlling the mass fraction of the chain extender within the above range can further improve the heat resistance and puncture resistance of the substrate. It is understood that the mass fraction of the chain extender includes but is not limited to: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. Further, based on the mass of the substrate, the mass fraction of the chain extender is 5% to 10%.

[0071] In some embodiments, the aliphatic diol chain extender includes one or more of ethylene glycol (EG), 1,4-butanediol (BDO), hydroquinone dihydroxyethyl ether (HQEE), and resorcinol dihydroxyethyl ether (HER).

[0072] In some embodiments, the diamine chain extender includes an aromatic diamine chain extender and an aliphatic diamine chain extender. Optionally, the aromatic diamine chain extender includes one or more of 3,3-dichloro-4,4-diaminophenylmethane (MOCA), diethyltoluenediamine (DETDA), 4,4-methylene-bis(3-chloro-2,6-diethylaniline) (MCDEA) and di-sec-butylaminodiphenylmethane (MDBA). Optionally, the aliphatic diamine chain extender includes isophoronediamine (IPDA).

[0073] In some embodiments, the polymer layer further comprises a β-nucleating agent. The β-nucleating agent can improve the tensile strength, modulus, crystallization rate and dimensional stability of polyethylene, polypropylene and polycarbonate, thereby further improving the puncture resistance and aging resistance of the polymer layer. Optionally, the β-nucleating agent includes one or more of a sorbitol derivative nucleating agent, a carboxylic acid metal salt nucleating agent, an organic phosphate nucleating agent and a rosin acid salt nucleating agent.

[0074] In the present application, the β-nucleating agent, also known as the β-crystal nucleating agent, is a nucleating agent that can induce a polymer to form a β-crystal.

[0075] In some embodiments, the mass fraction of the beta nucleating agent is 0.2% to 0.5% based on the mass of the polymer layer. Controlling the mass fraction of the beta nucleating agent within the above range can further improve the tensile strength, modulus, crystallization rate and dimensional stability of polyethylene, polypropylene and polycarbonate, thereby further improving the puncture resistance and aging resistance of the insulating film.

[0076] In some embodiments, the thickness of the substrate accounts for 40% to 60% of the thickness of the insulating film. For example, it can be: 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%. Controlling the proportion of the thickness of the substrate in the insulating film to the above range is conducive to further improving the puncture resistance and aging resistance of the insulating film.

[0077] In some embodiments, the thickness of the polymer layer accounts for 20% to 38% of the thickness of the insulating film. For example, it can be: 20%, 22%, 24%, 26%, 28%, 30%, 33%, 35%, 38%. Controlling the proportion of the thickness of the polymer layer in the insulating film to the above range is conducive to further improving the puncture resistance and aging resistance of the insulating film.

[0078] In some embodiments, the thickness of the adhesive layer accounts for 10% to 30% of the thickness of the insulating film. For example, it can be: 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%. The thickness of the adhesive layer in the insulating film is within the above range, which is conducive to further improving the bonding force between the substrate and the polymer layer.

[0079] In some embodiments, the thickness of the substrate is 80 μm to 120 μm. Controlling the thickness of the substrate within the above range is conducive to further improving the puncture resistance and aging resistance of the insulating film. It is understood that the thickness of the substrate includes but is not limited to: 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm.

[0080] In some embodiments, the thickness of the polymer layer on one side is 30 μm to 40 μm. Controlling the thickness of the polymer layer within the above range is conducive to further improving the puncture resistance and aging resistance of the insulating film. It is understood that the thickness of the polymer layer on one side includes but is not limited to: 30 μm, 32 μm, 34 μm, 36 μm, 38 μm, 40 μm.

[0081] In some embodiments, the thickness of the adhesive layer on one side is 10 μm to 20 μm. The thickness of the adhesive layer within the above range is conducive to further improving the bonding force between the substrate and the polymer layer. It is understood that the thickness of the adhesive layer on one side includes but is not limited to: 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm.

[0082] In the present application, "single-sided thickness" refers to the thickness of the setting layer on one side of the substrate. For example, the single-sided thickness of the polymer layer refers to the thickness of the polymer layer on one side of the substrate, and the single-sided thickness of the adhesive layer refers to the thickness of the adhesive layer on one side of the substrate.

[0083] In some embodiments, the adhesive layer comprises one or more of acrylic pressure-sensitive adhesive, vinyl acetate copolymer, polyurethane, polyvinyl chloride and silicone-based adhesive.

[0084] Another embodiment of the present application provides a method for preparing the above insulating film, comprising the following steps:

[0085] providing an adhesive layer on at least one surface of the substrate;

[0086] A polymer layer is disposed on a surface of the adhesive layer remote from the substrate.

[0087] Thus, the insulating film can be prepared simply, which is beneficial to the mass production of the insulating film.

[0088] In some embodiments, the tensile strength of the substrate is 140 MPa to 190 MPa. The tensile strength of the substrate is within the above range, which can further improve the puncture resistance and aging resistance of the insulating film. It is understood that the tensile strength of the substrate includes but is not limited to: 140 MPa, 145 MPa, 150 MPa, 155 MPa, 160 MPa, 165 MPa, 170 MPa, 175 MPa, 180 MPa, 185 MPa, 190 MPa.

[0089] In some embodiments, the tensile strength of the polymer layer is 60 MPa to 110 MPa. The tensile strength of the polymer layer is within the above range, which can further improve the puncture resistance and aging resistance of the insulating film. It is understood that the tensile strength of the polymer layer includes but is not limited to: 60 MPa, 65 MPa, 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, 105 MPa, 110 MPa.

[0090] Still another embodiment of the present application provides a battery, comprising at least one of the above insulating film and the insulating film prepared by the above preparation method.

[0091] Still another embodiment of the present application provides an electrical device, comprising at least one of the above-mentioned insulating film, the insulating film obtained by the above-mentioned preparation method, and the above-mentioned battery.

[0092] In addition, the battery and the electric device of the present application will be described below with reference to the drawings as appropriate.

[0093] Typically, a battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator. During the battery charge and discharge process, active ions are embedded and removed back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0094] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0095] In some embodiments, the battery may include an outer packaging, which may be used to encapsulate the electrode assembly and the electrolyte.

[0096] In some embodiments, the outer packaging of the battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and further, non-limiting examples of plastic may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0097] The battery includes at least one battery cell. The battery may include one or more battery cells.

[0098] In this application, unless otherwise specified, "battery cell" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and further, generally speaking, at least includes a positive electrode sheet, a negative electrode sheet and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0099] The present application has no particular limitation on the shape of the battery cell, which may be cylindrical, square or any other shape. Figure 1 The battery cell 5 is a square structure as an example.

[0100] In some embodiments, reference Figure 2 , the outer packaging may include a shell 51 and a cover plate 53. Among them, the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to actual needs.

[0101] The battery may be a battery module 4 or a battery pack 1 .

[0102] The battery module includes at least one battery cell. The number of battery cells contained in the battery module can be one or more, and those skilled in the art can select a suitable number according to the application and capacity of the battery module.

[0103] Figure 3 4 is an example of a battery module. Figure 3 In the battery module 4, the plurality of battery cells 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.

[0104] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0105] In some embodiments, the battery modules described above may also be assembled into a battery pack. The number of battery modules contained in the battery pack may be one or more. Those skilled in the art may select a suitable number according to the application and capacity of the battery pack.

[0106] Figure 4 and Figure 5 1 is a battery pack 1 as an example. Figure 4 and Figure 5 , the battery pack 1 may include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 to form a closed space for accommodating the battery module 4. Multiple battery modules 4 can be arranged in the battery box in any manner. Optionally, the above-mentioned insulating film of the present application can be wrapped on the battery module 4, or be arranged between the battery module 4 and the upper box body 2, or be arranged between the battery module 4 and the lower box body 3. For example, the insulating film can be arranged on the side of the battery module 4. In some embodiments, a water-cooling plate is arranged between the lower box body 3 and the battery module 4, and the above-mentioned insulating film of the present application is arranged between the battery module 4 and the water-cooling plate.

[0107] In addition, the present application also provides an electrical device, which includes the battery provided in the present application. The battery can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto. Among them, the mobile device may be, for example, a mobile phone, a laptop computer, etc.; the electric vehicle may be, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc., but are not limited thereto.

[0108] As an electrical device, a battery can be selected according to its usage requirements.

[0109] Figure 6 The power consumption device 6 is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device's requirements for high power and high energy density of the battery, a battery pack or a battery module can be used.

[0110] As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is usually required to be light and thin, and a battery may be used as a power source.

[0111] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If the techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0112] Example 1

[0113] The preparation method of the insulating film is as follows:

[0114] (1) Preparation of substrate

[0115] Poly(1,4-cyclohexanedimethanol terephthalate) (PCT) plastic particles (diameter of about 3 mm, height of about 4 mm, manufacturer: Eastman, USA, model: GTX2001) were melt-extruded by a screw, and then stretched, compressed and pulled to prepare a substrate with a thickness of 100 μm.

[0116] (2) Preparation of polymer layer

[0117] Polyethylene plastic particles (diameter of about 3 mm, height of about 4 mm, molecular weight of 300,000, manufacturer: Dushanzi, model: 8008) were melt-extruded by a screw, and then stretched, compressed and pulled to prepare a polymer layer with a thickness of 30 μm.

[0118] (3) Preparation of adhesive layer

[0119] The polymer layer and the substrate are compressed under the action of traction and pressure rollers, and bonded together by acrylic pressure-sensitive adhesive (manufacturer: 3M, model: 55236, main component: acrylate) to form a whole insulating film, which is finally cut into a film material of a certain width and wound and collected to obtain an insulating film. In the insulating film, polymer layers are provided on both surfaces of the substrate in the thickness direction, and an adhesive layer is provided between the substrate and the polymer layer. The thickness of the adhesive layer is 10 μm, and the adhesive layer contains acrylate.

[0120] Example 2

[0121] The method is basically the same as Example 1, except that: the method for preparing the substrate in step (1) is changed;

[0122] The preparation method of the substrate in step (1) of this embodiment is as follows:

[0123] PCT plastic particles and ethylene glycol chain extender were mixed in a mass ratio of 99:1, melt-extruded by a screw, and then stretched, compressed and pulled to prepare a substrate with a thickness of 100 μm.

[0124] Example 3

[0125] The method is basically the same as Example 1, except that: the method for preparing the substrate in step (1) is changed;

[0126] The preparation method of the substrate in step (1) of this embodiment is as follows:

[0127] PCT plastic particles and ethylene glycol chain extender were mixed in a mass ratio of 97:3, and after melt extrusion by a screw, a substrate with a thickness of 100 μm was prepared by stretching, compression and traction.

[0128] Example 4

[0129] The method is basically the same as Example 1, except that: the method for preparing the substrate in step (1) is changed;

[0130] The preparation method of the substrate in step (1) of this embodiment is as follows:

[0131] PCT plastic particles and ethylene glycol chain extender were mixed in a mass ratio of 95:5, and after melt extrusion by a screw, a substrate with a thickness of 100 μm was prepared by stretching, compression and traction.

[0132] Example 5

[0133] The method is basically the same as Example 1, except that: the method for preparing the substrate in step (1) is changed;

[0134] The preparation method of the substrate in step (1) of this embodiment is as follows:

[0135] PCT plastic particles and ethylene glycol chain extender were mixed in a mass ratio of 90:10, melt-extruded by a screw, and then stretched, compressed and pulled to prepare a substrate with a thickness of 100 μm.

[0136] Embodiment 6-7

[0137] The method is basically the same as Example 1, except that: the preparation parameters of the substrate in step (1) are changed;

[0138] The heat-resistant resin in the substrate of Example 6 is polyimide (PI), whose manufacturer is Mitsui Chemicals and whose model is PL450A;

[0139] The heat-resistant resin in the substrate of Example 7 is polyetherimide (PEI), the manufacturer of which is Sabic, and the model number is 1010R-7101.

[0140] Example 8

[0141] The method is basically the same as Example 1, except that: the preparation method of the polymer layer in step (2) is changed;

[0142] The preparation method of the polymer layer in step (2) of this embodiment is as follows:

[0143] Polyethylene plastic particles and a sorbitol derivative nucleating agent (manufacturer: Milliken, model: 3988) were mixed in a mass ratio of 99.65:0.35, and after melt extrusion by a screw, a polymer layer with a thickness of 30 μm was prepared by stretching, compression and traction.

[0144] Example 9

[0145] The method is basically the same as Example 1, except that: the preparation method of the polymer layer in step (2) is changed;

[0146] The preparation method of the polymer layer in step (2) of this embodiment is as follows:

[0147] Polyethylene plastic particles and a sorbitol derivative nucleating agent (manufacturer: Milliken, model: 3988) were mixed in a mass ratio of 99.80:0.20, and after melt extrusion by a screw, a polymer layer with a thickness of 30 μm was prepared by stretching, compression and traction.

[0148] Example 10

[0149] The method is basically the same as Example 1, except that: the preparation method of the polymer layer in step (2) is changed;

[0150] The preparation method of the polymer layer in step (2) of this embodiment is as follows:

[0151] Polyethylene plastic particles and a sorbitol derivative nucleating agent (manufacturer: Milliken, model: 3988) were mixed in a mass ratio of 99.50:0.50, and after melt extrusion by a screw, a polymer layer with a thickness of 30 μm was prepared by stretching, compression and traction.

[0152] Examples 11-16

[0153] The method is basically the same as Example 1, except that the preparation parameters of step (1) the substrate layer, step (2) the polymer layer, and step (3) the adhesive layer are changed;

[0154] The manufacturer of the polypropylene (PP) in the polymer layer of Example 11 is Dushanzi, and the model number is 8003;

[0155] The manufacturer of the polycarbonate (PC) in the polymer layer of Example 12 is Lotte, and the model number is 1100;

[0156] The polyurethane double-sided adhesive in the adhesive layer of Example 15 is manufactured by Tesa, with a model number of Tesa67215;

[0157] The epoxy resin double-sided tape in the adhesive layer of Example 16 is produced by 3M and its model number is 10#.

[0158] Comparative Example 1

[0159] The method is basically the same as Example 1, except that: the preparation parameters of the substrate in step (1) are changed;

[0160] In this comparative example, the heat-resistant resin in the substrate is polyethylene terephthalate (PET), the manufacturer of PET is Shanghai Yuanfang, and the model is CB 602.

[0161] Comparative Example 2

[0162] The embodiment is basically the same as the first embodiment, except that no polymer layer and no adhesive layer are provided in the insulating film.

[0163] The product parameters of Examples 1-16 and Comparative Examples 1-2 are shown in Tables 1 to 3.

[0164] Table 1

[0165]

[0166]

[0167] Table 2

[0168]

[0169] Table 3

[0170]

[0171]

[0172] Performance Testing

[0173] (1) Puncture resistance

[0174] The puncture resistance of the insulating film is tested according to the test standard GB / T 37841-2019. Specifically, the insulating film sample is fixed between the clamping rings, and the puncture needle vertically pierces the center of the sample at a certain rate, and the load borne by the sample during puncture is recorded to obtain the puncture resistance, that is, the puncture strength.

[0175] (2) Tensile strength

[0176] The test standard is ASTM D882 / GB / T 1040. Standard samples are made according to the test standard, and the tensile strength of the polymer layer, substrate and insulating film are tested respectively using a universal testing machine.

[0177] (3) Aging resistance

[0178] After the insulating film was aged for 1000 hours at 85°C and 85%RH, the retention rates of tensile strength and elongation at break were tested according to ISO 527-2. Retention rate of elongation at break (%) = length of the insulating film after aging when it was broken / length of the insulating film before aging before stretching × 100%.

[0179] The performance test results of the products of Examples 1-16 and Comparative Examples 1-2 are shown in Table 4.

[0180] Table 4

[0181]

[0182]

[0183] It can be seen from Tables 1 to 4 that, compared with the insulating films of Comparative Examples 1-2, the insulating films of Examples 1-16 have better puncture resistance and aging resistance, indicating that the combination of various materials in the substrate and various materials in the polymer layer of the insulating films of Examples 1-16 effectively improves the puncture resistance and aging resistance of the insulating films.

[0184] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0185] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An insulating film, characterized in that: The invention comprises a substrate and an adhesive layer and a polymer layer which are sequentially stacked on at least one surface of the substrate, wherein the substrate contains a heat-resistant resin, the heat-resistant resin comprises one or more of poly(1,4-cyclohexanedimethanol terephthalate), polyimide and polyetherimide, and the polymer in the polymer layer comprises one or more of polyethylene, polypropylene and polycarbonate.

2. The insulating film according to claim 1, wherein The insulating film has one or more of the following features: (1) The tensile strength of the insulating film is ≥150 MPa; (2) The puncture resistance of the insulating film is ≥50N.

3. The insulating film according to claim 1, wherein Based on the mass of the substrate, the mass fraction of the heat-resistant resin is 90% to 100%, and can be optionally 90% to 95%.

4. The insulating film according to claim 1, wherein Based on the mass of the polymer layer, the mass fraction of the polymer is 99.5% to 100%, and optionally 99.5% to 99.8%.

5. The insulating film according to claim 1, wherein The heat-resistant resin includes poly(1,4-cyclohexanedimethanol terephthalate), and the polymer includes polyethylene; Optionally, the polyethylene is high-density polyethylene.

6. The insulating film according to any one of claims 1 to 5, characterized in that: The substrate further comprises a chain extender, and the chain extender comprises an aliphatic diol chain extender and a diamine chain extender; Optionally, based on the mass of the substrate, the mass fraction of the chain extender is 1% to 10%, and further optionally 5% to 10%; Optionally, the aliphatic diol chain extender includes one or more of ethylene glycol, 1,4-butanediol, hydroquinone dihydroxyethyl ether and resorcinol dihydroxyethyl ether; Optionally, the diamine chain extender includes an aromatic diamine chain extender and an aliphatic diamine chain extender; further optionally, the aromatic diamine chain extender includes one or more of 3,3-dichloro-4,4-diaminophenylmethane, diethyltoluenediamine, 4,4-methylene-bis(3-chloro-2,6-diethylaniline) and bis-sec-butylaminodiphenylmethane; further optionally, the aliphatic diamine chain extender includes isophoronediamine.

7. The insulating film according to any one of claims 1 to 5, characterized in that: The polymer layer further comprises a β-nucleating agent; Optionally, based on the mass of the polymer layer, the mass fraction of the β-nucleating agent is 0.2% to 0.5%; Optionally, the β-nucleating agent includes one or more of a sorbitol derivative nucleating agent, a carboxylic acid metal salt nucleating agent, an organic phosphate nucleating agent and a rosin acid salt nucleating agent.

8. The insulating film according to any one of claims 1 to 5, characterized in that: The insulating film has one or more of the following features: (1) The thickness of the substrate accounts for 40% to 60% of the thickness of the insulating film; (2) The thickness of the polymer layer accounts for 20% to 38% of the thickness of the insulating film; (3) The thickness of the adhesive layer accounts for 10% to 30% of the thickness of the insulating film.

9. The insulating film according to any one of claims 1 to 5, characterized in that: The insulating film has one or more of the following features: (1) The thickness of the substrate is 80 μm to 120 μm; (2) The single-side thickness of the polymer layer is 30 μm to 40 μm; (3) The thickness of one side of the adhesive layer is 10 μm to 20 μm.

10. The insulating film according to any one of claims 1 to 5, characterized in that The adhesive layer contains one or more of acrylic pressure-sensitive adhesive, vinyl acetate copolymer, polyurethane, polyvinyl chloride and silicone adhesive.

11. The method for preparing an insulating film according to any one of claims 1 to 10, characterized in that: The steps include: Disposing the adhesive layer on at least one surface of the substrate; The polymer layer is disposed on a surface of the adhesive layer remote from the substrate.

12. The preparation method according to claim 11, characterized in that: The preparation method meets one or more of the following conditions: (1) The tensile strength of the substrate is 140 MPa to 190 MPa; (2) The tensile strength of the polymer layer is 60 MPa to 110 MPa.

13. A battery, characterized in that: The present invention comprises at least one of the insulating film according to any one of claims 1 to 10 and the insulating film prepared by the preparation method according to any one of claims 11 to 12.

14. An electrical device, characterized in that: The invention comprises at least one of the insulating film according to any one of claims 1 to 10, the insulating film obtained by the preparation method according to any one of claims 11 to 12, and the battery according to claim 13.

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