Insulating film, battery and electric equipment

Abstract

The utility model relates to the technical field of batteries, and discloses an insulating film, a battery and electric equipment, and the insulating film comprises two straight surface coating films and two corner area coating films, the two flat and straight surface coating sheets are used for coating two flat and straight surfaces of the battery cell; the two corner region coating membranes are respectively arranged on two opposite sides of one straight surface coating membrane and are used for coating two corner regions of the battery cell; the heat preservation performance of the corner area covering film pieces is better than that of the flat and straight surface covering film pieces. The lithium precipitation phenomenon can be avoided or reduced by coating the battery cell, and the slow temperature loss of the corner region of the battery cell can be ensured by further designing different thermal insulation properties of the flat surface coated film and the corner region coated film, so that the lithium precipitation condition of the corner region can be further improved, and the battery cell has the advantages of high reliability and high reliability. The safety performance and the service life of the battery cell are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an insulating film, a battery and electrical equipment. Background Art

[0002] With the advancement of technology, lithium-ion batteries are widely used in consumer electronics, energy storage and electric vehicles due to their significant advantages such as high energy density, long cycle life and green and pollution-free. In the performance evaluation of lithium-ion batteries, an essential technical indicator is the cycle life, including the cycle life under various temperatures and even in some extreme application environments.

[0003] In cycle testing, in addition to focusing on the battery's capacity retention rate, whether and when lithium plating occurs during the cycle is also a very important life evaluation indicator. As we all know, once lithium plating occurs in a battery, it will not only accelerate the degradation of performance, but also, as the amount of lithium plating accumulates, it is easy to form dendrites, which can easily cause a short circuit in the battery and cause safety hazards.

[0004] At present, when lithium-ion batteries are charging, Li+ (lithium ions) are deintercalated from the positive electrode and embedded in the negative electrode. However, when some abnormal situations occur, such as when Li+ is deintercalated from the positive electrode too quickly, but the resistance of Li+ embedding into the negative electrode is too great and the Li+ cannot be embedded in the negative electrode in equal amounts, the Li+ that cannot be embedded in the negative electrode can only gain electrons on the surface of the negative electrode, thereby forming a silvery-white metallic lithium element, and lithium precipitation occurs.

[0005] Therefore, it is necessary to improve the existing technology.

[0006] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0007] The utility model provides an insulating film, a battery and an electrical device to solve the problem of lithium deposition in lithium-ion batteries.

[0008] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0009] In a first aspect, the utility model provides an insulating film for coating a battery cell, comprising two flat surface coating films and two corner area coating films;

[0010] Two flat surface covering films are used to cover two flat surfaces of the battery cell;

[0011] Two corner region covering films are respectively arranged on two opposite sides of a flat surface covering film, and are used to cover two corner regions of the battery cell;

[0012] The thermal insulation performance of the membrane covering the corner area is better than that of the membrane covering the straight surface.

[0013] Furthermore, in the insulating film, the corner region covering film and the straight surface covering film are integrally formed and connected.

[0014] Furthermore, in the insulating film, the coating film in the corner area extends outward to form a connecting portion that can be connected to the straight surface coating film.

[0015] Furthermore, in the insulating film, a connection hole is provided on the connection portion;

[0016] The flat surface covering membrane is provided with a connecting column which can be connected with the connecting hole.

[0017] Or, a connecting column is provided on the connecting portion;

[0018] The flat surface covering membrane is provided with a connecting hole which can be connected with the connecting column.

[0019] Furthermore, in the insulating film, the corner region coating film is connected to the straight surface coating film through an adhesive layer.

[0020] Furthermore, in the insulating film, the heat transfer coefficient of the film covering the corner area is smaller than the heat transfer coefficient of the film covering the straight surface.

[0021] Furthermore, in the insulating film, the heat transfer coefficient of the film covering the corner region is equal to the heat transfer coefficient of the film covering the straight surface, but the thickness of the film covering the corner region is greater than the thickness of the film covering the straight surface.

[0022] Furthermore, in the insulating film, a heat insulating member is provided inside the film sheet covering the corner area;

[0023] The heat transfer coefficient of the heat insulating member is smaller than the heat transfer coefficient of the flat surface covered film, or the heat transfer coefficients of the heat insulating member and the film covered at the corner area are both smaller than the heat transfer coefficient of the flat surface covered film.

[0024] In a second aspect, the utility model provides a battery, comprising a battery cell and the insulating film as described in the first aspect above;

[0025] The insulating film is coated on the outer surface of the battery core.

[0026] In a third aspect, the utility model provides an electrical device, comprising the battery as described in the second aspect above.

[0027] Compared with the prior art, the utility model has the following beneficial effects:

[0028] The utility model provides an insulating film, a battery and an electrical device, comprising two flat surface coating films and two corner area coating films. On the one hand, by coating the battery cell, the battery cell can be prevented from expanding freely during the charge and discharge process, thereby preventing the increase in resistance during lithium ion migration and difficulty in lithium insertion caused by the separation of the positive and negative electrodes of the battery cell, thereby avoiding or reducing the occurrence of lithium plating. On the other hand, by designing different thermal insulation properties for the flat surface coating films and the corner area coating films, it can be ensured that the temperature of the corner area of ​​the battery cell dissipates slowly, which can further improve the lithium plating situation in the corner area of ​​the battery cell and improve the safety performance and service life of the battery cell.

[0029] The present invention has other characteristics and advantages, which will be apparent from the accompanying drawings and subsequent specific embodiments incorporated herein, or will be described in detail in the accompanying drawings and subsequent specific embodiments incorporated herein, which together are used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic diagram of the structure (flattened) of an insulating film provided in the first embodiment of the utility model;

[0032] Figure 2 It is a schematic diagram of the structure (flattened) of an insulating film provided in the first embodiment of the utility model;

[0033] Figure 3 It is a schematic diagram of the structure (folding) of an insulating film provided in the first embodiment of the utility model;

[0034] Figure 4 It is a schematic diagram of the structure (flattened) of an insulating film provided in Example 1 of the utility model.

[0035] Reference numerals:

[0036] The bottom surface is covered with a membrane 1 , the flat surface is covered with a membrane 2 , the corner area is covered with a membrane 3 , a connecting portion 4 , a connecting hole 5 , and a connecting column 6 . DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. In addition, ordinary technicians in this field can know that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0038] In the description of the present application, it should be understood that, unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as those commonly understood by those skilled in the art of the present application. In addition, any terminology used is only for the purpose of describing specific embodiments and is not intended to limit the present application.

[0039] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0040] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0041] Embodiment 1

[0042] In view of the defects of the above-mentioned prior art, the applicant, based on many years of rich practical experience and professional knowledge in the design and manufacture of such products, and in conjunction with the application of theory, actively conducts research and innovation in the hope of creating a technology that can solve the defects of the prior art. After continuous research and design, and after repeated trial samples and improvements, the present utility model with real practical value was finally created.

[0043] Please refer to Figure 1-3 , the embodiment of the utility model provides an insulating film for coating a battery cell, comprising two flat surface coating films 2 and two corner area coating films 3;

[0044] The two flat surface covering films 2 are used to cover the two flat surfaces of the battery core respectively;

[0045] Two corner region covering films 3 are respectively arranged on two opposite sides of a flat surface covering film 2, and are used to cover two corner regions of the battery cell;

[0046] The thermal insulation performance of the film sheet 3 covering the corner area is better than that of the film sheet 2 covering the straight surface.

[0047] It is understandable that the battery cell is wound into a cylindrical structure, and after being flattened by hot pressing, two straight surfaces and a corner area connected between the two straight surfaces are formed, and the corner area is a curved surface. The straight surface of the battery cell should actually correspond to the two large surfaces located at the front and back, and the corner area of ​​the battery cell should actually correspond to the two side surfaces located at the left and right.

[0048] Optionally, the insulating film further includes a bottom covering film sheet 1 for covering the bottom surface of the battery cell, and two straight covering films 2 are connected to opposite sides of the bottom covering film sheet 1. The bottom covering film sheet 1, the straight covering film sheet 2 and the corner covering film sheet 3 can achieve full insulation of the battery cell to prevent the battery cell from contacting and short-circuiting with the shell.

[0049] It should be noted that the insulating film is an important battery component, and its design has a crucial impact on battery performance and safety. The insulating film in this embodiment includes two flat surface coating films 2 and two corner area coating films 3. The insulating film in this embodiment is innovative in structure and material design, and can improve the performance and service life of the battery in the following two aspects.

[0050] First, by coating the battery cell, the insulating film can prevent the battery cell from contacting the metal shell and causing a short circuit, while also effectively preventing the battery cell from expanding freely during the charge and discharge process. This feature can prevent the positive and negative electrodes of the battery cell from separating, thereby reducing the resistance during lithium ion migration, reducing the difficulty of lithium insertion, and thus avoiding or reducing the occurrence of lithium plating. Lithium plating is an adverse reaction of the battery during use, which may cause the battery performance to decline and even cause safety hazards. By coating the battery cell, the insulating film can provide a stable environment for the battery cell, helping to maintain the performance and safety of the battery.

[0051] Secondly, during the process of charging and discharging the battery cell, the corner area of ​​the battery cell is particularly prone to lithium precipitation. The stress in the corner area is concentrated, the structure is relatively tight, and the chemical reaction rate is low, resulting in lithium precipitation. The insulating film realizes an innovative function by designing different thermal insulation properties for the flat surface coating film 2 and the corner area coating film 3, that is, the thermal insulation performance of the corner area coating film 3 is better than that of the flat surface coating film 2, so that under the separate coating of the flat surface coating film 2 and the corner area coating film 3, the temperature loss of the corner area of ​​the battery cell will be slower than the temperature loss of the flat surface, which can increase the temperature of the corner area of ​​the battery cell, increase the chemical reaction rate, and thus improve the lithium precipitation phenomenon in the corner area of ​​the battery cell. That is, this design can further improve the lithium precipitation in the corner area of ​​the battery cell, thereby further improving the performance and service life of the battery. It should be noted that temperature is a key factor affecting the degree of chemical reaction. The higher the temperature, the more intense the chemical reaction; the lower the temperature, the slower the chemical reaction.

[0052] In summary, the unique design of the insulating film effectively improves the performance and service life of the battery by preventing the free expansion of the battery cell and adjusting the corner area of ​​the battery cell to have a lower temperature dissipation rate. This insulating film can inject new vitality into the development of the battery industry, has broad application prospects in the battery industry, and is expected to bring tangible benefits to battery manufacturers and consumers.

[0053] In order to achieve that the temperature dissipation of the corner area of ​​the battery cell is slower than the temperature dissipation of the flat surface when the flat surface covering film 2 and the corner area covering film 3 are respectively covered, the present embodiment can perform the following different designs on the flat surface covering film 2 and the corner area covering film 3.

[0054] In the first design, the heat transfer coefficient of the corner region covering film 3 is smaller than the heat transfer coefficient of the straight surface covering film 2.

[0055] It should be noted that the heat transfer coefficient refers to the rate of heat transfer per unit area per unit time. In lithium-ion batteries, the heat transfer coefficient affects the temperature distribution inside the battery, and thus affects the performance of the battery.

[0056] The heat transfer coefficient of the material selected for the corner area coating film 3 is smaller than the heat transfer coefficient of the material selected for the flat surface coating film 2. When the battery cell is fixed, due to the inconsistent heat transfer coefficient, the heat transfer capacity of the corner area coating film 3 is weaker, so that the heat inside the battery is transferred more slowly and less in the corner area. This means that during the operation of the battery, the temperature of the corner area covered by the corner area coating film 3 dissipates slowly, and the temperature is increased. This increases the transmission dynamics of lithium ions, thereby improving the lithium precipitation process. The transmission of lithium ions inside the battery is a key link in the normal operation of the battery. When the battery temperature is high, the transmission speed of lithium ions is accelerated, making the battery charging and discharging process smoother. In addition, high temperature can also reduce the internal resistance of lithium-ion batteries and improve the cycle life and safety of batteries.

[0057] In the second design, the heat transfer coefficient of the corner region covering film 3 is equal to the heat transfer coefficient of the straight surface covering film 2, but the thickness of the corner region covering film 3 is greater than the thickness of the straight surface covering film 2.

[0058] It should be noted that in the first design, the heat transfer coefficient of the coating film 3 in the corner area is reduced to be smaller than the heat transfer coefficient of the coating film 2 on the flat surface, thereby reducing the heat transfer capacity of the coating film 3 in the corner area and slowing down the temperature loss in the corner area. The concept of this design is that the smaller the heat transfer coefficient, the worse the heat transfer effect, the higher the temperature, and thus the bulging problem can be better solved. However, in actual application, it is found that the second design also has its unique advantages.

[0059] The core idea of ​​the second design is that even if the heat transfer coefficient of the corner region coating film 3 does not need to be less than the heat transfer coefficient of the flat surface coating film 2, that is, the corner region coating film 3 and the screen straight surface coating film 2 are made of the same material, the heat transfer capacity of the corner region coating film 3 can be reduced. This design method is more flexible and more adaptable. For example, when the heat transfer coefficients of the two are equal, the goal can be achieved by adjusting the thickness of the two.

[0060] Specifically, in the second design, the thickness of the corner region coating film 3 is set to be greater than the thickness of the flat surface coating film 2. The reason for this is that the heat transfer capacity is inversely proportional to the thickness of the film. The greater the thickness, the weaker the heat transfer capacity and the stronger the thermal insulation performance. Therefore, while keeping the bulging restricted, by increasing the thickness of the corner region coating film 3, its heat transfer capacity can be further reduced, so that the thermal insulation performance of the corner region coating film 3 is better, and the lithium precipitation of the corner region coated by the corner region coating film 3 is improved.

[0061] In summary, the second design cleverly utilizes the relationship between heat transfer coefficient and thickness, achieving the goal of reducing the heat transfer capacity of the coating film 3 in the corner area while limiting bulging. Compared with the first design, the second design has a wider applicability. Not only does the heat transfer coefficient not need to be less than that of the flat coating film 2, but the goal can be achieved by adjusting the thickness. This provides more possibilities in practical applications and helps to further optimize product performance.

[0062] In the third design, a heat insulating member is provided inside the corner region covering the membrane 3;

[0063] The heat transfer coefficient of the heat insulating member is smaller than the heat transfer coefficient of the flat surface covering film sheet 2 , or the heat transfer coefficients of the heat insulating member and the corner area covering film sheet 3 are both smaller than the heat transfer coefficient of the flat surface covering film sheet 2 .

[0064] It should be noted that the third design is also intended to reduce the heat transfer capacity of the coating film 3 in the corner area, making it worse than the heat transfer capacity of the flat surface coating film 2. However, the third design method is different from the first two design strategies. In the third design, the following innovative measures are taken: a heat insulating member with a heat transfer coefficient smaller than that of the flat surface coating film 2 is set inside the coating film 3 in the corner area, such as aerogel felt, vacuum plate, etc., while there is no such configuration inside the flat surface coating film 2. This can not only effectively control the bulging problem and improve the lithium precipitation in the corner area of ​​the battery cell, but also strengthen the fixation of the battery cell due to the hardness of the heat insulating member, thereby improving the performance of the entire battery assembly.

[0065] It is understandable that in actual operation, we can flexibly choose the first, second or third design scheme according to specific needs and conditions. If reducing the heat transfer coefficient of the material can better solve the lithium plating problem in the corner area, we can choose the first design; conversely, if thickness adjustment can bring better thermal insulation effect, then the second design will be a better choice, and so on. By mastering these three design methods, we can better cope with various challenges and achieve continuous improvement of product performance.

[0066] Please refer again Figure 1 In the first implementation of the present embodiment, the corner region covering film 3 and the straight surface covering film 2 can be integrally formed and connected.

[0067] When it is an integrally formed connection, since the insulating film produced is in an unfolded state, that is, only one side of the corner area covering film sheet 3 is integrally connected with the straight surface covering film sheet 2, and the other side is a free end, in order to ensure that the insulating film has strong covering properties after folding, the corner area covering film sheet 3 extends outward to form a connecting portion 4 that can be matched and connected with the straight surface covering film sheet 2.

[0068] It should be noted that after the insulating film is folded, the corner region covering film sheet 3 needs to be connected with the flat surface covering film sheet 2 through the connecting portion 4 to maintain the folded shape. Figure 3 As shown, the battery cell can be stably coated. In order to achieve the coordinated connection between the two, as shown Figure 1 As shown, on one hand, a connecting hole 5 may be provided on the connecting portion 4 ; and a connecting column 6 which can be connected with the connecting hole 5 is provided on the flat surface covering membrane 2 .

[0069] like Figure 2 As shown, on the other hand, a connecting post 6 may be provided on the connecting portion 4 ; and a connecting hole 5 which can be connected with the connecting post 6 is provided on the flat surface covering membrane 2 .

[0070] The connection between the connecting column 6 and the connecting hole 5 forms a stable connection structure. This design not only makes the corner area covering membrane 3 and the straight surface covering membrane 2 more stable during use, but also facilitates the installation and removal of the components. In addition, the material and structure of the connecting column 6 also need to be carefully selected and designed to have sufficient strength and wear resistance to meet the needs of long-term use.

[0071] Please refer to Figure 4 In the second implementation of this embodiment, the corner area covering film 3 is connected to the flat surface covering film 2 through an adhesive layer.

[0072] It should be noted that, in this embodiment, both sides of the corner region covering film sheet 3 are free ends, so both sides need to be connected to the flat surface covering film sheet 2 through an adhesive layer to ensure that the insulating film has strong covering properties after folding.

[0073] It is understandable that the method of connecting the corner area covering film 3 and the flat covering film 2 by means of an adhesive layer is simple and effective, and can ensure the stability and reliability of the insulating film after folding. At the same time, due to the presence of the adhesive layer, the durability and service life of the insulating film can also be improved.

[0074] Although the terms such as bottom coating film, flat coating film, corner coating film are used more frequently in this application, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

[0075] The utility model provides an insulating film, a battery and an electrical device, comprising a bottom coating film, two flat coating films and two corner region coating films. On the one hand, by coating the battery cell, the battery cell can be prevented from expanding freely during the charge and discharge process, thereby preventing the increase in resistance during lithium ion migration and difficulty in lithium insertion caused by the separation of the positive and negative electrodes of the battery cell, thereby avoiding or reducing the occurrence of lithium plating. On the other hand, by designing different thermal insulation properties for the flat coating film and the corner region coating film, it can be ensured that the temperature of the corner region of the battery cell dissipates slowly, which can further improve the lithium plating situation in the corner region of the battery cell and improve the safety performance and service life of the battery cell.

[0076] Embodiment 2

[0077] The present utility model embodiment provides a battery, comprising a battery cell and an insulating film as provided in the first embodiment;

[0078] The insulating film is coated on the outer surface of the battery cell.

[0079] It should be noted that the battery should also include necessary component designs such as a shell, a top cover, and an adapter. The specific function of these component designs is to ensure the normal operation of various functions of the battery. In view of the fact that these component designs have been implemented in many existing technologies and are not the focus of this design, they will not be elaborated in depth here.

[0080] The battery provided in this embodiment has good cycle performance and structural reliability due to the insulating film provided in the above-mentioned embodiment 1.

[0081] In addition, the battery in this embodiment can be used in electronic devices such as electronic devices, electric vehicles or power storage systems, but is not limited to it. Among them, the electronic device can be, for example, various computers, mobile phones, display screens and other devices that use batteries as driving power sources. Electric vehicles can be, for example, electric cars, electric tricycles, electric bicycles, etc. that use batteries as driving power sources. The power storage system can be, for example, a power storage system that uses batteries as power storage sources.

[0082] In these electronic devices, the battery can be electrically connected to the electrical components to provide electrical energy to the electrical components. Since the battery provided in this application has excellent cycle capacity, it is conducive to the use of electronic devices in application scenarios such as outdoor energy storage, short-term backup power and mobile energy storage, thereby making the application scenarios of electronic devices more extensive.

[0083] Embodiment 3

[0084] The utility model provides an electrical device, comprising the battery as described in the second embodiment.

[0085] It should be noted that the battery refers to a battery cell. In this embodiment, the electrical device may be powered directly by the battery cell, or by a battery pack formed by connecting a plurality of battery cells in parallel, in series or in a mixed manner.

[0086] The electrical equipment provided in this embodiment has the battery provided in the above-mentioned second embodiment, so the battery cycle performance and structural reliability of the electrical equipment are good.

[0087] It is understandable that, in addition to a battery for providing electrical energy, an electrical device should also include an object that receives electrical energy, namely, the electrical subject. The battery is connected to the electrical subject, and the electrical subject can achieve set functions under the drive of electrical energy.

[0088] In summary, after reading this detailed disclosure, it will be apparent to those skilled in the art that the aforementioned detailed disclosure may be presented only by way of example and may not be restrictive. Although not explicitly stated herein, it will be appreciated by those skilled in the art that this application is intended to encompass various reasonable changes, improvements and modifications to the embodiments. These changes, improvements and modifications are intended to be proposed by this application and are within the spirit and scope of the exemplary embodiments of this application.

[0089] In addition, certain terms in this application have been used to describe embodiments of the present application. For example, "one embodiment", "embodiment" and / or "some embodiments" mean that a particular feature, structure or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. Therefore, it can be emphasized and should be understood that two or more references to "embodiment" or "one embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics may be appropriately combined in one or more embodiments of the present application.

[0090] It should be understood that in the foregoing description of the embodiments of the present application, in order to help understand a feature and for the purpose of simplifying the present application, the present application combines various features in a single embodiment, drawing or its description. However, this does not mean that the combination of these features is necessary. When reading the present application, it is entirely possible for a person skilled in the art to extract some of the features and understand them as separate embodiments. In other words, the embodiments in the present application can also be understood as the integration of multiple secondary embodiments. This is also true when the content of each secondary embodiment is less than all the features of a single aforementioned disclosed embodiment.

[0091] Finally, it should be understood that the embodiments of the application disclosed herein are explanations of the principles of the embodiments of the present application. Other modified embodiments are also within the scope of the present application. Therefore, the embodiments disclosed in the present application are merely examples and not limitations. Those skilled in the art can adopt alternative configurations according to the embodiments in the present application to implement the application in the present application. Therefore, the embodiments of the present application are not limited to the embodiments accurately described in the application.

Claims

1. An insulating film for coating a battery cell, characterized in that: It comprises two straight surface covering membranes (2) and two corner area covering membranes (3); The two flat surface covering films (2) are used to cover the two flat surfaces of the battery core; The two corner region covering films (3) are respectively arranged on two opposite sides of one of the flat surface covering films (2) and are used to cover the two corner regions of the battery cell; The thermal insulation performance of the corner region coating film (3) is better than the thermal insulation performance of the straight surface coating film (2).

2. The insulating film according to claim 1, wherein The corner region covering membrane (3) is integrally formed and connected with the straight surface covering membrane (2).

3. The insulating film according to claim 2, characterized in that The corner region covering membrane (3) extends outward to form a connecting portion (4) that can be connected to the straight surface covering membrane (2).

4. The insulating film according to claim 3, characterized in that The connecting portion (4) is provided with a connecting hole (5); The flat surface-coated membrane (2) is provided with a connecting column (6) which can be connected to the connecting hole (5); Or, a connecting column (6) is provided on the connecting portion (4); The flat surface-coated membrane sheet (2) is provided with a connecting hole (5) which can be matched and connected with the connecting column (6).

5. The insulating film according to claim 1, wherein The corner region covering film (3) is connected to the straight surface covering film (2) via an adhesive layer.

6. The insulating film according to claim 1, wherein The heat transfer coefficient of the corner region covering membrane (3) is smaller than the heat transfer coefficient of the straight surface covering membrane (2).

7. The insulating film according to claim 1, wherein The heat transfer coefficient of the corner region covering film (3) is equal to the heat transfer coefficient of the straight surface covering film (2), but the thickness of the corner region covering film (3) is greater than the thickness of the straight surface covering film (2).

8. The insulating film according to claim 1, wherein A heat insulating component is arranged inside the corner region covering membrane (3); The heat transfer coefficient of the heat insulating member is smaller than the heat transfer coefficient of the flat surface covering membrane (2), or the heat transfer coefficients of the heat insulating member and the corner area covering membrane (3) are both smaller than the heat transfer coefficient of the flat surface covering membrane (2).

9. A battery, characterized in that: A battery cell and an insulating film as claimed in any one of claims 1 to 8; The insulating film is coated on the outer surface of the battery core.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

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