Insulating film, energy storage device, and energy storage system

Abstract

The embodiment of the present application provides an insulating film, an energy storage device and an energy storage system. The insulating film is used for cell insulation, and the insulating film comprises exhaust holes, the exhaust holes penetrate through two surfaces in the thickness direction of the insulating film, the insulating film has an overlapping area, and the exhaust holes are located in the overlapping area of the insulating film. The technical scheme of the present application can improve the exhaust effect of the cell when thermal runaway occurs, thereby improving the safety performance of the energy storage device.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to an insulating film, an energy storage device, and an energy storage system. Background Technology

[0002] With the development of the new energy industry, energy storage products, especially rechargeable batteries, are attracting increasing attention. Rechargeable batteries can be used in various fields such as power tools, mobile terminals, electric bicycles, electric motorcycles, and electric vehicles. Rechargeable batteries typically have an insulating sheet between the battery cell and the metal casing. The insulating sheet covers the battery cell to separate and insulate it from the metal casing.

[0003] However, in practical applications, in pursuit of high energy density, the core inside the battery cell is relatively large, resulting in a very small gap between the core and the casing. This leads to poor venting when thermal runaway occurs, affecting the safety performance of the secondary battery. Utility Model Content

[0004] This application provides an insulating film, an energy storage device, and an energy storage system that can improve the venting effect of the battery cell when thermal runaway occurs, thereby improving the safety performance of the energy storage device.

[0005] In a first aspect, embodiments of this application provide an insulating film. The insulating film is used to insulate a battery cell. The insulating film includes vent holes that penetrate both surfaces of the insulating film in the thickness direction. The insulating film has an overlapping region, and the vent holes are located within the overlapping region of the insulating film.

[0006] In one embodiment, the battery cell includes a first side and a second side, wherein the first side and the second side are disposed opposite to each other along the length direction of the battery cell;

[0007] The overlapping area further includes a first overlapping area, a second overlapping area, a third overlapping area, and a fourth overlapping area. The first overlapping area and the second overlapping area are both used to cover the first side of the battery cell, and the first overlapping area and the second overlapping area are arranged sequentially in the height direction of the battery cell. The third overlapping area and the fourth overlapping area are both used to cover the second side of the battery cell, and the third overlapping area and the fourth overlapping area are arranged sequentially in the height direction of the battery cell.

[0008] The vent is disposed in at least one of the first overlapping area, the third overlapping area, the second overlapping area, and the fourth overlapping area.

[0009] In one embodiment, the insulating film further includes a first sheet, a second sheet, and a bottom sheet. The bottom sheet is connected to the first sheet and the second sheet, and the first sheet and the second sheet are stacked on the first side and the second side to form a first overlapping area and a third overlapping area. The bottom sheet is stacked on the first side and the second side respectively with the first sheet and the second sheet, and the bottom sheet has a portion that overlaps with the first sheet and the second sheet to form a second overlapping area and a fourth overlapping area.

[0010] The vent is provided in at least one of the first sheet, the second sheet, and the bottom sheet.

[0011] In one embodiment, the vent is disposed in at least one of the first sheet and the second sheet, and the vent is located within the first overlapping region and / or the third overlapping region.

[0012] In one embodiment, both the first sheet and the second sheet are provided with the vent holes in the first overlapping area, and the vent holes of the first sheet and the second sheet do not overlap in the first overlapping area; and / or, both the first sheet and the second sheet are provided with the vent holes in the third overlapping area, and the vent holes of the first sheet and the second sheet do not overlap in the third overlapping area.

[0013] In one embodiment, the vent is located within the second overlapping region and / or the fourth overlapping region.

[0014] In one embodiment, the vent is also provided on the bottom sheet.

[0015] Within the second overlapping region and / or the fourth overlapping region, the vent holes on at least two of the bottom sheet, the first sheet, and the second sheet do not overlap.

[0016] In one embodiment, the battery cell further includes a first surface, a second surface, and a bottom surface. The first surface and the second surface are disposed opposite to each other along the width direction of the battery cell and are connected to the first side surface and the second side surface. The bottom surface is a surface in the height direction of the battery cell and is connected to the first surface, the second surface, the first side surface, and the second side surface.

[0017] The first sheet includes a first attachment portion and two first covering portions connected to both sides of the first attachment portion. The two first covering portions are respectively used to cover at least a portion of the first side and the second side of the battery cell. The second sheet includes a second attachment portion and two second covering portions connected to both sides of the second attachment portion. The two second covering portions are respectively used to cover at least a portion of the first side and the second side of the battery cell. The bottom sheet includes a third attachment portion and two third covering portions connected to both sides of the third attachment portion. The two third covering portions are respectively used to cover at least a portion of the first side and the second side of the battery cell.

[0018] The third attachment portion is connected to the first attachment portion and the second attachment portion. The first attachment portion is used to cover the first surface of the battery cell, the second attachment portion is used to cover the second surface of the battery cell, and the third attachment portion is used to cover the bottom surface of the battery cell.

[0019] The two first covering portions are respectively stacked with the second covering portion on the same side, forming the first overlapping area and the third overlapping area respectively. The two third covering portions are simultaneously stacked with the first covering portion and the second covering portion on the same side, forming the second overlapping area and the fourth overlapping area respectively.

[0020] In one embodiment, in the height direction of the battery cell, the first covering portion and the second covering portion on the same side form a notch with the third attachment portion, and the third covering portion covers the notch.

[0021] In one embodiment, along the length of the battery cell, the third covering portion is located on the side opposite to the first covering portion and the second covering portion on the same side of the battery cell.

[0022] In one embodiment, along the length of the battery cell, the first covering portion, the second covering portion, and the third covering portion on the same side are at least partially connected and fixed by heat fusion or adhesive bonding.

[0023] In one embodiment, the number of exhaust holes is multiple, and the multiple exhaust holes are arranged in a straight line, a serpentine pattern, or a matrix.

[0024] Secondly, embodiments of this application provide an energy storage device. The energy storage device includes a housing, a battery cell, an end cap assembly, and an insulating film. The battery cell and the insulating film are both housed within the housing. The insulating film is located between the battery cell and the housing and covers the battery cell. The end cap assembly is mounted on the battery cell and sealed to the housing.

[0025] Thirdly, embodiments of this application provide an energy storage system. The energy storage system includes the energy storage device.

[0026] In related technologies, secondary batteries typically have an insulating sheet between the battery cell and the metal casing. The insulating sheet covers the battery cell to separate and insulate it from the metal casing. However, in practical applications, to achieve high energy density, the core inside the battery cell is relatively large, resulting in a very small gap between the core and the casing. Moreover, existing insulating sheets mostly surround the sides and bottom of the battery cell. When the battery cell experiences thermal runaway and generates a large amount of gas, the gas can only escape from the top of the battery cell, which is not covered by the insulating sheet. This leads to poor venting from the sides of the battery cell, which cannot meet the requirement for rapid gas discharge. If gas accumulates inside the secondary battery, it can easily affect the safety performance of the secondary battery.

[0027] In this embodiment, the insulating film covers the sides and bottom of the battery cell, and the insulating film has an overlapping area on the side of the battery cell, within which an exhaust port is provided. During the operation of the energy storage device, if the battery cell experiences thermal runaway, a large amount of gas will be generated. The gas in the battery cell can not only be discharged through the top perforation of the insulating film, but also cause the insulating film to expand in the direction away from the battery cell and be discharged through the laminations of the insulating film and the exhaust port.

[0028] It is understood that the gas generated by the battery cell is discharged through the overlapping gaps in the side of the insulating film and the vent holes located in the overlapping area. The gas discharged through the side of the insulating film and the gas discharged through the top perforation of the insulating film converge at the top of the casing and is depressurized through the end cap assembly connected to the opening of the casing. The vent holes on the side of the insulating film accelerate the gas discharge rate of the battery cell under thermal runaway, and prevent the gas generated by the battery cell from accumulating inside the energy storage device and causing safety hazards to the energy storage device.

[0029] In addition, there can be multiple vents. Multiple vents located in the same overlapping area can not overlap at all in the thickness direction of the overlapping area of ​​the insulating film, so as to ensure that the insulating film does not leak the internal battery cell and can completely separate and insulate the battery cell and the outer shell, ensuring the insulation performance of the insulating film and further improving the safety performance of the energy storage device. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application;

[0031] Figure 2 for Figure 1 The diagram shows the structural schematic of the energy storage device in the energy storage system.

[0032] Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device.

[0033] Figure 4 for Figure 3 The diagram shows the structure of the insulating film of the energy storage device in a folded state;

[0034] Figure 5 for Figure 4 The diagram shown is a structural schematic of the insulating film in its flattened state.

[0035] Figure 6 for Figure 4 The image shows a left perspective view of the first embodiment of the insulating film in a folded state;

[0036] Figure 7 for Figure 4 The image shows a right-side perspective view of the first embodiment of the insulating film in a folded state;

[0037] Figure 8 for Figure 4 The left perspective view of the second embodiment of the insulating film in a folded state is shown.

[0038] Figure 9 for Figure 4 The image shows a right-side perspective view of the second embodiment of the insulating film in a folded state;

[0039] Figure 10 for Figure 4 The left perspective view of the third embodiment of the insulating film in a folded state is shown.

[0040] Figure 11 for Figure 4 The right-side perspective view of the third embodiment of the insulating film in a folded state.

[0041] The names corresponding to the markings in the attached figures are as follows: Energy storage system 4000, high-voltage cable 4100, first power conversion device 4200, second power conversion device 4300, energy storage device 1000, outer casing 200, opening 201, receiving cavity 202, end cap assembly 300, battery cell 400, first side 401, second side 402, first surface 403, second surface 404, bottom surface 405, top surface 406, side 407, insulating film 100, vent Q, first sheet 10, first covering part a, first sub-covering part 11, first vent Q1, second sub-covering part 12, second vent Q2, first attachment part 13, second sheet 20, second covering part b, third sub-covering part b, second ... Covering part 21, third vent Q3, fourth sub-covering part 22, fourth vent Q4, second attachment part 23, bottom sheet 30, third covering part c, fifth sub-covering part 31, fifth vent Q5, sixth sub-covering part 32, sixth vent Q6, third attachment part 33, first crease 101, second crease 102, third crease 103, fourth crease 104, fifth crease 105, sixth crease 106, seventh crease 107, eighth crease 108, opening 110, receiving groove 120, notch 130, first notch 130a, second notch 130b, overlapping area M, first overlapping area M1, second overlapping area M2, third overlapping area M3, fourth overlapping area M4. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly specified. Furthermore, the terms "same," "equal," or "parallel" used below are all allowed to have certain tolerances.

[0044] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0045] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form for future applications. Currently, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels.

[0046] Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak hours, and excessive power during off-peak hours. Unstable voltage can also damage the power grid. Therefore, due to insufficient electricity demand or insufficient grid capacity, solving these problems requires energy storage. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, this energy can be converted back into electrical energy and released. Simply put, energy storage is like a large "power bank," storing electrical energy when solar and wind power are abundant and releasing the stored electricity when needed.

[0047] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a set of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage media. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electricity is released for use, or transferred to places with a shortage of electricity for use.

[0048] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices include:

[0049] (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can assist renewable energy power generation in meeting grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, energy storage power stations can achieve load matching of power in time and space, enhance the absorption capacity of renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy power generation, and are of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation.

[0050] (2) Energy storage containers applied on the grid side mainly function as peak shaving, frequency regulation and grid congestion relief. In terms of peak shaving, they can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption.

[0051] (3) Small-scale energy storage cabinets applied to the electricity consumption side primarily function to facilitate self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improve power supply reliability. Depending on the application scenario, electricity consumption-side energy storage can be categorized into commercial and industrial energy storage cabinets, residential energy storage devices, and energy storage charging piles, which are generally used in conjunction with distributed photovoltaic systems. Considering that photovoltaic power generation occurs during the day while user loads are typically higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is required in communication base stations, data centers, and other fields for backup power.

[0052] In some embodiments, please refer to Figure 1 , Figure 1 This is a schematic diagram of an energy storage system according to an embodiment of this application. Figure 1 The embodiments are illustrated using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device 1000 of this application is not limited to its generation / distribution side energy storage scenario.

[0053] This application provides an energy storage system 4000. The energy storage system 4000 is used to supply power to electrical equipment. The energy storage system 4000 includes: a high-voltage cable 4100, a first power conversion device 4200, a second power conversion device 4300, and the energy storage device 1000 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4300 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 1000 through grid connection. The energy storage device 1000 is connected to the high-voltage cable 4100 and outputs smooth electricity to supply the power consumption side of the distribution network, achieving peak shaving and frequency regulation, and stable grid operation; or, the wind power conversion device initially... Finally, it connects to the high-voltage cable 4100. Under normal power generation conditions, the electricity output from the wind power conversion device is supplied to the power consumption side of the distribution network via the high-voltage cable. When the current power load is low and the wind power conversion device generates excess electricity, the excess electricity is first stored in the energy storage device 1000, reducing wind and solar curtailment rates and improving the problem of new energy power generation consumption. Furthermore, when the power load is high, the grid issues an instruction to transmit the electricity stored in the energy storage device 1000 in conjunction with the high-voltage cable 4100 in grid-connected mode to supply electricity to the power consumption side, providing various services such as peak shaving, frequency regulation, and backup for grid operation, fully leveraging the grid's peak shaving function, promoting peak shaving and valley filling, and alleviating grid power supply pressure. It can be understood that the energy storage device 1000 in the energy storage system 4000 is used to supply power to electrical equipment.

[0054] In some embodiments on the distribution network side, the first power conversion device 4200 can be a photovoltaic power conversion device. The energy storage device 1000 is connected to the high-voltage cable 4100 and installed downstream of the high-voltage cable 4100 between the user load and the user load. The power output by the photovoltaic power conversion device is stored in the energy storage device 1000, which can respond in a timely manner to act as a backup power source when the power grid / distribution network fails. Alternatively, it can provide power supply support to alleviate line congestion when the high-voltage cable 4100 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0055] Optionally, the first power conversion device 4200 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4300 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 4200 and the second power conversion device 4300 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0056] Optionally, the energy storage device 1000 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, aerospace, charging piles, and electric vehicles.

[0057] Optionally, the energy storage device 1000 may include, but is not limited to, single-cell batteries, or battery modules, battery packs, battery clusters, power banks, energy storage cabinets / containers, and other battery integrated systems composed of single-cell batteries. The actual application form of the energy storage device 1000 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 1000. This application embodiment only uses a multi-cell battery as an example for illustration.

[0058] Optionally, when the energy storage device 1000 is a single battery cell, the energy storage device 1000 can be, but is not limited to, at least one of cylindrical, square, prismatic, or other shaped batteries.

[0059] Optionally, the battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application does not specifically limit it.

[0060] Please see Figure 2 and Figure 3 , Figure 2 for Figure 1 The diagram shown is a structural schematic of the energy storage device in the energy storage system. Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device.

[0061] For ease of description, the length direction of the energy storage device 1000 is defined as the Y-axis direction, the height direction as the Z-axis direction, and the width direction as the X-axis direction. The X-axis, Y-axis, and Z-axis directions are all mutually perpendicular. It should be noted that in this embodiment, the length dimension of the energy storage device 1000 is greater than or equal to its width dimension.

[0062] The directional terms such as "upper," "lower," "bottom," "top," "right," and "left" mentioned in the embodiments of this application are based on the appendix to the specification. Figure 2 The description is based on the orientation shown. It does not constitute a limitation on the actual application scenario of the energy storage device 1000. Specifically, the positive direction towards the Z-axis is defined as the top or upper part of the energy storage device 1000, and the negative direction towards the Z-axis is defined as the lower part or lower part of the energy storage device 1000. The positive direction towards the Y-axis is defined as the left side of the energy storage device 1000, and the negative direction towards the Y-axis is defined as the right side of the energy storage device 1000.

[0063] The energy storage device 1000 includes a housing 200, an end cap assembly 300, a battery cell 400, and an insulating film 100. The housing 200 has an opening 201 and a receiving cavity 202. The opening 201 and the receiving cavity 202 are connected. The battery cell 400 and the insulating film 100 are both housed within the receiving cavity 202. The insulating film 100 is disposed between the battery cell 400 and the housing 200. The insulating film 100 covers the outer side of the battery cell 400 and exposes its top. The insulating film 100 serves to separate and insulate the battery cell 400 from the housing 200, protecting the battery cell 400 and preventing short circuits between them. The end cap assembly 300 is mounted on one end of the battery cell 400 and seals the opening 201 of the housing 200 to isolate the internal and external environments of the energy storage device 1000. In this embodiment, the housing 200 is a metal casing.

[0064] The battery cell 400 includes a side surface 407, a bottom surface 405, and a top surface 406. The side surface 407 includes a first side surface 401, a second side surface 402, a first surface 403, and a second surface 404. The first side surface 401 and the second side surface 402 are arranged opposite to each other along the length direction (Y-axis direction) of the battery cell 400. The first surface 403 and the second surface 404 are arranged opposite to each other along the width direction (X-axis direction) of the battery cell 400. Both the first surface 403 and the second surface 404 are connected to the first side surface 401 and the second side surface 402, and together with the first side surface 401 and the second side surface 402, they form the side surface of the battery cell 400. The bottom surface 405 and the top surface 406 are arranged opposite to each other along the height direction (Z-axis direction) of the battery cell 400. Both the bottom surface 405 and the top surface 406 are connected to the first side surface 401 and the second side surface 402, and both the bottom surface 405 and the top surface 406 are connected to the first surface 403 and the second surface 404.

[0065] In this embodiment, the length dimension of the battery cell 400 is greater than or equal to the width dimension of the battery cell 400. The area of ​​the first side 401 of the battery cell 400 is less than or equal to the area of ​​the first surface 403 and the second surface 404, and the area of ​​the second side 402 is less than or equal to the area of ​​the first surface 403 and the second surface 404.

[0066] Please see Figure 4 and Figure 5 , Figure 4 for Figure 3 The diagram shown is a structural schematic of the insulating film of the energy storage device in a folded state. Figure 5 for Figure 4 The diagram shows the structure of the insulating film in its flattened state. Figure 5 The dashed lines in the middle represent the seventh and eighth creases.

[0067] The insulating film 100 includes both a flattened state and a folded state. Before being wrapped around the battery cell 400, the insulating film 100 is in a flattened state, such as... Figure 5 As shown, the insulating film 100 at this time has a sheet-like structure. After the insulating film 100 covers the battery cell 400, the insulating film 100 is in a folded state, as shown... Figure 4 As shown, the insulating film 100 forms a cylindrical structure. In this embodiment, the insulating film 100 is a Mylar film.

[0068] In this embodiment, the insulating film 100 includes a first sheet 10, a second sheet 20, and a bottom sheet 30. The bottom sheet 30 is located between and connected to the first sheet 10 and the second sheet 20. A first crease 101 is formed between the first sheet 10 and the bottom sheet 30, and the first sheet 10 and the bottom sheet 30 can be bent relative to each other about the first crease 101. A second crease 102 is formed between the second sheet 20 and the bottom sheet 30, and the second sheet 20 and the bottom sheet 30 can be bent relative to each other about the second crease 102. In this embodiment, the first sheet 10, the second sheet 20, and the bottom sheet 30 are all sheet structures.

[0069] In this embodiment, the insulating film 100 further includes a vent Q. The vent Q is disposed within the overlapping area M of the insulating film 100 in the folded state. The vent Q is disposed in at least one of the first sheet 10, the second sheet 20, and the bottom sheet 30. The number of vents Q can be one or more.

[0070] Specifically, the first sheet 10 includes a first covering portion a and a first attaching portion 13. The first covering portion a includes a first sub-covering portion 11 and a second sub-covering portion 12. The first attaching portion 13 is located between and connected to the first sub-covering portion 11 and the second sub-covering portion 12. A third crease 103 is formed between the first attaching portion 13 and the first sub-covering portion 11, and the first attaching portion 13 and the first sub-covering portion 11 can be bent relative to each other about the third crease 103. A fourth crease 104 is formed between the first attaching portion 13 and the second sub-covering portion 12, and the first attaching portion 13 and the second sub-covering portion 12 can be bent relative to each other about the fourth crease 104. In this embodiment, the first attaching portion 13 is a rectangular sheet. The first sub-covering portion 11 and the second sub-covering portion 12 are both right-angled trapezoidal sheets.

[0071] In one embodiment, the first sub-covering portion 11 includes a plurality of vent holes Q. For ease of description, the vent holes Q on the first sub-covering portion 11 are named first vent holes Q1. The plurality of first vent holes Q1 extend through both surfaces of the first sub-covering portion 11 in the thickness direction. The first vent holes Q1 are used to discharge gas generated by the power core 400 in the event of thermal runaway. The plurality of first vent holes Q1 can be arranged in a straight line, a matrix, or a serpentine pattern along the length direction (i.e., the Z-axis direction) of the first sub-covering portion 11. Adjacent first vent holes Q1 are spaced apart or tangentially arranged. The first vent holes Q1 can be, but are not limited to, through holes of regular or irregular shapes such as circular holes, triangular holes, rectangular holes, and oblong holes. The shapes of the plurality of first vent holes Q1 can be the same or different. For example, the plurality of first vent holes Q1 have the same shape and are all circular holes. The plurality of first vent holes Q1 are arranged in a straight line along the length direction of the first sub-covering portion 11 and are spaced apart from each other.

[0072] In one embodiment, the number of first exhaust ports Q1 may also be one.

[0073] In one embodiment, the second sub-covering portion 12 includes a plurality of vent holes Q. For ease of description, the vent holes Q on the second sub-covering portion 12 are named second vent holes Q2. The plurality of second vent holes Q2 extend through both surfaces of the second sub-covering portion 12 in the thickness direction. The second vent holes Q2 are used to discharge gases generated by the power core 400 in the event of thermal runaway. The plurality of second vent holes Q2 can be arranged in a straight line, a matrix, or a serpentine pattern along the length direction (i.e., the Z-axis direction) of the second sub-covering portion 12. Adjacent second vent holes Q2 are spaced apart or tangentially arranged. The second vent holes Q2 can be, but are not limited to, through holes of regular or irregular shapes such as circular holes, triangular holes, rectangular holes, and oblong holes, and the shapes of the plurality of second vent holes Q2 can be the same or different. For example, the plurality of second vent holes Q2 have the same shape and are all circular holes. The plurality of second vent holes Q2 are arranged in a straight line along the length direction of the second sub-covering portion 12 and are spaced apart from each other.

[0074] In one embodiment, the number of second exhaust ports Q2 may also be one.

[0075] The second sheet 20 includes a second covering portion b and a second attaching portion 23. The second covering portion b includes a third sub-covering portion 21 and a fourth sub-covering portion 22. The second attaching portion 23 is located between and connected to the third sub-covering portion 21 and the fourth sub-covering portion 22. A fifth crease 105 is formed between the second attaching portion 23 and the third sub-covering portion 21, and the second attaching portion 23 and the third sub-covering portion 21 can be bent relative to each other about the fifth crease 105. A sixth crease 106 is formed between the second attaching portion 23 and the fourth sub-covering portion 22, and the second attaching portion 23 and the fourth sub-covering portion 22 can be bent relative to each other about the sixth crease 106. In this embodiment, the second attaching portion 23 is a rectangular sheet. The third sub-covering portion 21 and the fourth sub-covering portion 22 are both right-angled trapezoidal sheets.

[0076] In one embodiment, the third sub-covering portion 21 includes a plurality of vent holes Q. For ease of description, the vent holes Q on the third sub-covering portion 21 are named third vent holes Q3. The plurality of third vent holes Q3 extend through both surfaces of the third sub-covering portion 21 in the thickness direction. The third vent holes Q3 are used to discharge gases generated by the power core 400 during thermal runaway. The plurality of third vent holes Q3 can be arranged in a straight line, a matrix, or a serpentine pattern along the length direction (i.e., the Z-axis direction) of the third sub-covering portion 21. Adjacent third vent holes Q3 are spaced apart or tangentially arranged. The third vent holes Q3 can be, but are not limited to, through holes of regular or irregular shapes such as circular holes, triangular holes, rectangular holes, and oblong holes, and the shapes of the plurality of third vent holes Q3 can be the same or different. For example, the plurality of third vent holes Q3 have the same shape and are all circular holes. The plurality of third vent holes Q3 are arranged in a straight line along the length direction of the third sub-covering portion 21 and are spaced apart from each other.

[0077] In one embodiment, the number of third exhaust ports Q3 may also be one.

[0078] In one embodiment, the fourth sub-covering portion 22 includes a plurality of vent holes Q. For ease of description, the vent holes Q on the third sub-covering portion 21 are named fourth vent holes Q4. The plurality of fourth vent holes Q4 extend through both surfaces of the fourth sub-covering portion 22 in the thickness direction. The fourth vent holes Q4 are used to discharge gases generated by the power core 400 in the event of thermal runaway. The plurality of fourth vent holes Q4 can be arranged in a straight line, a matrix, or a serpentine pattern along the length direction (i.e., the Z-axis direction) of the fourth sub-covering portion 22. Adjacent fourth vent holes Q4 are spaced apart or tangentially arranged. The fourth vent holes Q4 can be, but are not limited to, through holes of regular or irregular shapes such as circular holes, triangular holes, rectangular holes, and oblong holes, and the shapes of the plurality of fourth vent holes Q4 can be the same or different. For example, the plurality of fourth vent holes Q4 have the same shape and are all circular holes. The plurality of fourth vent holes Q4 are arranged in a straight line along the length direction of the fourth sub-covering portion 22 and are spaced apart from each other.

[0079] In one embodiment, the number of fourth vent holes Q4 may also be one.

[0080] The bottom sheet 30 includes a third covering portion c and a third attaching portion 33. The third covering portion c includes a fifth sub-covering portion 31 and a sixth sub-covering portion 32. The third attaching portion 33 is located between and connected to the fifth sub-covering portion 31 and the sixth sub-covering portion 32. A seventh fold 107 is formed between the third attaching portion 33 and the fifth sub-covering portion 31, and the third attaching portion 33 and the fifth sub-covering portion 31 can be bent relative to each other about the seventh fold 107. An eighth fold 108 is formed between the third attaching portion 33 and the sixth sub-covering portion 32, and the third attaching portion 33 and the sixth sub-covering portion 32 can be bent relative to each other about the eighth fold 108. In this embodiment, the third attaching portion 33 is a rectangular sheet. The fifth sub-covering portion 31 and the sixth sub-covering portion 32 are both isosceles trapezoidal sheets.

[0081] In one embodiment, the fifth sub-covering portion 31 includes one or more vent holes Q. For ease of description, the vent hole Q on the fifth sub-covering portion 31 is named the fifth vent hole Q5. The fifth vent hole Q5 is used for the passage of gas generated by the power core 400 in the event of thermal runaway. The fifth vent hole Q5 can be, but is not limited to, a through hole of regular or irregular shape such as a circular hole, a triangular hole, a rectangular hole, or an oblong hole. When there are multiple fifth vent holes Q5, all of them penetrate both surfaces of the fifth sub-covering portion 31 in the thickness direction. The multiple fifth vent holes Q5 can be arranged in a straight line, a matrix, or a serpentine pattern along the length direction (i.e., the Z-axis direction) of the fifth sub-covering portion 31. Adjacent fifth vent holes Q5 are spaced apart or tangentially arranged. The shapes of the multiple fifth vent holes Q5 can be the same or different. For example, the number of fifth vent holes Q5 is one, and its shape is a circular hole.

[0082] In one embodiment, the sixth sub-covering portion 32 includes one or more vent holes Q. For ease of description, the vent hole Q on the sixth sub-covering portion 32 is named the sixth vent hole Q6. The sixth vent hole Q6 is used for the passage of gas generated by the power core 400 in the event of thermal runaway. The sixth vent hole Q6 can be, but is not limited to, a through hole of regular or irregular shape such as a circular hole, a triangular hole, a rectangular hole, or an oblong hole. When there are multiple sixth vent holes Q6, all of them penetrate both surfaces of the sixth sub-covering portion 32 in the thickness direction. The multiple sixth vent holes Q6 can be arranged in a straight line, a matrix, or a serpentine pattern along the length direction (i.e., the Z-axis direction) of the sixth sub-covering portion 32. Adjacent sixth vent holes Q6 are spaced apart or tangentially arranged. The shapes of the multiple sixth vent holes Q6 can be the same or different. For example, the number of sixth vent holes Q6 is one, and its shape is a circular hole.

[0083] It is understood that the insulating film 100 may include at least one of the following: a first vent Q1, a second vent Q2, a third vent Q3, a fourth vent Q4, a fifth vent Q5, or a sixth vent Q6. That is, the vent Q may be provided in at least one of the first sub-covering portion 11, the second sub-covering portion 12, the third sub-covering portion 21, the fourth sub-covering portion 22, the fifth sub-covering portion 31, and the sixth sub-covering portion 32, as long as it satisfies the requirement for smooth venting of the battery cell 400 under thermal runaway. Furthermore, the structure of the insulating film 100 is not limited to the structure described in this embodiment, as long as the insulating film 100 has an overlapping region M and vent Q is provided within the overlapping region M to meet the requirement for smooth venting of the battery cell 400 and to insulate the battery cell 400 from the outer casing 200. This application does not impose any limitations on this.

[0084] In this embodiment, as Figure 5 As shown, in the flattened state, the third attachment portion 33 of the bottom sheet 30 is connected to the first attachment portion 13 of the first sheet 10 and the second attachment portion 23 of the second sheet 20. The fifth sub-covering portion 31 of the bottom sheet 30, the first sub-covering portion 11 of the first sheet 10, and the third sub-covering portion 21 of the second sheet 20 are located on the same side of the insulating film 100 in the Y-axis direction and are spaced apart from each other. The sixth sub-covering portion 32 of the bottom sheet 30, the second sub-covering portion 12 of the first sheet 10, and the fourth sub-covering portion 22 of the second sheet 20 are located on the other side of the insulating film 100 in the Y-axis direction and are spaced apart from each other. The fifth sub-covering portion 31 and the first sub-covering portion 11 are arranged at an angle to each other on their opposite sides, and the sixth sub-covering portion 32 and the second sub-covering portion 12 are also arranged at an angle to each other on their opposite sides. This facilitates the folding of the bottom sheet 30 and the first sheet 10 and prevents interference when the bottom sheet 30 and the first sheet 10 are folded. The fifth sub-covering portion 31 and the third sub-covering portion 21 are arranged at an angle to each other on their opposite sides, and the sixth sub-covering portion 32 and the fourth sub-covering portion 22 are also arranged at an angle to each other on their opposite sides. This facilitates the folding of the bottom sheet 30 and the second sheet 20 and prevents interference when the bottom sheet 30 and the second sheet 20 are folded.

[0085] like Figure 4 As shown, in the folded state, the insulating film 100, the first sheet 10, the second sheet 20, and the bottom sheet 30 together form a receiving groove 120. The sides of the first sheet 10 and the second sheet 20 away from the bottom sheet 30 form a through-hole 110, which communicates with the receiving groove 120. The receiving groove 120 is used to receive the battery cell 400. The through-hole 110 is used to expose the battery cell 400. The insulating film 100 has an overlapping region M. The overlapping region M is positioned opposite to the side 407 of the battery cell 400.

[0086] Specifically, the first attachment portion 13 of the first sheet 10 and the second attachment portion 23 of the second sheet 20 are respectively angled to the first attachment portion 13 of the bottom sheet 30, and the first attachment portion 13 and the second attachment portion 23 are positioned opposite each other and spaced apart along the X-axis. The first sub-covering portion 11 and the second sub-covering portion 12 of the first sheet 10 are both angled to the first attachment portion 13, and the first sub-covering portion 11 and the second sub-covering portion 12 are positioned opposite each other and spaced apart along the Y-axis. The third sub-covering portion 21 and the fourth sub-covering portion 22 of the second sheet 20 are both angled to the second attachment portion 23, and the third sub-covering portion 21 and the fourth sub-covering portion 22 are positioned opposite each other and spaced apart along the Y-axis. The fifth sub-covering portion 31 and the sixth sub-covering portion 32 of the bottom sheet 30 are both angled to the third attachment portion 33, and the fifth sub-covering portion 31 and the sixth sub-covering portion 32 are positioned opposite each other and spaced apart along the Y-axis. The first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31 are stacked and have an overlapping area M. The second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32 are stacked and have an overlapping area M.

[0087] Please refer to the following: Figure 4 , Figure 6 and Figure 7 , Figure 6 for Figure 4 The image shown is a left perspective view of the first embodiment of the insulating film in a folded state. Figure 7 for Figure 4 The image shows a right-side perspective view of the first embodiment of the insulating film in a folded state.

[0088] like Figure 4 and Figure 6 As shown, the first sub-covering portion 11 and the third sub-covering portion 21 partially overlap in the Y-axis direction. The first sub-covering portion 11 and the third sub-covering portion 21 each partially overlap with the fifth sub-covering portion 31 in the Y-axis direction, and the overlapping portion of the first sub-covering portion 11 and the third sub-covering portion 21 partially overlaps with the fifth sub-covering portion 31. Along the Y-axis direction, the fifth sub-covering portion 31 is located on the side of the first sub-covering portion 11 and the third sub-covering portion 21 facing away from the bottom sheet 30. It can be understood that the first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31 overlap in pairs, and the first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31 have simultaneously overlapping portions.

[0089] In this embodiment, the overlapping region M includes a first overlapping region M1 and a second overlapping region M2. The first overlapping region M1 and the second overlapping region M2 are arranged opposite to the first side surface 401 of the battery cell 400, and are sequentially arranged along the Z-axis. The overlapping region M where the first sub-covering portion 11 and the third sub-covering portion 21 overlap simultaneously but are not covered by the fifth sub-covering portion 31 is called the first overlapping region M1, and the overlapping region M where the first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31 overlap simultaneously is called the second overlapping region M2. It can be understood that the first overlapping region M1 is formed by stacking two thin sheets, and the second overlapping region M2 is formed by stacking three thin sheets.

[0090] In this embodiment, the vent Q (i.e., the fifth vent Q5) of the fifth sub-covering portion 31 is located within the second overlapping region M2. The plurality of vent Q (i.e., the first vent Q1) of the first sub-covering portion 11 and the plurality of vent Q (i.e., the third vent Q3) of the third sub-covering portion 21 are both located within the first overlapping region M1. The plurality of first vent Q1 and the plurality of third vent Q3 are completely staggered, that is, the plurality of first vent Q1 and the plurality of third vent Q3 do not overlap at all in the Y-axis direction. Along the Y-axis direction, the projections of the plurality of first vent Q1 and the projections of the plurality of third vent Q3 are spaced apart or tangentially arranged to avoid overlapping portions of the first vent Q1 and the third vent Q3, thus exposing the first side 401 of the covered battery cell 400, and thereby avoiding affecting the insulation performance of the insulating film 100. For example, a plurality of first exhaust holes Q1 and a plurality of third exhaust holes Q3 are arranged in a straight line along the Z-axis direction, and the plurality of first exhaust holes Q1 and a plurality of third exhaust holes Q3 are alternately spaced apart from each other.

[0091] like Figure 4 and Figure 7 As shown, the second sub-covering portion 12 and the fourth sub-covering portion 22 partially overlap in the Y-axis direction. The second sub-covering portion 12 and the fourth sub-covering portion 22 also partially overlap with the sixth sub-covering portion 32 in the Y-axis direction, and the overlapping portion of the second sub-covering portion 12 and the fourth sub-covering portion 22 partially overlaps with the sixth sub-covering portion 32. Along the Y-axis direction, the sixth sub-covering portion 32 is located on the side of the second sub-covering portion 12 and the fourth sub-covering portion 22 facing away from the bottom sheet 30. It can be understood that the second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32 overlap in pairs, and that the second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32 have simultaneously overlapping portions.

[0092] In this embodiment, the overlapping region M further includes a third overlapping region M3 and a fourth overlapping region M4. The third overlapping region M3 and the fourth overlapping region M4 are arranged opposite to the second side surface 402 of the battery cell 400, and are sequentially arranged along the Z-axis. The overlapping region M where the second sub-covering portion 12 and the fourth sub-covering portion 22 overlap simultaneously but are not covered by the sixth sub-covering portion 32 is called the third overlapping region M3, and the overlapping region M where the second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32 overlap simultaneously is called the fourth overlapping region M4. It can be understood that the third overlapping region M3 is formed by stacking two thin sheets, and the fourth overlapping region M4 is formed by stacking three thin sheets.

[0093] The vent Q (i.e., the sixth vent Q6) of the sixth sub-covering portion 32 is located within the fourth overlapping region M4. The plurality of vent Q (i.e., the second vent Q2) of the second sub-covering portion 12 and the plurality of vent Q (i.e., the fourth vent Q4) of the fourth sub-covering portion 22 are both located within the third overlapping region M3. The plurality of second vent Q2 and the plurality of fourth vent Q4 are completely staggered, that is, the plurality of second vent Q2 and the plurality of fourth vent Q4 do not overlap at all in the Y-axis direction. Along the Y-axis direction, the projections of the plurality of second vent Q2 and the plurality of fourth vent Q4 are spaced apart or tangentially arranged to avoid overlapping portions of the second vent Q2 and the fourth vent Q4, thus exposing the second side 402 of the covered battery cell 400 and preventing any impact on the insulation performance of the insulating film 100. For example, a plurality of second exhaust holes Q2 and a plurality of fourth exhaust holes Q4 are arranged in a straight line along the Z-axis direction, and the plurality of second exhaust holes Q2 and a plurality of fourth exhaust holes Q4 are alternately spaced apart from each other.

[0094] Furthermore, the first covering portion a, the second covering portion b, and the third attaching portion 33 on the same side form a notch 130, and the third covering portion c completely covers the notch 130 to avoid exposing the surface of the battery cell 400 and to prevent the battery cell 400 from conducting with the outer casing 200. Figure 6 and Figure 7As shown, along the Z-axis, the side of the first sub-covering portion 11 facing away from the through-hole 110, the side of the third sub-covering portion 21 facing away from the through-hole 110, and the third attachment portion 33 form a notch 130, which is referred to as the first notch 130a. The fifth sub-covering portion 31 completely covers the first notch 130a, and the fifth sub-covering portion 31 partially covers the first side 401 of the battery cell 400 to avoid exposing the first side 401 of the battery cell 400 and to prevent the battery cell 400 and the outer casing 200 from conducting. Along the Z-axis, the side of the second sub-covering portion 12 facing away from the through-hole 110, the side of the fourth sub-covering portion 22 facing away from the through-hole 110, and the third attachment portion 33 form a notch 130, which is referred to as the second notch 130b. The sixth sub-covering portion 32 completely covers the second notch 130b, and the sixth sub-covering portion 32 partially covers the second side 402 of the battery cell 400 to avoid exposing the second side 402 of the battery cell 400 and to prevent the battery cell 400 and the outer casing 200 from conducting.

[0095] Please refer to the following: Figure 4 , Figure 8 and Figure 9 , Figure 8 for Figure 4 The image shown is a left perspective view of the second embodiment of the insulating film in a folded state. Figure 9 for Figure 4 The right-side perspective view of the second embodiment of the insulating film in a folded state.

[0096] In this embodiment, unlike the structure of the insulating film in the first embodiment described above, the vent holes Q (i.e., the first vent hole Q1) of the first sub-covering portion 11 and Q (i.e., the third vent hole Q3) of the third sub-covering portion 21 are located not only within the first overlapping area M1 but also within the second overlapping area M2, and the fifth sub-covering portion 31 does not have vent holes Q. The fifth sub-covering portion 31 completely covers the first vent hole Q1 and the second vent hole Q2. Along the Y-axis direction, the projections of the first vent hole Q1 and the third vent hole Q3 are both within the projection range of the fifth sub-covering portion 31. When the insulating film 100 covers the battery cell 400, this prevents the first vent holes Q1 and the third vent holes Q3 from being exposed on the first side 401 of the covered battery cell 400, preventing the battery cell 400 from conducting with the outer casing 200, thereby avoiding affecting the insulation performance of the insulating film 100; at the same time, the absence of vent holes Q in the fifth sub-covering portion 31 further enhances the insulation reliability of the insulating film 100.

[0097] In some embodiments, the second overlapping area M2 includes only the first exhaust port Q1 or the second exhaust port Q2.

[0098] The vent Q of the second sub-covering portion 12 (i.e., the second vent Q2) and the vent Q of the fourth sub-covering portion 22 (i.e., the fourth vent Q4) can be located not only within the third overlapping region M3 but also within the fourth overlapping region M4, and the sixth sub-covering portion 32 does not have a vent Q. The sixth sub-covering portion 32 completely covers the second vent Q2 and the fourth vent Q4. Along the Y-axis direction, the projections of the second vent Q2 and the fourth vent Q4 are both located within the projection of the sixth sub-covering portion 32. When the insulating film 100 covers the battery cell 400, this prevents the second vent Q2 and the fourth vent Q4 from being exposed on the second side 402 of the covered battery cell 400, preventing the battery cell 400 from conducting with the outer casing 200, thereby avoiding affecting the insulation performance of the insulating film 100; at the same time, the absence of a vent Q in the sixth sub-covering portion 32 further enhances the insulation reliability of the insulating film 100.

[0099] In some embodiments, the fourth overlapping region M4 includes only the second exhaust port Q2 or the fourth exhaust port Q4.

[0100] Please combine participation Figure 4 , Figure 10 and Figure 11 , Figure 10 for Figure 4 The image shown is a left perspective view of the third embodiment of the insulating film in a folded state. Figure 11 for Figure 4 The right-side perspective view of the third embodiment of the insulating film in a folded state.

[0101] In this embodiment, unlike the insulating film structure in the second embodiment described above, the fifth sub-covering portion 31 is provided with an exhaust hole Q (i.e., the fifth exhaust hole Q5), and the fifth exhaust hole Q5 is located within the second overlapping area M2. At least two of the exhaust holes of the first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31 are completely staggered. That is, at least two of the first exhaust hole Q1, the third exhaust hole Q3, and the fifth exhaust hole Q5 do not overlap in the Y-axis direction.

[0102] For example, such as Figure 4 and Figure 10 As shown, the first vent Q1, the third vent Q3, and the fifth vent Q5 do not overlap at all in the Y-axis direction. Along the Y-axis direction, the projections of the first vent Q1, the third vent Q3, and the fifth vent Q5 are spaced apart or tangentially arranged to avoid overlapping portions of the first vent Q1, the third vent Q3, and the fifth vent Q5, thus exposing the first side 401 of the covered battery cell 400 and thus avoiding affecting the insulation performance of the insulating film 100.

[0103] In some embodiments, along the Y-axis direction, the projections of the first vent Q1 of the first sub-covering portion 11, the third vent Q3 of the third sub-covering portion 21, and the fifth vent Q5 may have overlapping portions, as long as the thickness of the insulating film 100 in the first overlapping region M1 and the second overlapping region M2 is sufficient to separate and insulate the cell 400 and the housing 200.

[0104] The sixth sub-covering portion 32 is provided with an exhaust hole Q (i.e., the fifth exhaust hole Q5), and the sixth exhaust hole Q6 is located within the fourth overlapping area M4. At least two of the exhaust holes of the second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32 are completely staggered. That is, at least two of the second exhaust hole Q2, the fourth exhaust hole Q4, and the sixth exhaust hole Q6 do not overlap in the Y-axis direction.

[0105] For example, such as Figure 4 and Figure 11 As shown, the second vent Q2 and the fourth vent Q4 do not overlap with the sixth vent Q6 in the Y-axis direction. Along the Y-axis direction, the projections of the second vent Q2, the fourth vent Q4, and the sixth vent Q6 are spaced apart or tangentially arranged to avoid overlapping portions of the second vent Q2, the fourth vent Q4, and the sixth vent Q6, thus exposing the second side 402 of the covered battery cell 400 and thus avoiding affecting the insulation performance of the insulating film 100.

[0106] In some embodiments, along the Y-axis direction, the projections of the second vent Q2 of the second sub-covering portion 12, the fourth vent Q4 of the fourth sub-covering portion 22, and the sixth vent Q6 may have overlapping portions, as long as the thickness of the insulating film 100 in the third overlapping region M3 and the fourth overlapping region M4 is sufficient to separate and insulate the cell 400 and the housing 200.

[0107] Please refer to it again. Figure 2 and Figure 3 .

[0108] In this embodiment, the end cap assembly 300 is mounted on the top of the battery cell 400. The battery cell 400 is housed within the receiving groove 120 of the insulating film 100. The first side 401 of the battery cell 400 is covered by the first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31 of the insulating film 100. The second side 402 of the battery cell 400 is covered by the second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32 of the insulating film 100. The bottom surface 405 of the battery cell 400 is covered by the third attachment portion 33 of the insulating film 100. The first surface 403 of the battery cell 400 is covered by the first attachment portion 13 of the insulating film 100. The second surface 404 of the battery cell 400 is covered by the second attachment portion 23 of the insulating film 100; the battery cell 400, the end cap assembly 300, and the insulating film 100 are housed together in the receiving cavity of the housing 200. The insulating film 100 separates and insulates the battery cell 400 from the housing 200, preventing the battery cell 400 from contacting the housing 200 and causing a short circuit. The end cap assembly 300 is sealed to the opening 201 of the housing 200.

[0109] Taking the insulating film 100 in the first embodiment as an example, the coating process of the insulating film 100 and the battery cell 400 is described as follows:

[0110] The insulating film 100 is flattened and located at the bottom of the battery cell 400. The third attachment portion 33 of the bottom sheet 30 faces and covers the bottom surface 405 of the battery cell 400. Along the Z-axis, the projection of the bottom surface 405 of the battery cell 400 lies within the projection of the third attachment portion 33. The first sheet 10 and the second sheet 20 are bent relative to each other about the first crease 101 and the second crease 102, respectively, and the first sheet 10 and the second sheet 20 are located on opposite sides of the width direction of the battery cell 400. The first attachment portion 13 of the first sheet 10 faces and covers the first surface 403 of the battery cell 400. The second attachment portion 23 of the second sheet 20 faces and covers the second surface 404 of the battery cell 400. Along the X-axis, the projection of the first surface 403 of the battery cell 400 lies within the projection of the first attachment portion 13, and the projection of the second surface 404 of the battery cell 400 lies within the projection of the second attachment portion 23. Specifically, the first crease 101 and the boundary between the first surface 403 and the bottom surface 405 of the battery cell 400 are opposite each other, and the second crease 102 and the boundary between the second surface 404 and the bottom surface 405 of the battery cell 400 are opposite each other.

[0111] The first sub-covering portion 11 and the second sub-covering portion 12 of the first sheet 10 are bent relative to each other about the third crease 103 and the fourth crease 104, respectively, and the first sub-covering portion 11 and the second sub-covering portion 12 are located on opposite sides of the width direction of the cell 400. The first sub-covering portion 11 is opposite to the first side surface 401 of the cell 400 and covers a portion of the first side surface 401 of the cell 400. The second sub-covering portion 12 is opposite to the second side surface 402 of the cell 400 and covers a portion of the second side surface 402 of the cell 400. Along the Y-axis direction, the projection of the first sub-covering portion 11 is completely within the projection of the first side surface 401, and the projection of the second sub-covering portion 12 is completely within the projection of the second side surface 402. The third crease 103 is opposite to the boundary between the first surface 403 and the first side surface 401 of the cell 400, and the fourth crease 104 is opposite to the boundary between the first surface 403 and the second side surface 402 of the cell 400.

[0112] The third sub-covering portion 21 and the fourth sub-covering portion 22 of the second sheet 20 are bent relative to each other about the fifth crease 105 and the sixth crease 106, respectively, and are located on opposite sides of the cell 400 in the width direction. The third sub-covering portion 21 faces the first side 401 of the cell 400 and covers a portion of the first side 401. The fourth sub-covering portion 22 faces the second side 402 of the cell 400 and covers a portion of the second side 402. Along the Y-axis, the projection of the third sub-covering portion 21 is completely within the projection of the first side 401, and the projection of the fourth sub-covering portion 22 is completely within the projection of the second side 402. The fifth crease 105 faces the boundary between the second surface 404 and the first side 401 of the cell 400, and the sixth crease 106 faces the boundary between the second surface 404 and the second side 402 of the cell 400.

[0113] The fifth sub-covering portion 31 and the sixth sub-covering portion 32 of the bottom sheet 30 are bent relative to each other about the seventh crease 107 and the eighth crease 108, respectively, and are located on opposite sides of the cell 400 in the width direction. The fifth sub-covering portion 31 faces the first side 401 of the cell 400 and covers a portion of the first side 401. The sixth sub-covering portion 32 faces the second side 402 of the cell 400 and covers a portion of the second side 402. Along the Y-axis, the projection of the fifth sub-covering portion 31 is completely within the projection of the first side 401, and the projection of the sixth sub-covering portion 32 is completely within the projection of the second side 402. Among them, the seventh crease 107 is opposite to the boundary between the bottom surface 405 and the first side surface 401 of the battery cell 400, and the eighth crease 108 is opposite to the boundary between the bottom surface 405 and the second side surface 402 of the battery cell 400.

[0114] In this embodiment, the third sub-covering portion 21 is located between the first sub-covering portion 11 and the fifth sub-covering portion 31, and the fifth sub-covering portion 31 is located on the side of the third sub-covering portion 21 and the first sub-covering portion 11 facing away from the cell 400. The third sub-covering portion 21 and the first sub-covering portion 11 are at least partially connected and fixed by means not limited to heat fusion or adhesive bonding. The fifth sub-covering portion 31 and the first sub-covering portion 11 are at least partially connected and fixed to the third sub-covering portion 21 by means not limited to heat fusion or adhesive bonding. In some embodiments, depending on the process, the first sub-covering portion 11 may also be located between the third sub-covering portion 21 and the fifth sub-covering portion 31. This application does not limit this.

[0115] In this embodiment, the fourth sub-covering portion 22 is located between the second sub-covering portion 12 and the sixth sub-covering portion 32, and the sixth sub-covering portion 32 is located on the side of the fourth sub-covering portion 22 and the second sub-covering portion 12 facing away from the cell 400. The fourth sub-covering portion 22 and the second sub-covering portion 12 are at least partially connected and fixed by means not limited to heat fusion or adhesive bonding. The sixth sub-covering portion 32 and the second sub-covering portion 12 are at least partially connected and fixed to the third sub-covering portion 21 by means not limited to heat fusion or adhesive bonding. In some embodiments, depending on the process, the second sub-covering portion 12 may also be located between the fourth sub-covering portion 22 and the fifth sub-covering portion 31. This application does not limit this.

[0116] In related technologies, secondary batteries typically employ an insulating sheet between the battery cell and the metal casing. This insulating sheet covers the battery cell, separating and insulating it from the metal casing. However, in practical applications, to achieve high energy density, the core within the battery cell is often large, resulting in a very small gap between the core and the casing. Furthermore, existing insulating sheets cover only the surface of the battery cell. When thermal runaway occurs in the battery cell, generating a large amount of gas, the gas can only escape from the top of the cell, which is not covered by the insulating sheet. This hinders the venting of gas from the sides of the battery, preventing rapid gas discharge. If gas accumulates inside the secondary battery, it can easily cause safety issues such as casing rupture, thus affecting the safety performance of the secondary battery.

[0117] In this embodiment, the insulating film 100 has a plurality of vent holes Q in the first overlapping area M1 of the first sub-covering portion 11 and the third sub-covering portion 21, and vent holes Q are also provided in the second overlapping area M2 of the first sub-covering portion 11, the third sub-covering portion 21, and the fifth sub-covering portion 31. The plurality of vent holes Q are spaced apart from each other or tangentially arranged. Furthermore, the insulating film 100 has a plurality of vent holes Q in the third overlapping area M3 of the second sub-covering portion 12 and the fourth sub-covering portion 22, and vent holes Q are also provided in the fourth overlapping area M4 of the second sub-covering portion 12, the fourth sub-covering portion 22, and the sixth sub-covering portion 32. The plurality of vent holes Q are spaced apart from each other or tangentially arranged.

[0118] During the operation of the energy storage device 1000, if the battery cell 400 experiences thermal runaway, it will generate a large amount of gas. The gas in the battery cell 400 can not only be discharged through the perforation 110 of the insulating film 100, but also cause the insulating film 100 to expand in the direction away from the battery cell 400 and be discharged through multiple exhaust holes Q provided in the lamination gaps and overlapping areas M of the insulating film 100.

[0119] Specifically, the gap between the first sub-covering portion 11 and the first side surface 401 of the cell 400 is opened by gas, and the gap between the first sub-covering portion 11, the third sub-covering portion 21 and the fifth sub-covering portion 31 is also opened by gas. Gas can be discharged from the gap between the first sub-covering portion 11 and the first side surface 401 of the cell 400, or it can be discharged from the gap between the first sub-covering portion 11 and the third sub-covering portion 21 through the first exhaust port Q1, or it can be discharged from the third sub-covering portion 21 through the third exhaust port Q3, or it can be discharged from the gap between the fifth sub-covering portion 31 and the first sub-covering portion 11, the second sub-covering portion 12 and the first side surface 401 of the cell 400, or it can be discharged from the fifth sub-covering portion 31 through the fifth exhaust port Q5. Simultaneously, the gap between the second sub-covering portion 12 and the second side surface 402 of the cell 400 is opened by gas, and the gap between the second sub-covering portion 12, the fourth sub-covering portion 22 and the sixth sub-covering portion 32 is also opened by gas. Gas can be discharged from the gap between the second sub-covering portion 12 and the second side surface 402 of the cell 400, or it can be discharged from the gap between the second sub-covering portion 12 and the fourth sub-covering portion 22 through the second exhaust port Q2, or it can be discharged from the fourth sub-covering portion 22 through the fourth exhaust port Q4, or it can be discharged from the sixth sub-covering portion 32 through the gap between the second sub-covering portion 12, the fourth sub-covering portion 22 and the second side surface 402 of the cell 400, or it can be discharged from the sixth sub-covering portion 32 through the sixth exhaust port Q6.

[0120] It is understood that the gas generated by the battery cell 400 is discharged through the gaps between the first sub-covering portion 11, the third sub-covering portion 21 and the fifth sub-covering portion 31 on the side of the insulating film 100, the gaps between the second sub-covering portion 12, the fourth sub-covering portion 22 and the sixth sub-covering portion 32, and the multiple vent holes Q provided on these sub-covering portions. The gas discharged through the side of the insulating film 100 and the gas discharged through the throughlet 110 of the insulating film 100 converge at the top of the outer casing 200 and is depressurized through the end cap assembly 300 connected to the opening 201 of the outer casing 200. The vent holes Q are opened in the overlapping area M on the side of the insulating film 100, which accelerates the exhaust speed of the battery cell 400 under thermal runaway, improves the exhaust effect of the battery cell 400 when thermal runaway occurs, avoids the accumulation of gas generated by the battery cell 400 inside the energy storage device 1000 and avoids causing safety hazards to the energy storage device 1000, and ensures the safety performance of the energy storage device 1000.

[0121] Furthermore, the vent holes Q on the first sub-covering part 11, the third sub-covering part 21, and the fifth sub-covering part 31 can be completely non-overlapping, and the vent holes Q on the second sub-covering part 12, the fourth sub-covering part 22, and the sixth sub-covering part 32 can also be completely non-overlapping. This not only ensures that the insulating film 100 does not leak the internal battery cell 400, thus completely separating and insulating the battery cell 400 from the outer casing 200 and ensuring the insulation performance of the insulating film 100, but also does not affect the gas from the battery cell 400 from the vent holes Q opened on the side of the insulating film 100, thereby further improving the safety performance of the energy storage device 1000.

[0122] The third sub-covering part 21, together with the first sub-covering part 11 and the third attachment part 33, forms a first notch 130a. The first notch 130a exposes part of the first side 401 of the battery cell 400. The fifth sub-covering part 31 is located on the side of the third sub-covering part 21 and the first sub-covering part 11 facing away from the battery cell 400, and covers the first notch 130a, so that a portion of the gas generated by the battery cell 400 can pass directly through the first notch 130a and be discharged through the gap between the fifth sub-covering part 31 and the third sub-covering part 21 and the first sub-covering part 11, as well as the fifth exhaust hole Q5 on the fifth sub-covering part 31. The fourth sub-covering portion 22, together with the second sub-covering portion 12 and the third attachment portion 33, forms the second notch 130b. The sixth sub-covering portion 32 is located on the side of the fourth sub-covering portion 22 and the second sub-covering portion 12 facing away from the cell 400, and covers the second notch 130b, so that a portion of the gas generated by the cell 400 can directly pass through the second notch 130b and be discharged through the gap between the sixth sub-covering portion 32 and the fourth sub-covering portion 22 and the second sub-covering portion 12, as well as the sixth exhaust port Q6 on the sixth sub-covering portion 32; thereby shortening the gas discharge path and further improving the exhaust efficiency.

[0123] The above are merely some embodiments and implementation methods of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An insulating film for insulating battery cells, characterized in that, The insulating film includes vent holes that penetrate both surfaces of the insulating film in the thickness direction. The insulating film has an overlapping area, and the vent holes are located within the overlapping area of ​​the insulating film.

2. The insulating film according to claim 1, characterized in that, The battery cell includes a first side and a second side, wherein the first side and the second side are arranged opposite to each other along the length direction of the battery cell; The overlapping area includes a first overlapping area, a second overlapping area, a third overlapping area, and a fourth overlapping area. The first overlapping area and the second overlapping area are both used to cover the first side of the battery cell, and the first overlapping area and the second overlapping area are arranged sequentially in the height direction of the battery cell. The third overlapping area and the fourth overlapping area are both used to cover the second side of the battery cell, and the third overlapping area and the fourth overlapping area are arranged sequentially in the height direction of the battery cell. The vent is disposed in at least one of the first overlapping area, the third overlapping area, the second overlapping area, and the fourth overlapping area.

3. The insulating film according to claim 2, characterized in that, The insulating film further includes a first sheet, a second sheet, and a bottom sheet. The bottom sheet is connected to the first sheet and the second sheet, and the first sheet and the second sheet are stacked on the first side and the second side to form a first overlapping area and a third overlapping area. The bottom sheet is stacked on the first side and the second sheet, respectively, on the first side and the second side, and the bottom sheet has a portion that overlaps with the first sheet and the second sheet to form a second overlapping area and a fourth overlapping area. The vent is provided in at least one of the first sheet, the second sheet, and the bottom sheet.

4. The insulating film according to claim 3, characterized in that, The vent is disposed in at least one of the first sheet and the second sheet, and the vent is located in the first overlapping area and / or the third overlapping area.

5. The insulating film according to claim 4, characterized in that, Both the first sheet and the second sheet are provided with the vent holes in the first overlapping area, and the vent holes of the first sheet and the second sheet do not overlap in the first overlapping area. And / or, both the first sheet and the second sheet are provided with the vent holes in the third overlapping area, and the vent holes of the first sheet and the second sheet do not overlap in the third overlapping area.

6. The insulating film according to claim 4 or 5, characterized in that, The vent is also located within the second overlapping region and / or the fourth overlapping region.

7. The insulating film according to claim 6, characterized in that, The vent is also provided on the bottom sheet; Within the second overlapping region and / or the fourth overlapping region, the vent holes on at least two of the bottom sheet, the first sheet, and the second sheet do not overlap.

8. The insulating film according to claim 3, characterized in that, The battery cell further includes a first surface, a second surface, and a bottom surface. The first surface and the second surface are arranged opposite to each other along the width direction of the battery cell and are connected to the first side surface and the second side surface. The bottom surface is a surface in the height direction of the battery cell and is connected to the first surface, the second surface, the first side surface, and the second side surface. The first sheet includes a first attachment portion and two first covering portions connected to both sides of the first attachment portion. The two first covering portions are respectively used to cover at least a portion of the first side and the second side of the battery cell. The second sheet includes a second attachment portion and two second covering portions connected to both sides of the second attachment portion. The two second covering portions are respectively used to cover at least a portion of the first side and the second side of the battery cell. The bottom sheet includes a third attachment portion and two third covering portions connected to both sides of the third attachment portion. The two third covering portions respectively cover at least a portion of the first side and the second side of the battery cell. The third attachment portion is connected to the first attachment portion and the second attachment portion. The first attachment portion is used to cover the first surface of the battery cell, the second attachment portion is used to cover the second surface of the battery cell, and the third attachment portion is used to cover the bottom surface of the battery cell. The two first covering portions are respectively stacked with the second covering portion on the same side, forming the first overlapping area and the third overlapping area respectively. The two third covering portions are simultaneously stacked with the first covering portion and the second covering portion on the same side, forming the second overlapping area and the fourth overlapping area respectively.

9. The insulating film according to claim 8, characterized in that, In the height direction of the battery cell, the first covering portion and the second covering portion on the same side form a notch with the third attachment portion, and the third covering portion covers the notch.

10. The insulating film according to claim 8, characterized in that, Along the length of the battery cell, the third covering portion is located on the side opposite to the first covering portion and the second covering portion on the same side of the battery cell.

11. The insulating film according to claim 8, characterized in that, Along the length of the battery cell, the first covering portion, the second covering portion, and the third covering portion on the same side are at least partially connected and fixed by heat fusion or adhesive bonding.

12. The insulating film according to claim 1, characterized in that, The number of exhaust holes is multiple, and the multiple exhaust holes are arranged in a straight line, in a serpentine pattern, or in a matrix.

13. An energy storage device, characterized in that, The energy storage device includes a housing, a battery cell, an end cap assembly, and an insulating film as described in any one of claims 1-12. The battery cell and the insulating film are both housed within the housing. The insulating film is located between the battery cell and the housing and covers the battery cell. The end cap assembly is housed within the battery cell and sealed to the housing.

14. An energy storage system, characterized in that, The energy storage system includes the energy storage device as described in claim 13.

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