Insulating film, battery cell, battery, and electric device

Abstract

Provided in the embodiments of the present disclosure are an insulating film, a battery cell, a battery, and an electric device. The battery cell comprises an electrode assembly, a casing and an insulating film. The electrode assembly comprises a plurality of surfaces, the plurality of surfaces comprising a first surface, which is the surface with the largest area among the plurality of surfaces. The casing forms an accommodating space for accommodating the electrode assembly. The insulating film wraps around the periphery of the electrode assembly and is located between the electrode assembly and the casing, and the insulating film has a first thickness area and a second thickness area, wherein the thickness of the first thickness area is greater than that of the second thickness area, and the first thickness area is located in the area where the first surface of the electrode assembly is located.

Description

Insulating film, battery cell, battery and electrical equipment

[0001] Cross-references to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202420879523.7, filed on April 25, 2024, entitled "Insulating Film, Battery Cell, Battery and Electrical Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of battery technology, and in particular to insulating films, battery cells, batteries and electrical devices. Background Technology

[0004] This section is intended to provide background or context for embodiments of this disclosure. The description herein is not intended to imply that it is prior art simply because it is included in this section.

[0005] During battery assembly, after the bare cells are assembled, there is a casing process. When placing the bare cells into the casing, a Mylar film, also known as a Mylar membrane, is applied to the outer surface of the bare cells to protect them and provide insulation. In related technologies, during battery charging and discharging, the bare cells expand, making it easy for the larger surface area of ​​the bare cells to come into contact with the casing, while the sides of the bare cells are less likely to come into contact with the casing. In the event of thermal runaway inside the bare cells, heat is more easily transferred to the larger surface area of ​​the aluminum casing, resulting in poor heat insulation.

[0006] Summary of the Invention

[0007] In view of this, the present disclosure aims to provide an insulating film, a battery cell, a battery, and an electrical device that can improve the heat insulation effect.

[0008] Therefore, a first aspect of the present disclosure provides a battery cell, comprising:

[0009] An electrode assembly includes multiple surfaces, including a first surface, which is the surface with the largest area among the multiple surfaces.

[0010] The housing forms a space for accommodating the electrode assembly;

[0011] An insulating film is wrapped around the outer periphery of the electrode assembly and located between the electrode assembly and the housing. The insulating film has a first thickness region and a second thickness region. The thickness of the first thickness region is greater than the thickness of the second thickness region. The first thickness region is located in the region where the first surface of the electrode assembly is located.

[0012] The battery cell provided in this disclosure includes an electrode assembly and an insulating film. The insulating film has a first thickness region and a second thickness region, with the first thickness region being thicker than the second thickness region. The first thickness region is located on the first surface of the electrode assembly. In other words, the thickness of the insulating film covering at least a portion of the first surface of the electrode assembly is greater than the thickness of the insulating film covering other surfaces of the electrode assembly. This improves the rapid heat transfer to the outer casing when the electrode assembly experiences a short circuit, overcharge, or internal thermal runaway, enhancing the thermal insulation effect of the insulating film and thus improving the reliability of the battery cell.

[0013] In some embodiments, the insulating film is formed by folding a substrate, and the insulating film includes an overlapping region formed by overlapping substrates, the overlapping region constituting a first thickness region.

[0014] In this way, the thickness of the insulating film in the area where the first surface of the electrode assembly is located is greater than the thickness of the insulating film on other surfaces, thereby increasing the thickness of the insulating film between the area where the first surface of the electrode assembly is located and the outer shell, and thus improving the heat insulation effect of the insulating film.

[0015] In some embodiments, the length of the electrode assembly is L0, and the dimension of the first thickness region along the length direction of the electrode assembly is L1, wherein the ratio of L1 to L0 is in the range of 0.8-1.

[0016] While ensuring that the insulating film corresponding to the first surface of the electrode assembly has sufficient structural strength and heat insulation effect, it is possible to avoid affecting the assembly of the battery cells and maintain the structural compactness and performance of the battery cells.

[0017] In some embodiments, the insulating film is formed by folding a substrate, the thickness of which is 0.05mm-0.3mm.

[0018] On the one hand, it can increase the thickness of the insulating film corresponding to the first surface of the electrode assembly, thereby providing better heat insulation and protection. On the other hand, with the same thickness of the insulating film corresponding to the first surface of the electrode assembly, it can reduce the thickness of the insulating film corresponding to the side of the electrode assembly, thereby reducing the cost of the battery.

[0019] In some embodiments, the insulating film is formed by folding a substrate having a first wall thickness region and a second wall thickness region, wherein the thickness of the first wall thickness region is greater than the thickness of the second wall thickness region, and the first wall thickness region is folded to form a first thickness region, and the second wall thickness region is folded to form a second thickness region.

[0020] In this way, the thickness of the insulating film in the area where the first surface of the electrode assembly is located is greater than the thickness of the insulating film on other surfaces, thereby increasing the thickness of the insulating film between the first surface of the electrode assembly and the outer shell, and thus improving the heat insulation effect of the insulating film.

[0021] In some embodiments, the battery cell includes a housing, and an electrode assembly covered with an insulating film is disposed inside the housing, with the distance between the top of the insulating film and the top cover of the housing being 0.1mm-5mm.

[0022] This allows for the connection between the insulating film and the top cover while minimizing the impact on assembling the top cover into the housing.

[0023] In some embodiments, the number of electrode assemblies is one, and the regions where the two first surfaces of the electrode assembly are located are each provided with a first thickness region.

[0024] This further improves the heat insulation and protection effect of the insulating film, and further improves the reliability of the battery cells.

[0025] In some embodiments, the battery cell includes a housing, and an electrode assembly is disposed inside the housing. The number of electrode assemblies is two. The regions where the first surfaces of the two electrode assemblies face away from each other are provided with a first thickness region, while the regions where the first surfaces of the two electrode assemblies face each other are not provided with a first thickness region.

[0026] In this way, while improving the heat insulation and protection effect of the insulating film, the space occupied by the insulating film can also be reduced, which is beneficial to improving the performance of the battery.

[0027] In some embodiments, the insulating film includes a substrate and a sprayed coating layer, wherein a portion of the substrate is provided with the sprayed coating layer to form a first thickness region.

[0028] Here, an insulating coating layer is formed by spraying ceramic or other coatings onto the substrate corresponding to the first surface of the electrode assembly, thereby increasing the thickness of the insulating film corresponding to the first surface of the electrode assembly and improving the heat insulation effect of the insulating film.

[0029] In some embodiments, the insulating film includes a substrate and a coding adhesive, with a portion of the substrate having the coding adhesive to form a first thickness region.

[0030] Here, by setting a coding adhesive on the substrate corresponding to the first surface of the electrode assembly, the thickness of the insulating film corresponding to the first surface of the electrode assembly is increased, thereby improving the heat insulation effect of the insulating film.

[0031] A second aspect of this disclosure provides an insulating film used as the aforementioned battery cell, and the insulating film is used to encapsulate the electrode assembly of the battery cell.

[0032] The insulating film provided in this embodiment has a first thickness region and a second thickness region, where the thickness of the first thickness region is greater than the thickness of the second thickness region. The first thickness region is disposed on the first surface of the electrode assembly. In other words, the thickness of the insulating film covering at least a portion of the first surface of the electrode assembly is greater than the thickness of the insulating film covering other surfaces of the electrode assembly. Therefore, when the electrode assembly experiences a short circuit, overcharge, or internal thermal runaway, it can improve the rapid heat transfer to the outer casing, enhance the thermal insulation effect of the insulating film, and thus improve the reliability of the battery cell.

[0033] In some embodiments, the insulating film is formed by folding a substrate having a bottom covering wall, a first side covering wall, and a second side covering wall, wherein the area of ​​the second side covering wall is larger than the area of ​​the first side covering wall; and when the substrate is in an unfolded state, a first side covering wall is connected to each end of the bottom covering wall along a first direction, and a second side covering wall is connected to each end of each first side covering wall along a second direction, wherein the first direction intersects the second direction.

[0034] By setting the insulating film to overlap at the first surface of the electrode assembly, the thickness of the insulating film between the first surface of the electrode assembly and the housing is increased, thereby improving the heat insulation effect of the insulating film.

[0035] A third aspect of this disclosure provides a battery comprising at least one of the aforementioned battery cells.

[0036] The insulating film of the battery provided in this embodiment has a first thickness region and a second thickness region, wherein the thickness of the first thickness region is greater than the thickness of the second thickness region. The first thickness region is located on the first surface of the electrode assembly. In other words, the thickness of the insulating film covering at least a portion of the first surface of the electrode assembly is greater than the thickness of the insulating film covering the other surfaces of the electrode assembly. Thus, when the electrode assembly experiences a short circuit, overcharge, or internal thermal runaway, the rapid heat transfer to the outer casing can be improved, enhancing the heat insulation and protection effect of the insulating film, thereby improving the reliability of the battery cell.

[0037] A fourth aspect of this disclosure provides an electrical device including the battery described above, the battery being used to provide electrical energy.

[0038] The insulating film of the battery in the electrical device provided in this embodiment of the invention has a first thickness region and a second thickness region, wherein the thickness of the first thickness region is greater than the thickness of the second thickness region. The first thickness region is located in the area where the first surface of the electrode assembly is located. That is, the thickness of the insulating film covering at least a portion of the first surface of the electrode assembly is greater than the thickness of the insulating film covering the other surfaces of the electrode assembly excluding the first surface. In this way, when the electrode assembly experiences a short circuit, overcharge, or internal thermal runaway, the rapid heat transfer to the outer casing can be improved, enhancing the heat insulation and protection effect of the insulating film, thereby improving the reliability of the battery cell. Attached Figure Description

[0039] Figure 1 is a structural schematic diagram of a vehicle provided in an embodiment of this disclosure;

[0040] Figure 2 is a three-dimensional exploded view of a battery provided in an embodiment of this disclosure;

[0041] Figure 3 is a schematic diagram of the structure of a battery cell provided in an embodiment of this disclosure;

[0042] Figure 4 is a three-dimensional exploded view of the battery cell shown in Figure 3;

[0043] Figure 5 is a schematic diagram of the insulating film shown in Figure 4;

[0044] Figure 6 is a schematic diagram of the structure of a substrate in an unfolded state according to an embodiment of the present disclosure.

[0045] Explanation of reference numerals in the attached figures

[0046] 1. Insulating film; 11. Substrate; 111. Second side cover wall; 112. First side cover wall; 113. Bottom cover wall; 2. Electrode assembly; 3. Outer shell; 31. Housing; 32. Top cover; 4. Blue film; 5. Bottom support plate; 6. Adapter; 10. Battery cell; 20. Battery box; 21. First box section; 22. Second box section; 100. Battery; 200. Controller; 300. Motor; 1000. Vehicle. Detailed Implementation

[0047] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this disclosure can be combined with each other, and the detailed descriptions in the specific embodiments should be understood as explanations of the purpose of this disclosure and should not be regarded as undue limitations on this disclosure.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the terms “comprising” and “having” and any variations thereof are intended to cover non-exclusive inclusion.

[0049] In the description of the embodiments of this disclosure, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0050] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0052] In the description of the embodiments of this disclosure, the technical terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "circumferential," "height direction," "first direction," and "second direction," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated, or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0053] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" 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 or an electrical connection; 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0054] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0055] With the development of clean energy, more and more devices are using electricity as their driving force, leading to the rapid development of power batteries, such as lithium-ion batteries, which can store a large amount of electrical energy and can be repeatedly charged and discharged. These power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields.

[0056] The battery mentioned in the embodiments of this disclosure refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this disclosure may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0057] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated one, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated one, serving as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, etc. To ensure that a large current can pass through without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together. The separator can be made of PP (polypropylene) or PE (polyethylene), etc.

[0058] For example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0059] For example, the positive electrode current collector can be a metal foil or a composite current collector. For instance, the metal foil can be silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium. The composite current collector may include a polymer substrate and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0060] For example, the negative electrode can be a negative electrode sheet, which may include a negative electrode current collector.

[0061] For example, the negative electrode current collector can be a metal foil or a composite current collector. For instance, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc.

[0062] For example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0063] Exemplarily, the negative electrode active material may be any negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, this disclosure is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0064] The battery cell also includes an insulating film and a casing. The insulating film covers the outside of the electrode assembly, and the casing encapsulates the electrode assembly covered with the insulating film to form the battery cell. The insulating film can be Mylar film, and the casing can be an aluminum casing or a steel casing. After the electrode assembly is wound and formed, the Mylar film and casing are encapsulated through a Mylar film wrapping process and a casing insertion process. The Mylar film serves to seal and protect the electrode assembly, and it effectively insulates the electrode assembly and casing from each other, preventing internal short circuits within the battery cell. The casing provides protection.

[0065] Exemplarily, the housing includes a top cover and a casing, the casing having an opening, and the top cover closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The casing may have one or more openings. The top cover may also have one or more openings.

[0066] For example, the housing is provided with at least one electrode terminal, which is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal can be located on the top cover or on the housing.

[0067] For example, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cell.

[0068] For example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. There are no particular limitations in the embodiments disclosed herein.

[0069] For example, the battery cell also includes a pressure relief structure, which can be provided on the top cover or the outer casing, to release the internal pressure or temperature of the battery cell.

[0070] The development of battery technology must take into account multiple design factors, such as energy density, discharge capacity, charge-discharge rate and other performance parameters. In addition, battery reliability also needs to be considered.

[0071] A battery cell includes a casing, a top cover, an insulator, an electrode assembly, and an insulating film. The top cover seals the opening of the casing. The electrode assembly is disposed within the casing, and the insulator is disposed between the top cover and the electrode assembly. The insulator abuts against the electrode assembly to position it. The insulating film covers at least a portion of the electrode assembly and the insulator to insulate the electrode assembly from the casing. In related technologies, after a battery cell is charged and discharged, the electrode assembly expands in the thickness direction, making it easy for the large surface (first surface) of the electrode assembly to come into contact with the casing, while the sides (other surfaces besides the first surface) of the electrode assembly are less likely to come into contact with the casing. Therefore, when thermal runaway occurs inside the electrode assembly, the internal temperature of the electrode assembly rises sharply, and the large surface of the electrode assembly easily melts the insulating film, allowing heat to be transferred to the large surface of the casing, and then to adjacent battery cells, causing thermal diffusion between adjacent battery cells, resulting in fire and explosion.

[0072] Therefore, to improve the reliability of a single battery cell, this disclosure provides a single battery cell including an electrode assembly, a housing, and an insulating film. The electrode assembly includes multiple surfaces, including a first surface, which is the surface with the largest area among the multiple surfaces. The housing forms a receiving space for accommodating the electrode assembly. The insulating film covers the outer periphery of the electrode assembly and is located between the electrode assembly and the housing. The insulating film has a first thickness region and a second thickness region, where the thickness of the first thickness region is greater than the thickness of the second thickness region. The first thickness region is located in the region where the first surface of the electrode assembly is located.

[0073] The battery cell provided in this disclosure includes an electrode assembly, a housing, and an insulating film. The insulating film has a first thickness region and a second thickness region, where the first thickness region is thicker than the second thickness region. The first thickness region is located on the first surface of the electrode assembly. In other words, the thickness of the insulating film covering at least a portion of the first surface of the electrode assembly is greater than the thickness of the insulating film covering the other surfaces of the electrode assembly. Thus, when the electrode assembly experiences a short circuit, overcharge, or internal thermal runaway, the rapid heat transfer to the housing can be improved, enhancing the thermal insulation effect of the insulating film and thereby improving the reliability of the battery cell.

[0074] The technical solutions described in the embodiments of this disclosure are applicable to batteries and electrical devices that use batteries.

[0075] The battery mentioned in the embodiments of this disclosure refers to a single physical module comprising at least one battery cell provided in the embodiments of this disclosure. One or more battery cells provide higher voltage and capacity. For example, the battery mentioned in this disclosure may include a battery module or battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0076] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This disclosure does not impose any special limitations on the above-mentioned electrical devices.

[0077] It should be noted that the technical solutions described in this disclosure are not limited to the batteries and electrical devices described above, but can also be applied to all batteries including housings and electrical devices using batteries. However, for the sake of brevity, the following embodiments are all described using electric vehicles as examples.

[0078] Referring to Figure 1, a controller 200, a motor 300, and a battery 100 can be installed inside the vehicle 100. The controller 200 controls the battery 100 to supply power to the motor 300. For example, the battery 100 can be installed at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, it can serve as the operating power source for the vehicle 1000's electrical system, such as for the power requirements of starting, navigation, and operation. In another embodiment of this disclosure, the battery 100 can not only serve as the operating power source for the vehicle 1000 but also as the driving power source, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0079] To meet different power demands, battery 100 may include multiple battery cells 10, where each battery cell 10 is the smallest unit that makes up a battery module or battery pack. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid configuration, where some cells are connected in series and others in parallel. Multiple battery cells 10 can be directly connected in series, parallel, or in a hybrid configuration and then housed within battery box 20. Alternatively, battery 100 can consist of multiple battery cells 10 first connected in series, parallel, or in a hybrid configuration to form battery modules, which are then connected in series, parallel, or in a hybrid configuration to form a whole and housed within battery box 20. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between multiple battery cells 10. Each battery cell 10 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. Battery cells 10 can be cylindrical, flat, cuboid, or other shapes.

[0080] Referring to Figure 2, the battery 100 includes a battery case 20 and at least one battery cell 10, with the battery cell 10 disposed within the mounting space of the battery case 20.

[0081] The battery box 20 can be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or it can be a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders, or spheres. The battery box 20 can be made of alloy materials such as aluminum alloy or iron alloy, polymer materials such as polycarbonate or polyisocyanurate foam, or composite materials such as glass fiber and epoxy resin.

[0082] The battery box 20 is used to accommodate the battery cell 10, and the battery box 20 can have various structures. In some embodiments, the battery box 20 may include a first box portion 21 and a second box portion 22, which overlap each other, and together define an installation space for accommodating the battery cell 10. The second box portion 22 may be a hollow structure with one end open, and the first box portion 21 may be a plate-like structure, with the first box portion 21 covering the open side of the second box portion 22 to form a battery box 20 with an installation space; alternatively, both the first box portion 21 and the second box portion 22 may be hollow structures with one side open, with the open side of the first box portion 21 covering the open side of the second box portion 22 to form a battery box 20 with an installation space. Of course, the first box portion 21 and the second box portion 22 can have various shapes, such as cylinders, cuboids, etc.

[0083] To improve the sealing performance after the first housing part 21 and the second housing part 22 are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 21 and the second housing part 22.

[0084] Assuming that the first box section 21 covers the top of the second box section 22, the first box section 21 can also be called the upper box cover, and the second box section 22 can also be called the lower box cover.

[0085] This disclosure provides a battery cell 10, as shown in Figures 3 to 6. The battery cell 10 includes an electrode assembly 2, a housing, and an insulating film 1. The electrode assembly 2 includes multiple surfaces, including a first surface, which is the surface with the largest area among the multiple surfaces. The housing forms a receiving space to accommodate the electrode assembly 2. The insulating film 1 covers the outer periphery of the electrode assembly 2 and is located between the electrode assembly 2 and the housing 3. The insulating film 1 has a first thickness region and a second thickness region. The thickness of the first thickness region is greater than the thickness of the second thickness region. The first thickness region is located in the region where the first surface of the electrode assembly 2 is located.

[0086] For example, the battery cell 10 includes a housing 3, an insulating film 1 covering the outside of the electrode assembly 2, and the housing 3 encapsulates the electrode assembly 2 covered with the insulating film 1 to form the battery cell 10.

[0087] It should be noted that the first surface in this embodiment is the large surface of the electrode assembly 2, which is the surface with the largest area among the multiple surfaces of the electrode assembly 2.

[0088] Taking a square battery cell 10 as an example, in a vertical state, the surface formed by the length and width directions of the battery cell 10 is the bottom surface of the battery cell 10, the surface formed by the length and height directions of the battery cell 10 is the large surface of the battery cell 10, and the surface formed by the width and height directions of the battery cell 10 is the side surface of the battery cell 10.

[0089] Here, electrode assembly 2 is formed by winding together a positive electrode plate, a negative electrode plate, and a separator. The separator is used to isolate the positive electrode plate and the negative electrode plate, and provides insulation between them.

[0090] The insulating film 1 is, for example, a Mylar film. The Mylar film covers the outer periphery of the electrode assembly 2 and is located between the electrode assembly 2 and the housing. It serves to seal and protect the electrode assembly 2, and the Mylar film can effectively insulate the electrode assembly 2 and the housing 3 from each other, preventing short circuits inside the battery cell 10. The housing 3 protects the internal electrode assembly 2.

[0091] It is understandable that the insulating film 1 can also be regarded as a heat insulation layer between the electrode assembly 2 and the outer shell 3, that is, it plays a heat insulation role for the electrode assembly 2.

[0092] The insulating film 1 has a first thickness region and a second thickness region. The thickness of the first thickness region is greater than the thickness of the second thickness region. In other words, the insulating film 1 has at least two regions with different thicknesses, so the insulating film 1 can be arranged according to requirements.

[0093] The first thickness region is located in the region where the first surface of the electrode assembly 2 is located. That is, the thickness of the insulating film 1 covering at least a portion of the first surface of the electrode assembly 2 is greater than the thickness of the insulating film 1 covering the small portion of the electrode assembly 2.

[0094] In related technologies, after a battery cell is charged and discharged, the electrode assembly expands in the thickness direction, making it easy for the large surface of the electrode assembly to come into contact with the outer casing, while the sides of the electrode assembly are less likely to come into contact with the outer casing. Therefore, when thermal runaway occurs inside the electrode assembly, the internal temperature rises sharply, and the insulating film on the large surface of the electrode assembly easily melts, allowing heat to be transferred to the large surface of the outer casing, and then to adjacent battery cells, causing thermal diffusion between adjacent battery cells, leading to fire and explosion.

[0095] The battery cell 10 provided in this embodiment includes an electrode assembly 2, a housing, and an insulating film 1. The insulating film 1 has a first thickness region and a second thickness region, with the thickness of the first thickness region being greater than the thickness of the second thickness region. By setting the first thickness region in the area where the first surface of the electrode assembly 2 is located, that is, the thickness of the insulating film 1 covering at least a portion of the first surface of the electrode assembly 2 is greater than the thickness of the insulating film 1 covering the other surfaces of the electrode assembly 2 excluding the first surface, the rapid heat transfer to the housing 3 can be improved when the electrode assembly 2 experiences a short circuit, overcharge, or internal thermal runaway, thereby improving the heat insulation and protection effect of the insulating film 1 and thus improving the reliability of the battery cell 10.

[0096] In related technologies, the insulating film of the electrode assembly is always covered by side overlap. That is, the insulating film on the large surface of the electrode assembly is one layer, which is equivalent to the heat insulation layer on the large surface of the electrode assembly being one layer of insulating film, and the insulating film on at least a part of the side surface of the electrode assembly is two layers, which is equivalent to the heat insulation layer on at least a part of the side surface of the electrode assembly being two layers of insulating film.

[0097] In some embodiments, referring to Figures 4 to 6, the insulating film 1 is formed by folding a substrate 11. The insulating film 1 includes an overlapping region where the substrates 11 overlap. The overlapping region constitutes a first thickness region.

[0098] In other words, the substrate 11 is formed into an insulating film 1 of the required shape through steps such as folding and bonding. The substrate 11 is wound around the circumference of the electrode assembly. During the winding process, the tail of the substrate 11 extends beyond the head of the substrate 11, so that the substrate 11 forms an overlapping area between the head and the tail. The thickness of the overlapping area is twice the thickness of the substrate.

[0099] The insulating film 1 includes an overlapping area where substrates 11 are overlapped, meaning that the number of substrates 11 layers in the overlapping area of ​​the insulating film 1 is at least two.

[0100] Here, the substrates 11 have the same thickness, but the thickness of the insulating film 1 in the overlapping area is increased by overlapping the substrates 11.

[0101] In this embodiment, the insulating film 1 includes an overlapping area of ​​the substrate 11, and the overlapping area constitutes a first thickness area. That is, the insulating film 1 in the area where the first surface of the electrode assembly 2 is located has at least two layers, which means that the heat insulation layer in the area where the first surface of the electrode assembly 2 is located has at least two layers of insulating film 1. Thus, the thickness of the insulating film 1 in the area where the first surface of the electrode assembly 2 is located is greater than the thickness of the insulating film 1 on other surfaces, thereby increasing the thickness of the insulating film 1 between the first surface of the electrode assembly 2 and the outer shell 3, and thus improving the heat insulation effect of the insulating film 1.

[0102] In some embodiments, the insulating film 1 includes a substrate 11 and a sprayed coating layer, wherein a portion of the substrate 11 is provided with the sprayed coating layer to form a first thickness region.

[0103] Here, by spraying an insulating coating such as ceramic onto the substrate 11 corresponding to the first surface of the electrode assembly 2, the thickness of the insulating film 1 corresponding to the first surface of the electrode assembly 2 is increased, thereby improving the heat insulation effect of the insulating film 1.

[0104] In some embodiments, the insulating film 1 includes a substrate 11 and a coding adhesive, wherein a portion of the substrate 11 is provided with the coding adhesive to form a first thickness region.

[0105] Here, by setting a coding adhesive on the substrate 11 corresponding to the first surface of the electrode assembly 2, the thickness of the insulating film 1 corresponding to the first surface of the electrode assembly 2 is increased, thereby improving the heat insulation effect of the insulating film 1.

[0106] In some embodiments, the number of electrode components 2 is one, and both first surfaces of the electrode component 2 are provided with a first thickness region.

[0107] In this embodiment, both first surfaces of the electrode assembly 2 are provided with a first thickness region. That is, the thickness of the insulating film 1 covering at least a portion of the two first surfaces of the electrode assembly 2 is greater than the thickness of the insulating film 1 covering the other surfaces of the electrode assembly 2 other than the first surfaces. This further improves the heat insulation and protection effect of the insulating film 1 and further improves the reliability of the battery cell 10.

[0108] Of course, in other embodiments, one of the first surfaces of the electrode assembly 2 may be provided with a first thickness region, and the other first surface may be provided with a first thickness region.

[0109] In some embodiments, the battery cell 10 includes a housing 3, an electrode assembly 2 is disposed inside the housing 3, and there are two electrode assemblies 2. The regions where the first surfaces of the two electrode assemblies 2 are opposite each other are provided with a first thickness region, and the regions where the first surfaces of the two electrode assemblies 2 are opposite each other are not provided with a first thickness region.

[0110] Here, the large surfaces of the two electrode components 2 facing away from each other are provided with a first thickness area. The fact that the large surfaces of the two electrode components 2 facing each other are not provided with a first thickness area means that the large surfaces of the two electrode components 2 near the outer shell 3 are provided with a first thickness area, while the large surfaces near the other electrode component 2 are not provided with a first thickness area.

[0111] In this way, while improving the heat insulation and protection effect of the insulating film 1, the space occupied by the insulating film 1 can also be reduced, which is beneficial to improving the performance of the battery.

[0112] It should be noted that the above methods can be implemented individually or simultaneously.

[0113] In some embodiments, referring to FIG5, the length of the electrode assembly 2 is L0, and the dimension of the first thickness region along the length direction of the electrode assembly 2 is L1, wherein the ratio of L1 to L0 is in the range of 0.8-1. For example, it is 0.8, 0.85, 0.9, 0.95, or 1, etc.

[0114] By setting the ratio of the dimension of the first thickness region along the length of the electrode assembly 2 to the length of the electrode assembly 2 to 0.8-1, the insulating film 1 corresponding to the first surface of the electrode assembly 2 can have sufficient structural strength and heat insulation effect, while not affecting the assembly of the battery cell 10, and maintaining the structural compactness and performance of the battery cell 10.

[0115] In some embodiments, as shown in Figures 4 to 6, the insulating film 1 is formed by folding a substrate 11, the substrate 11 having a thickness of 0.05 mm to 0.3 mm.

[0116] For example, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.1mm, 0.12mm, 0.13mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.23mm, 0.25mm, 0.27mm, 0.29mm, or 0.3mm, etc.

[0117] By setting the thickness of the substrate 11 to 0.05mm-0.3mm, and ensuring that the thickness of the insulating film 1 covering at least a portion of the first surface of the electrode assembly 2 is greater than the thickness of the insulating film 1 covering the other surfaces of the electrode assembly 2, the following advantages can be achieved: First, the thickness of the insulating film 1 corresponding to the first surface of the electrode assembly 2 can be increased, thereby providing better heat insulation protection. Second, given the same thickness of the insulating film 1 corresponding to the first surface of the electrode assembly 2, the thickness of the insulating film 1 corresponding to the other surfaces of the electrode assembly 2 can be reduced, thereby achieving a decrease in the cost of the battery 100.

[0118] In some embodiments, the insulating film 1 is formed by folding a substrate 11, the substrate 11 having a first wall thickness region and a second wall thickness region, the thickness of the first wall thickness region being greater than the thickness of the second wall thickness region, wherein the first wall thickness region is folded to form a first thickness region, and the second wall thickness region is folded to form a second thickness region.

[0119] The substrate 11 has a first wall thickness region and a second wall thickness region. The thickness of the first wall thickness region is greater than the thickness of the second wall thickness region. In other words, the substrate 11 has at least two regions with different thicknesses, so the substrate 11 can be arranged according to requirements.

[0120] The thickness of the first wall thickness region is greater than the thickness of the second wall thickness region. The first wall thickness region is folded to form the first thickness region, and the second wall thickness region is folded to form the second thickness region. In other words, the thickness of the insulating film 1 covering at least a portion of the first surface of the electrode assembly 2 is greater than the thickness of the insulating film 1 covering the other surfaces of the electrode assembly 2, excluding the first surface.

[0121] In this embodiment, the substrate 11 is configured with two different wall thicknesses, including a first wall thickness region and a second wall thickness region. The first wall thickness region, with a larger wall thickness, is disposed on the first surface of the electrode assembly 2, while the second wall thickness region, with a smaller wall thickness, is disposed on other surfaces of the electrode assembly 2 besides the first surface. This effectively increases the thickness of the insulating film 1 corresponding to the first surface of the electrode assembly 2 compared to the insulating film 1 on other surfaces, thereby increasing the thickness of the insulating film 1 between the first surface of the electrode assembly 2 and the outer shell 3, and thus improving the heat insulation effect of the insulating film 1.

[0122] In some embodiments, the battery cell 10 includes a housing 3, and an electrode assembly 2 covered with an insulating film 1 is disposed inside the housing 3. The distance between the top of the insulating film 1 and the top cover 32 of the housing 3 is 0.1mm-5mm. For example, it is 0.1mm, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.8mm, 3mm, 3.5mm, 3.8mm, 4mm, 4.5mm, 4.8mm, or 5mm, etc.

[0123] For example, the housing 3 includes a top cover 32 and a housing 31, the housing 31 having an opening, and the top cover 32 closing the opening to form a sealed space for accommodating the electrode assembly 2 and substances such as electrolytes.

[0124] Here, the distance between the top of the insulating film 1 and the top cover 32 of the outer casing 3 refers to the distance between the insulating film 1 and the top cover 32 in the height direction of the battery cell 10.

[0125] Exemplarily, the battery cell 10 also includes a lower plastic layer, a top cover 32 that closes the opening of the housing 31, an electrode assembly 2 disposed within the housing 3, and the lower plastic layer disposed between the top cover 32 and the electrode assembly 2. The lower plastic layer abuts against the electrode assembly 2 to position the electrode assembly 2. An insulating film 1 covers at least a portion of the electrode assembly 2 and the lower plastic layer to insulate and isolate the electrode assembly 2 from the housing 31.

[0126] Here, the insulating film 1 is connected to the lower plastic by ultrasonic welding or hot melting.

[0127] In this embodiment, by setting the distance between the top of the insulating film 1 and the top cover 32 of the housing 3 to 0.1mm-5mm, it is beneficial to achieve the connection between the insulating film 1 and the top cover 32 while minimizing the impact on assembling the top cover 32 into the housing 31.

[0128] In some embodiments, referring to Figures 4 to 6, this disclosure also provides an insulating film 1, which serves as a battery cell 10 in any embodiment of this disclosure, and is used to cover the electrode assembly 2 of the battery cell 10.

[0129] The insulating film 1 has a first thickness region and a second thickness region, with the first thickness region being thicker than the second thickness region. The first thickness region is located on the first surface of the electrode assembly 2. This means that the thickness of the insulating film 1 covering at least a portion of the first surface of the electrode assembly 2 is greater than the thickness of the insulating film 1 covering the other surfaces of the electrode assembly 2. Therefore, when the electrode assembly 2 experiences a short circuit, overcharge, or internal thermal runaway, the rapid heat transfer to the outer casing 3 can be mitigated, improving the heat insulation and protection effect of the insulating film 1, and ultimately enhancing the reliability of the battery cell 10.

[0130] In some embodiments, please continue to refer to Figures 4 to 6. The insulating film 1 is formed by folding a substrate 11 having a bottom covering wall 113, a first side covering wall 112 and a second side covering wall 111. The area of ​​the second side covering wall 111 is larger than the area of ​​the first side covering wall 112. When the substrate 11 is in the unfolded state, the bottom covering wall 113 is connected to a first side covering wall 112 at both ends along the first direction, and each first side covering wall 112 is connected to a second side covering wall 111 at both ends along the second direction. The first direction intersects the second direction.

[0131] The first direction intersects with the second direction, meaning that the first direction and the second direction are not parallel. For example, the first direction and the second direction are perpendicular to each other.

[0132] Here, the first direction is the length direction of the battery cell 10, and the second direction is the width direction of the battery cell 10.

[0133] Two first side covering walls 112 are respectively connected to the two ends of the bottom covering wall 113 along the first direction, and each first side covering wall 112 is respectively connected to a second side covering wall 111 at both ends along the second direction. That is, when the substrate 11 is in the unfolded state, the substrate 11 includes four second side covering walls 111. When the substrate 11 is in the covered state, two second side covering walls 111 together cover the large surface of the electrode assembly 2, and the two second side covering walls 111 have an overlapping area, which constitutes the first thickness area. The non-overlapping area of ​​the second side covering walls 111 constitutes the second thickness area. The bottom covering wall 113 covers the bottom surface of the electrode assembly 2, and the two first side covering walls 112 cover the two sides of the electrode assembly 2 respectively.

[0134] The structural strength of the connection between the bottom covering wall 113, the first side covering wall 112, and the second side covering wall 111 is less than that of the bottom covering wall 113, the first side covering wall 112, and the second side covering wall 111. For example, by setting indentations or forming a structurally weakened area, it is beneficial to fold at the connection, thereby improving assembly efficiency and reliability.

[0135] In this embodiment, with the substrate 11 in a covered state, each first surface of the electrode assembly 2 is covered with two second side covering walls 111, and the two second side covering walls 111 have an overlapping area, which constitutes a first thickness area. That is, by setting the insulating film 1 to overlap on the large surface of the electrode assembly 2, the thickness of the insulating film 1 between the first surface of the electrode assembly 2 and the outer shell 3 is increased, thereby improving the heat insulation effect of the insulating film 1.

[0136] It should be noted that the length L0 of the electrode assembly 2, the dimension L1 of the first thickness region along the length direction of the electrode assembly 2, the thickness of the substrate 11, and the distance between the top of the insulating film 1 and the top cover 32 of the outer shell 3 can be obtained by testing with a high-precision thickness gauge and vernier calipers under normal temperature conditions.

[0137] The electrode terminals on the housing 3 are electrically connected to the tabs of the electrode assembly 2. For example, referring to FIG4, the battery cell 10 is provided with an adapter 6, through which the electrode terminals are indirectly connected to the tabs.

[0138] For example, referring to Figure 4, the battery cell 10 includes a bottom support plate 5, which is disposed inside the housing 3 and located at the bottom of the electrode assembly 2.

[0139] For example, referring to FIG4, the battery cell 10 includes a blue film 4, which covers the outer periphery of the housing 3 to insulate adjacent battery cells 10.

[0140] In the description of this disclosure, references to terms such as "in one embodiment," "in some embodiments," "in other embodiments," "in yet another embodiment," or "exemplary," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the embodiments of this disclosure. In this disclosure, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine the different embodiments or examples described in this disclosure, as well as the features of the different embodiments or examples, without contradiction.

[0141] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure are included within the scope of protection of this disclosure.

Claims

1. A single battery cell, comprising: An electrode assembly, the electrode assembly comprising a plurality of surfaces, the plurality of surfaces including a first surface, the first surface being the surface with the largest area among the plurality of surfaces; The housing forms a receiving space to accommodate the electrode assembly; An insulating film is provided, which covers the outer periphery of the electrode assembly and is located between the electrode assembly and the housing. The insulating film has a first thickness region and a second thickness region, wherein the thickness of the first thickness region is greater than the thickness of the second thickness region, and the first thickness region is located in the region where the first surface of the electrode assembly is located.

2. The battery cell according to claim 1, wherein, The insulating film is formed by folding a substrate, and the insulating film includes an overlapping region formed by overlapping the substrate, the overlapping region constituting the first thickness region.

3. The battery cell according to any one of claims 1-2, wherein, The length of the electrode assembly is L0, and the dimension of the first thickness region along the length direction of the electrode assembly is L1, wherein the ratio of L1 to L0 is in the range of 0.8-1.

4. The battery cell according to any one of claims 1-3, wherein, The insulating film is formed by folding a substrate, the thickness of which is 0.05mm-0.3mm.

5. The battery cell according to any one of claims 1-4, wherein, The insulating film is formed by folding a substrate, the substrate having a first wall thickness region and a second wall thickness region, the thickness of the first wall thickness region being greater than the thickness of the second wall thickness region, wherein the first wall thickness region is folded to form the first thickness region, and the second wall thickness region is folded to form the second thickness region.

6. The battery cell according to any one of claims 1-5, wherein, The battery cell includes a housing, and the electrode assembly covered with the insulating film is disposed inside the housing. The distance between the top of the insulating film and the top cover of the housing is 0.1mm-5mm.

7. The battery cell according to any one of claims 1-6, wherein, The number of electrode components is one, and the first thickness region is provided in both regions of the first surface of the electrode component.

8. The battery cell according to any one of claims 1-6, wherein, The battery cell includes a housing, and the electrode assembly is disposed inside the housing. There are two electrode assemblies. The first thickness region is provided in the area where the first surfaces of the two electrode assemblies are opposite to each other, and the first thickness region is not provided in the area where the first surfaces of the two electrode assemblies are opposite to each other.

9. The battery cell according to claim 1, wherein, The insulating film includes a substrate and a sprayed coating layer, wherein a portion of the substrate is provided with the sprayed coating layer to form the first thickness region.

10. The battery cell according to claim 1, wherein, The insulating film includes a substrate and a coding adhesive, wherein a portion of the substrate is provided with the coding adhesive to form the first thickness region.

11. An insulating film used as a battery cell according to any one of claims 1-6, the insulating film being used to cover an electrode assembly of the battery cell.

12. The insulating film according to claim 11, wherein, The insulating film is formed by folding a substrate having a bottom covering wall, a first side covering wall, and a second side covering wall, wherein the area of ​​the second side covering wall is larger than the area of ​​the first side covering wall; and when the substrate is in an unfolded state, the bottom covering wall is connected to a first side covering wall at both ends along a first direction, and each first side covering wall is connected to a second side covering wall at both ends along a second direction, wherein the first direction intersects the second direction.

13. A battery comprising at least one battery cell as described in any one of claims 1-12.

14. An electrical device comprising the battery of claim 13, the battery being used to provide electrical energy.

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