Battery monomer, battery device and electric device

Abstract

The utility model relates to a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, an electrode assembly, an end cover assembly and an insulating film, the housing has an opening. The electrode assembly is arranged in the shell and comprises an electrode main body and a tab; the end cover assembly comprises an end cover and an insulating part, the end cover covers the opening, and the insulating part is arranged on the side, facing the electrode assembly, of the end cover. The insulating film is arranged in the shell, at least part of the insulating film is located between the insulating component and the electrode main body, the melting point of the insulating film is higher than that of the insulating component, and the insulating film is provided with a weak part which is arranged between the electrode main body and the insulating component. According to the battery monomer provided by the invention, the insulating film is provided with the weak part, and gas can burst through the weak part of the insulating film to reach the end cover assembly under the condition of thermal runaway, so that the risk of shell breakage caused by expansion of the electrode assembly is reduced.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to battery cells, battery devices, and electrical devices. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and rechargeable alkaline zinc-manganese batteries, among others.

[0003] In the development of batteries, how to ensure the reliability of individual battery cells is a technical problem that urgently needs to be solved. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device, which aim to improve the reliability of the battery cell to a certain extent.

[0005] In a first aspect, this application proposes a battery cell, which includes a housing, an electrode assembly, an end cap assembly, and an insulating film. The housing has an opening. The electrode assembly is disposed within the housing and includes an electrode body and a tab. The end cap assembly includes an end cap and an insulating component, the end cap closing onto the opening, and the insulating component being disposed on the side of the end cap facing the electrode assembly. The insulating film is disposed within the housing, at least a portion of which is located between the insulating component and the electrode body. The melting point of the insulating film is higher than the melting point of the insulating component, and the insulating film has a weak portion located between the electrode body and the insulating component.

[0006] The battery cell provided in this application has an insulating film, at least partially disposed between the electrode body and the insulating components. This insulating film effectively restrains the electrode assembly, suppressing its contraction under heat, reducing short-circuit points, decreasing the likelihood of thermal runaway caused by short circuits, and improving the reliability of the battery cell. Furthermore, the insulating film has a higher melting point than the insulating components. In the event of thermal runaway, this reduces the risk of high-temperature gas directly impacting the insulating components, causing them to melt and deform, damaging the electrode assembly and leading to a short circuit. In addition, the insulating film has weak points. In the event of thermal runaway, gas can breach these weak points to reach the end cap assembly. Therefore, the insulating film does not obstruct gas transmission, reducing the risk of casing rupture due to electrode assembly expansion, and also reducing the risk of explosion caused by short circuits, further improving the reliability of the battery cell.

[0007] According to one embodiment of this application, the insulating component includes a main body and a protrusion. The main body is fitted to an end cap. The protrusion protrudes from the surface of the main body away from the end cap, and at least a portion of the insulating film is disposed between the protrusion and the electrode body in the arrangement direction of the electrode assembly and the end cap assembly.

[0008] In these alternative embodiments, at least a portion of the insulating film is disposed between the protrusion and the electrode body to prevent the protrusion from compressing the electrode assembly after thermal deformation, thereby reducing the risk of short circuits caused by electrode assembly breakage.

[0009] According to one embodiment of this application, the protrusion is pressed against the electrode body by an insulating film.

[0010] In these alternative embodiments, when the protrusion presses against the electrode assembly through the insulating film, the insulating film acts as an isolation layer. The insulating film can also buffer the pressure applied by the protrusion, so that the pressure is evenly distributed on the surface of the electrode body, reducing the damage to the electrode assembly caused by excessive local pressure, and also reducing the occurrence of insulating film detachment.

[0011] According to one embodiment of this application, the insulating component includes a plurality of protrusions, including two first protrusions and a second protrusion. The two first protrusions are disposed at opposite ends of the main body, and the second protrusion is located between the two first protrusions. The battery cell includes a plurality of insulating films, which overlap with the first and second protrusions respectively in the arrangement direction of the electrode assembly and the end cap assembly.

[0012] In these alternative embodiments, multiple insulating films overlap with the first and second protrusions respectively, forming multiple insulation protection systems. This distribution method can more broadly cover areas where short circuit risks may occur.

[0013] According to one embodiment of this application, the battery cell further includes a pressure relief mechanism disposed on the end cap and located on the side of the second protrusion opposite to the electrode body.

[0014] According to one embodiment of this application, at least a portion of the insulating film is attached to at least one of the electrode body and the insulating component.

[0015] In these alternative embodiments, by attaching the insulating film to the electrode body, the insulating film can not only increase the thickness of the area and enhance the adhesion between the insulator and the electrode, but also hold the insulator located at the outermost ring of the electrode assembly, suppressing its shrinkage behavior when heated and reducing short circuit points.

[0016] According to one embodiment of this application, the electrode body has an end face facing the end cap assembly, and an electrode tab extends from the end face. An insulating film is attached to the end face of the electrode body.

[0017] In these alternative embodiments, this configuration allows for a larger contact area between the insulating film and the end face of the electrode body, increasing the connection stability between the insulating film and the electrode body. Furthermore, the attachment of the insulating film to the end face can help improve the sealing performance of the battery cell, reducing electrolyte leakage within the battery cell to some extent.

[0018] According to one embodiment of this application, the electrode body further includes an outer peripheral surface disposed around the end face, the outer peripheral surface being connected to the end face. An insulating film is also attached to the outer peripheral surface.

[0019] In these alternative embodiments, the insulating film is attached to the outer peripheral surface, reducing the likelihood of the outer peripheral surface forming a conductive path with surrounding components, thereby reducing the risk of short circuits.

[0020] According to one embodiment of this application, the outer peripheral surface includes two first surfaces disposed opposite to each other along a first direction and two second surfaces disposed opposite to each other along a second direction. The second surfaces are connected to the two adjacent first surfaces. The second surfaces are at least partially arc-shaped, and the second direction is perpendicular to the first direction. At least a portion of the insulating film is attached to the second surfaces.

[0021] In these optional embodiments, the insulating film is attached to a second surface disposed along the second direction on the outer peripheral surface, reducing the volume occupied by the insulating film, making the structure of the insulating film compact and the overall space occupied smaller, improving the overall layout compactness of the battery cell and increasing the energy density of the battery cell.

[0022] According to one embodiment of this application, the insulating film is also attached to the first surface.

[0023] According to one embodiment of this application, the electrode body includes a first electrode body, and the electrode tab includes a first electrode tab. The first electrode body includes a base portion and a thinned portion, the thinned portion being connected between the base portion and the first electrode tab, and at least a portion of the thickness of the thinned portion is less than the thickness of the base portion. In the thickness direction of the first electrode, the portion of the insulating film attached to the outer peripheral surface at least partially overlaps with the thinned portion.

[0024] In these alternative embodiments, due to the presence of the thinned portion and the uneven distribution of expansion and contraction forces during long-term use of the electrode assembly, there is a defect in the poor adhesion between the insulating member and the first electrode. Therefore, by attaching an insulating film to the outer surface of the electrode body and at least partially overlapping the thinned portion, not only can the rate at which external heat sources transfer heat to this area be slowed down, but the contraction of the insulating member can also be suppressed, further reducing the risk of short circuits due to lack of insulation protection of the electrode.

[0025] According to one embodiment of this application, the insulating film has a recess, and the portion of the insulating film corresponding to the bottom surface of the recess forms a weak portion.

[0026] In these alternative embodiments, the thinner weak points are preferentially fractured when subjected to thermal shock, allowing high-temperature gases to pass through the insulating film and reducing the risk of housing rupture caused by electrode assembly expansion.

[0027] According to one embodiment of this application, the thickness m of the weak portion and the maximum thickness d of the insulating film satisfy the following condition: 60% ≤ m / d ≤ 90%.

[0028] In these alternative embodiments, the weak point has a suitable thickness that allows it to be blasted open by gas in the event of thermal runaway, while also providing a certain degree of thermal insulation to protect the integrity of the insulating component structure.

[0029] According to one embodiment of this application, the insulating film includes a body portion and a pressure relief portion, a weak portion is disposed along the outer periphery of the pressure relief portion, and the weak portion is connected to the body portion and the pressure relief portion.

[0030] In these alternative embodiments, when thermal runaway occurs, the pressure relief section can, with the help of the weak part, separate from the main body first along the weak part after the gas reaches a certain pressure threshold, thereby providing a release channel for the internal high-pressure gas, etc., and reducing the possibility of shell rupture or even more serious damage caused by excessive pressure.

[0031] According to one embodiment of this application, the projection of the weak portion in the direction perpendicular to the thickness of the insulating film is at least partially arc-shaped.

[0032] In these alternative embodiments, this arrangement facilitates the manufacturing of the weak points.

[0033] According to one embodiment of this application, the electrode assembly includes a first electrode, a second electrode, and a spacer. The first and second electrodes have opposite polarities, and the spacer is used to isolate the first and second electrodes. The first electrode, the second electrode, and the spacer are wound along a winding direction to form the electrode assembly. The protruding direction of the arc-shaped weak portion is consistent with the winding direction of the portion of the electrode assembly overlapping the weak portion.

[0034] In these alternative embodiments, the arcuate weak portion protrudes in the same direction as the winding direction of the electrode assembly overlapping the weak portion, reducing the risk of the pressure relief portion and the weak portion being squeezed out of the electrode assembly, and improving the effectiveness of thermal insulation and insulation of the insulating components.

[0035] Secondly, this application provides a battery device including the aforementioned battery cell.

[0036] Thirdly, this application provides an electrical device, including a battery cell or a battery device as described above, wherein the battery cell or battery device is used to store or provide electrical energy.

[0037] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0038] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0040] Figure 2 This is an exploded view of a battery device provided in an embodiment of this application;

[0041] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application;

[0042] Figure 4 This is a schematic diagram of the structure of a battery cell provided in an embodiment of this application;

[0043] Figure 5 for Figure 4 The diagram shown is an enlarged structural schematic of a battery cell at point b, provided in an embodiment of this application.

[0044] Figure 6 This is a schematic diagram of the end cap assembly and insulating film of a battery cell provided in an embodiment of this application;

[0045] Figure 7 This is a schematic diagram of the electrode assembly and insulating film of a battery cell provided in an embodiment of this application;

[0046] Figure 8 This is a partial structural schematic diagram of the electrode assembly and insulating film of a battery cell provided in an embodiment of this application;

[0047] Figure 9 This is a schematic diagram of the structure of the insulating film of a battery cell provided in an embodiment of this application;

[0048] Figure 10 This is a schematic diagram of the structure of the insulating film of a battery cell provided in another embodiment of this application;

[0049] Figure 11 This is a schematic diagram of the electrode assembly and insulating film of a battery cell provided in another embodiment of this application.

[0050] The accompanying drawings may not be drawn to scale.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1000, vehicles;

[0053] 100. Battery assembly; 200. Controller; 300. Motor;

[0054] 1a. Battery module; 1b. First housing; 1c. Second housing;

[0055] 10. Battery cells;

[0056] 1. Shell;

[0057] 2. Electrode assembly; 21. Electrode body; 211. End face; 212. Outer peripheral surface; 2121. First surface; 2122. Second surface; 213. First electrode body; 2131. Substrate; 2132. Thinned portion; 22. Electrode tab; 221. First electrode tab; 2a. First electrode; 2b. Second electrode; 2c. Spacer;

[0058] 3. End cap assembly; 31. End cap; 32. Insulating component; 321. Main body; 322. Protrusion; 322a. First protrusion; 322b. Second protrusion;

[0059] 4. Insulating film; 41. Weak part; 42. Recess; 43. Body part; 44. Pressure relief part;

[0060] 5. Pressure relief mechanism;

[0061] x, first direction; y, second direction; m, winding direction. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0063] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0064] In this application, the reference to "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 application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0065] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0066] In this application, 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 three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0067] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0068] In this application, "multiple" means two or more (including two).

[0069] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace, among other fields.

[0070] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0071] When a battery cell experiences thermal runaway from an adjacent cell or is affected by other severe heat sources, the rapid generation of heat causes the internal temperature of the battery cell to rise. The heated gas rushes towards the end cap assembly, causing partial melting and deformation of the end cap assembly, potentially puncturing the electrode assembly and leading to a short circuit. Therefore, an insulating film can be placed between the electrode assembly and the end cap assembly to reduce heat transfer and enhance the thermal insulation performance of the end cap assembly. While the insulating film reduces the occurrence of short circuits between the electrode assembly and the casing to some extent and protects the electrode assembly, applying an insulating film over a large area of ​​the end cap assembly can impede gas flow during thermal runaway of the battery cell. This can cause a large amount of gas to concentrate inside the electrode assembly, leading to casing cracking or even an explosion, thereby reducing the reliability of the battery cell. The above statements are only for providing background information related to this application and do not necessarily constitute prior art.

[0072] The battery cell provided in this application has an insulating film, at least partially disposed between the electrode body and the insulating components. This insulating film effectively restrains the electrode assembly, suppressing its contraction under heat, reducing short-circuit points, decreasing the likelihood of thermal runaway caused by short circuits, and improving the reliability of the battery cell. Furthermore, the insulating film has a higher melting point than the insulating components. In the event of thermal runaway, this reduces the risk of high-temperature gas directly impacting the insulating components, causing them to melt and deform, damaging the electrode assembly and leading to a short circuit. In addition, the insulating film has weak points. In the event of thermal runaway, gas can breach these weak points to reach the end cap assembly. Therefore, the insulating film does not obstruct gas transmission, reducing the risk of casing rupture due to electrode assembly expansion, and also reducing the risk of explosion caused by short circuits, further improving the reliability of the battery cell.

[0073] The battery cell described in this application is applicable to batteries and electrical devices that use batteries. This battery cell can be used, but is not limited to, batteries, and can also be used in products such as vehicles, aircraft, ships, electronic devices, and power tools, thereby improving the reliability of these products.

[0074] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, among others. 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.

[0075] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0076] See Figure 1 As shown, one embodiment of this application provides a vehicle 1000. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. In one embodiment of this application, the vehicle 1000 may include a motor 300, a controller 200, and a battery device 100. The controller 200 is used to control the battery device 100 to supply power to the motor 300. The motor 300 is connected to the wheels via a transmission mechanism, thereby driving the vehicle 1000. The battery device 100 can serve as the driving power source for the vehicle 1000, replacing or partially replacing gasoline or natural gas to provide driving power to the vehicle 1000. In one example, the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to supply power to the vehicle 1000. In one example, the battery device 100 can serve as the operating power source for the vehicle 1000's electrical system. For example, the battery device 100 can be used to meet the power needs of the vehicle 1000 during startup, navigation and operation.

[0077] Please refer to Figure 2 , Figure 2 Exploded views of battery devices provided in some embodiments of this application.

[0078] In some embodiments, the battery device 100 may include one or more battery cell assemblies for providing voltage and capacity.

[0079] A battery cell assembly may include multiple battery cells ( Figure 2 (Not shown), multiple battery cells are connected in series, parallel, or mixed connection through a busbar. Mixed connection refers to multiple battery cells being connected in both series and parallel.

[0080] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0081] As an example, a single battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0082] As an example, a battery cell can be 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 battery cells, such as hexagonal prismatic battery cells.

[0083] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module 1a, which is formed by arranging and fixing multiple battery cells to form an independent module. As an example, a battery module 1a can be formed by bundling multiple battery cells together with cable ties.

[0084] In some embodiments, the battery device 100 may be a battery pack, which includes a housing and one or more battery cell assemblies housed within the housing. As an example, the battery cell assembly may be a battery module 1a, which can be housed within the housing by securing the battery module 1a to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells to the housing.

[0085] In some embodiments, the housing is used to house individual battery cells, and the housing can have various structures.

[0086] In some embodiments, the housing may include a first housing 1b and a second housing 1c, which overlap each other, and together define a receiving space for accommodating a single battery cell. The second housing 1c may be a hollow structure with one open end, and the first housing 1b may be a plate-like structure, with the first housing 1b covering the open side of the second housing 1c so that the first housing 1b and the second housing 1c together define the receiving space. Alternatively, both the first housing 1b and the second housing 1c may be hollow structures with one open side, with the open side of the first housing 1b covering the open side of the second housing 1c. Of course, the housing formed by the first housing 1b and the second housing 1c can be of various shapes, such as a cylinder, a cuboid, etc.

[0087] In some embodiments, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the enclosure to house the individual battery cells. As an example, the frame may include multiple side beams.

[0088] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0089] In some embodiments, the battery device 100 may be an energy storage device.

[0090] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0091] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0092] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application.

[0093] In some embodiments, there are multiple battery cells 10, which are first connected in series, parallel, or mixed to form a battery module 1a. The multiple battery modules 1a are then connected in series, parallel, or mixed to form a whole and housed in a housing.

[0094] Multiple battery cells 10 in battery module 1a can be electrically connected through a busbar to achieve parallel, series, or mixed connection of the multiple battery cells 10 in battery module 1a. There can be one or more busbars, and each busbar is used to electrically connect at least two battery cells 10.

[0095] This application provides a battery cell 10, which includes a housing and an electrode assembly 10 housed within the housing.

[0096] In some embodiments, the outer casing may be a steel casing, an aluminum casing, or a composite metal casing (such as a copper-aluminum composite casing).

[0097] The outer shell can be a hollow structure, with an internal cavity for accommodating the electrode assembly 10 and the electrolyte.

[0098] In some embodiments, the casing of the battery cell 10 is a cylindrical casing, a square casing, a prismatic casing, or a casing of other shapes.

[0099] In some embodiments, the housing includes a housing and an end cap, the housing having an opening and the end cap being connected to the housing and covering the opening;

[0100] The housing is a component used to fit the end cap to form the internal cavity of the battery cell 10, which can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0101] The housing and end cap can be separate components. For example, an opening can be provided on the housing, and the end cap can be used to close the opening to form an internal cavity for the battery cell 10.

[0102] The housing can be of various shapes and sizes, such as cuboid or cylindrical. Specifically, the shape of the housing can be determined according to the specific shape and size of the electrode assembly 10. The housing can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0103] The shape of the end cap can be adapted to the shape of the housing to fit the housing. The material of the end cap can be the same as or different from that of the housing. Optionally, the end cap can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap is not easily deformed when subjected to compression and impact, so that the battery cell 10 can have higher structural strength and improve reliability.

[0104] The end caps are attached to the housing by welding, bonding, snap-fitting, or other means.

[0105] The housing may be open at one end or at both ends. In some examples, the housing may be a structure with an opening on one side, with one end cap fitting over the housing. In other examples, the housing may be a structure with openings on both sides, with two end caps fitting over the two openings of the housing, respectively.

[0106] Electrode assembly 10 is a component in the battery cell 10 where electrochemical reactions occur. The housing may contain one or more electrode assemblies 10.

[0107] In some embodiments, the electrode assembly 10 includes a positive electrode, a negative electrode, and a separator, wherein the positive electrode and the negative electrode have opposite polarities, and the separator separates the positive electrode and the negative electrode.

[0108] At least a portion of the separator is located between the positive and negative electrode plates. During the charging and discharging process of the battery cell 10, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrode plates. The separator, positioned between the positive and negative electrode plates, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0109] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0110] As an example, the positive current collector has two surfaces opposite each other in thickness, and the positive electrode film layer is disposed on either or both of the opposite surfaces of the positive current collector.

[0111] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0112] As an example, the positive electrode film layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0113] In some embodiments, the negative electrode may include a negative current collector.

[0114] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0115] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0116] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0117] As an example, the negative electrode film layer includes a negative electrode active material, which may be a negative electrode active material known in the art for use in battery cells. 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 oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0118] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0119] In some embodiments, the separator includes a separator membrane. The separator membrane in this application can be any known porous membrane with good chemical and mechanical stability.

[0120] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different.

[0121] Inorganic particle coating, organic particle coating, or organic / inorganic composite coating can also be applied to the surface of the separator.

[0122] The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surface of the positive or negative electrode.

[0123] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0124] In some embodiments, the battery cell 10 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0125] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0126] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0127] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0128] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0129] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0130] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0131] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0132] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0133] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0134] In some embodiments, the electrode assembly 10 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0135] In some embodiments, the electrode assembly 10 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0136] In some embodiments, the electrode assembly 10 has a stacked structure.

[0137] As an example, multiple positive and negative electrode plates can be set, with multiple positive and multiple negative electrode plates stacked alternately. As an example, multiple positive electrode plates can be set, and negative electrode plates are folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0138] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0139] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0140] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0141] In some embodiments, the positive current collector may include a positive tab, and the negative current collector may include a negative tab. The positive and negative tabs can be used to transmit current. As an example, at least a portion of the positive tab is not coated with a positive film layer, and at least a portion of the negative tab is not coated with a negative film layer.

[0142] See Figures 4 to 5 , Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a battery cell provided in an embodiment of this application; Figure 5 for Figure 4 The diagram shown is an enlarged structural schematic of a battery cell at point b, provided in an embodiment of this application.

[0143] like Figures 3 to 5 As shown, this application proposes a battery cell 10, which includes a housing 1, an electrode assembly 2, an end cap assembly 3, and an insulating film 4. The housing 1 has an opening. The electrode assembly 2 is disposed within the housing 1 and includes an electrode body 21 and a tab 22. The end cap assembly 3 includes an end cap 31 and an insulating component 32. The end cap 31 closes to the opening, and the insulating component 32 is disposed on the side of the end cap 31 facing the electrode assembly 2. The insulating film 4 is disposed within the housing 1, with at least a portion of the insulating film 4 located between the insulating component 32 and the electrode body 21. The melting point of the insulating film 4 is higher than the melting point of the insulating component 32. The insulating film 4 has a weak portion 41 located between the electrode body 21 and the insulating component 32.

[0144] Electrode assembly 2 includes electrode body 21. As an example, electrode body 21 includes a positive electrode film layer, a portion of the positive electrode current collector covered by the positive electrode film layer, a negative electrode film layer, a portion of the negative electrode current collector covered by the negative electrode film layer, and a separator.

[0145] The electrode assembly 2 also includes tabs 22. Tabs 22 extend from the electrode body 21.

[0146] In some examples, the tab 22 extends from one end of the electrode body 21.

[0147] In other examples, tabs 22 extend from opposite ends of electrode body 21.

[0148] In some examples, the tab 22 can be a positive tab and at least partially protrude to the outside of the electrode body 21.

[0149] In other examples, the tab 22 may be a negative tab and may protrude at least partially outward from the electrode body 21.

[0150] The end cap assembly 3 is a component used to cooperate with the housing 1 to form the internal cavity of the battery cell 10. The formed internal cavity can be used to accommodate the electrode assembly 2, the insulating film 4, and other components.

[0151] An insulating component 32 is located on the side of the end cap 31 facing the electrode assembly 2 to insulate and separate the end cap 31 from the electrode assembly 2. The insulating component 32 serves to provide insulation between the end cap 31 and the electrode assembly 2, thereby improving the safety performance of the battery cell 10. The insulating component 32 is made of an insulating material, such as plastic or PVC.

[0152] For example, the insulating component 32 and the end cap 31 can be connected by means of adhesive, snap-fit ​​or threaded connection.

[0153] The battery cell 10 also includes an insulating film 4, which is disposed inside the housing 1. At least part of the insulating film 4 is located between the insulating component 32 and the electrode body 21. The melting point of the insulating film 4 is higher than that of the insulating component 32. The insulating film 4 can be used to block the transfer of heat to the insulating film 4.

[0154] In some examples, at least part of the insulating film 4 is located between the insulating component 32 and the electrode body 21. The insulating film 4 can be connected to the inner wall surface of the insulating component 32, or to the electrode body 21, or to both the electrode body 21 and the insulating component 32.

[0155] In some examples, the insulating film 4 can be one or more, with multiple films spaced apart between the insulating component 32 and the electrode body 21.

[0156] The insulating film 4 can be connected to the electrode body 21 and the insulating component 32 in various ways. For example, the insulating film 4 can be connected to the electrode body 21 and the insulating component 32 by adhesive bonding; alternatively, the insulating film 4 can be connected to the electrode body 21 and the insulating component 32 by attachment.

[0157] In some embodiments, the insulating film 4 may be in the form of a sheet, block, strip, or other irregular shape.

[0158] In some embodiments, the insulating film 4 can be made of materials such as rubber and aramid, and has good heat insulation and insulation effects.

[0159] For example, the insulating film 4 is one of a polyimide film, a polyethylene terephthalate film, or a silicone film.

[0160] The insulating film 4 is provided with a weak portion 41. When the internal pressure of the battery cell 10 reaches a threshold, the weak portion 41 is configured to rupture or form a channel in the insulating film 4, so that gas can pass through the insulating film 4 to the end cap assembly 3 and be discharged from the end cap assembly 3 to the outside of the casing, thereby reducing the accumulation of gas in the electrode assembly 2.

[0161] In some embodiments, the structural strength of the weak portion 41 is less than that of other portions of the insulating film 4. For example, the thickness of the weak portion 41 is less than the thickness of other portions of the insulating film 4. Alternatively, the weak portion 41 is more easily pried open by gas than other portions of the insulating film 4.

[0162] The battery cell 10 provided in this application has an insulating film 4, at least partially disposed between the electrode body 21 and the insulating component 32. This insulating film 4 effectively restrains the electrode assembly 2, suppressing its contraction under heat, reducing short-circuit points, decreasing the likelihood of thermal runaway caused by short circuits, and improving the reliability of the battery cell 10. Furthermore, the melting point of the insulating film 4 is higher than that of the insulating component 32. In the event of thermal runaway in the battery cell 10, this reduces the risk of high-temperature gas directly impacting the insulating component 32, causing it to melt and deform, damaging the electrode assembly 2 and leading to a short circuit. In addition, the insulating film 4 has a weak point 41. In the event of thermal runaway, gas can breach the weak point 41 of the insulating film 4 to reach the end cap assembly 3. Therefore, the insulating film 4 does not obstruct the gas transmission path, reducing the risk of the casing 1 rupturing due to the expansion of the electrode assembly 2, and also reducing the risk of explosion caused by a short circuit, further improving the reliability of the battery cell 10.

[0163] See also Figure 6 , Figure 6 This is a schematic diagram of the end cap assembly and insulating film of a battery cell provided in an embodiment of this application.

[0164] According to one embodiment of this application, such as Figure 3 and Figure 6 As shown, the insulating component 32 includes a main body 321 and a protrusion 322. The main body 321 is attached to the end cap 31. The protrusion 322 protrudes from the surface of the main body 321 away from the end cap 31. In the arrangement direction of the electrode assembly 2 and the end cap assembly 3, at least a portion of the insulating film 4 is disposed between the protrusion 322 and the electrode body 21.

[0165] The insulating component 32 may include one protrusion 322 or multiple protrusions 322, with the multiple protrusions 322 spaced apart on the main body 321.

[0166] The main body 321 and the end cap 31 are stacked together along the thickness direction. The protrusion 322 protrudes from the surface of the main body 321 away from the end cap 31, and the end of the protrusion 322 away from the main body 321 can directly press against the electrode body 21; it can also press against the electrode body 21 through the insulating film 4.

[0167] In some examples, a protrusion 322 is provided at the end of the main body portion 321.

[0168] In other examples, a protrusion 322 is provided in the middle of the main body portion 321.

[0169] At least a portion of the insulating film 4 is disposed between the protrusion 322 and the electrode body 21 to prevent the protrusion 322 and the electrode body 21 from directly contacting each other.

[0170] In some examples, along the thickness direction of the end cap assembly 3, the projection of the insulating film 4 on the electrode body 21 covers the projection of the protrusion 322 on the electrode body 21.

[0171] In these alternative embodiments, at least a portion of the insulating film 4 is disposed between the protrusion 322 and the electrode body 21 to prevent the protrusion 322 from compressing the electrode assembly 2 after being deformed by heat, thereby reducing the risk of short circuit due to damage to the electrode assembly 2.

[0172] According to one embodiment of this application, such as Figure 4 and Figure 5 As shown, the protrusion 322 presses against the electrode body 21 through the insulating film 4.

[0173] In some examples, the insulating film 4 has a first surface and a second surface opposite to each other along its thickness direction. The first surface faces the insulating component 32 and is connected to the protrusion 322, while the second surface faces the electrode body 21 and is connected to the outer surface of the electrode body 21.

[0174] The protrusion 322 has surfaces opposite each other along the thickness direction, and the weak portion 41 is located on at least one surface.

[0175] In some examples, along the thickness direction of the end cap assembly 3, the weak portion 41 is located between the protrusion 322 and the electrode body 21. That is, along the thickness direction of the end cap assembly 3, the protrusion 322 and the weak portion 41 at least partially overlap.

[0176] For example, along the thickness direction of the end cap assembly 3, the projection of the weak portion 41 onto the electrode body 21 is less than or equal to the projection of the protrusion 322 onto the electrode body 21.

[0177] In these alternative embodiments, when the protrusion 322 presses against the electrode assembly 2 through the insulating film 4, the insulating film 4 plays an isolating role. The insulating film 4 can also buffer the pressure applied by the protrusion 322, so that the pressure is evenly distributed on the surface of the electrode body 21, reducing the damage to the electrode assembly 2 caused by excessive local pressure, and also reducing the occurrence of the insulating film 4 falling off.

[0178] According to one embodiment of this application, such as Figure 3 and Figure 6 As shown, the insulating component 32 includes multiple protrusions 322, each of which includes two first protrusions 322a and a second protrusion 322b. The two first protrusions 322a are disposed at opposite ends of the main body 321, and the second protrusion 322b is located between the two first protrusions 322a. The battery cell 10 includes multiple insulating films 4, which overlap with the first protrusions 322a and the second protrusion 322b respectively in the arrangement direction of the electrode assembly 2 and the end cap assembly 3.

[0179] For example, the plurality of protrusions 322 include two first protrusions 322a and a second protrusion 322b. The two first protrusions 322a are disposed at opposite ends of the main body portion 321, and the second protrusion 322b is located between the two first protrusions 322a. The battery cell 10 includes a plurality of insulating films 4, which include a first insulating film 4 and a second insulating film 4. In the arrangement direction of the electrode assembly 2 and the end cap assembly 3, the first insulating film 4 overlaps with the first protrusion 322a, and the second insulating film 4 overlaps with the second protrusion 322b.

[0180] Optionally, the first protrusion 322a and the second protrusion 322b have different structures.

[0181] Optionally, the area of ​​the insulating film 4 corresponding to the first protrusion 322a is greater than the area of ​​the insulating film 4 corresponding to the second protrusion 322b.

[0182] In these alternative embodiments, multiple insulating films 4 overlap with the first protrusion 322a and the second protrusion 322b respectively, forming multiple insulating protection systems. This distribution method can cover a wider range of areas where short circuit risks may occur.

[0183] According to one embodiment of this application, such as Figure 3 and Figure 6 As shown, the battery cell 10 also includes a pressure relief mechanism 5, which is disposed on the end cap 31 and located on the side of the second protrusion 322b away from the electrode body 21.

[0184] The pressure relief mechanism 5 is disposed on the end cap 31 and located on the side of the second protrusion 322b away from the electrode body 21. In the arrangement direction of the electrode assembly 2 and the end cap assembly 3, the pressure relief mechanism 5 and the second protrusion 322b at least partially overlap.

[0185] For example, the main body 321 is provided with a through hole at the position corresponding to the pressure relief mechanism 5, and the second protrusion 322b is connected to the pressure relief mechanism 5 through the through hole.

[0186] Optionally, the main body 321 is provided with multiple through holes, which are correspondingly provided with the pressure relief mechanism 5.

[0187] Combined with participation Figure 7 , Figure 7 This is a schematic diagram of the electrode assembly and insulating film of a battery cell provided in an embodiment of this application.

[0188] According to one embodiment of this application, such as Figure 6 and Figure 7 As shown, at least a portion of the insulating film 4 is attached to at least one of the electrode body 21 and the insulating component 32.

[0189] In some examples, the insulating film 4 is attached to the insulating component 32.

[0190] Optionally, the insulating film 4 is attached to the outer surface of the protrusion 322 and connected to the main body 321 surrounding the protrusion 322.

[0191] In other examples, the insulating film 4 is attached to the outer surface of the electrode body 21. The outer surface of the electrode body 21 is a spacer located at the outermost edge of the electrode body 21.

[0192] For example, the insulating film 4 has a first surface and a second surface along its own thickness direction. The first surface faces the electrode body 21 and is attached to the outer surface of the electrode body 21, and the second surface faces the insulating component 32 and can be attached to the surface of the insulating component 32.

[0193] In these alternative embodiments, by attaching the insulating film 4 to the electrode body 21, the insulating film 4 can not only increase the thickness of the area and strengthen the adhesion between the insulating member and the electrode sheet, but also hold the insulating member located at the outermost ring of the electrode assembly 2, suppressing its shrinkage behavior when heated and reducing short circuit points.

[0194] According to one embodiment of this application, such as Figure 3 and Figure 7 As shown, the electrode body 21 has an end face 211 facing the end cap assembly 3, and the tab 22 extends from the end face 211. An insulating film 4 is attached to the end face 211 of the electrode body 21.

[0195] The electrode body 21 has an end face 211 facing the end cap 31, and the electrode tab 22 extends from the end face 211, so that the electrode tab 22 is located between the electrode body 21 and the end cap 31 and is located on the same side of the electrode body 21.

[0196] The insulating film 4 is attached to the end face 211 of the electrode body 21. This can be understood as the insulating film 4 being attached only to the end face 211 of the electrode body 21, or a portion of the insulating film 4 being attached to the end face 211 of the electrode body 21.

[0197] In some examples, the insulating member 32 includes a body portion 321 and a protrusion 322. An insulating film 4 is attached to the end face 211 of the electrode body 21, and the insulating film 4 is at least partially located on the protrusion 322 and the end face 211.

[0198] For example, the insulating film 4 covers the end face 211 of the electrode body 21 and avoids the tab 22.

[0199] In these alternative embodiments, the insulating film 4 is configured such that the end face 211 of the electrode body 21 has a large contact area, which can increase the connection stability between the insulating film 4 and the electrode body 21. Moreover, the attachment of the insulating film 4 to the end face 211 can help improve the sealing performance of the battery cell 10 and reduce the leakage of electrolyte in the battery cell 10 to a certain extent.

[0200] According to one embodiment of this application, such as Figure 3 and Figure 7 As shown, the electrode body 21 also includes an outer peripheral surface 212 surrounding the end face 211, and the outer peripheral surface 212 is connected to the end face 211. The insulating film 4 is also attached to the outer peripheral surface 212.

[0201] The electrode body 21 includes an end face 211 and an outer peripheral face 212. The outer peripheral face 212 is connected to the end face 211 and is disposed on the side of the end face 211 away from the end cover 31.

[0202] In some examples, the electrode assembly 2 is a wound structure formed by winding a positive electrode, an insulator and a negative electrode, with the outer peripheral surface 212 being the outermost ring of the electrode assembly 2.

[0203] Optionally, the electrode body 21 has a wound structure, and the outer peripheral surface 212 of the electrode body 21 includes a main body segment and two bent segments, which are opposite each other along the arrangement direction perpendicular to the electrode assembly 2 and the end cap assembly 3. The insulating film 4 can be attached to the main body segment, and the insulating film 4 can also be attached to the bent segments.

[0204] For example, the electrode assembly 2 includes an electrode body 21 and a tab 22. The electrode body 21 includes an end face 211 and an outer peripheral face 212. The insulating film 4 includes a first insulating portion and a second insulating portion. The first insulating portion is attached to the end face 211 and the second insulating portion is attached to the outer peripheral face 212.

[0205] In some examples, the insulating film 4 is attached to the outer peripheral surface 212. For example, the insulating film 4 may be disposed along the height direction of the outer peripheral surface 212, which is parallel to the arrangement direction of the electrode assembly 2 and the end cap assembly 3. Alternatively, the insulating film 4 may be disposed circumferentially along the outer peripheral surface 212.

[0206] In these alternative embodiments, the insulating film 4 is attached to the outer peripheral surface 212, reducing the possibility of the outer peripheral surface 212 forming a conductive path with surrounding components, thereby reducing the risk of short circuit.

[0207] According to one embodiment of this application, such as Figure 3 and Figure 7 As shown, the outer peripheral surface 212 includes two first surfaces 2121 disposed opposite each other along a first direction x and two second surfaces 2122 disposed opposite each other along a second direction y. The second surfaces 2122 are connected to the two adjacent first surfaces 2121. The second surfaces 2122 are at least partially arc-shaped, and the second direction y is perpendicular to the first direction x. At least a portion of the insulating film 4 is attached to the second surfaces 2122.

[0208] For example, the outer peripheral surface 212 includes two flat surfaces arranged opposite each other along a first direction x and two arcuate surfaces arranged opposite each other along a second direction y. The arcuate surfaces connect two adjacent flat surfaces. The second direction y is perpendicular to the first direction x. The area of ​​the arcuate surfaces is smaller than the area of ​​the flat surfaces. The insulating film 4 is attached to the arcuate surfaces.

[0209] Optionally, the insulating film 4 is attached to the second surface 2122 and extends in a direction away from the end face 211.

[0210] In these optional embodiments, the insulating film 4 is attached to the second surface 2122 of the outer peripheral surface 212 disposed along the second direction y, which reduces the volume occupied by the insulating film 4, making the structure of the insulating film 4 compact and the overall space occupied smaller, thereby improving the overall layout compactness of the battery cell 10 and increasing the energy density of the battery cell 10.

[0211] According to one embodiment of this application, the insulating film 4 is also attached to the first surface 2121.

[0212] Exemplarily, the insulating component 32 includes a main body 321 and a second protrusion 322b, the main body 321 being attached to the end cap 31. The second protrusion 322b protrudes from the surface of the main body 321 away from the end cap 31. The battery cell 10 includes a pressure relief mechanism 5, which is disposed on the end cap 31 and located on the side of the second protrusion 322b away from the electrode body 21. The electrode body 21 includes an end face 211 and an outer peripheral surface 212 connecting the end face 211. The outer peripheral surface 212 includes a first surface 2121 and a second surface 2122. A portion of the insulating film 4 is attached to the end face 211 and located between the end face 211 and the second protrusion 322b, and another portion of the insulating film 4 is attached to the first surface 2121.

[0213] See also Figure 8 , Figure 8 This is a partial structural schematic diagram of the electrode assembly and insulating film of a battery cell provided in an embodiment of this application.

[0214] According to one embodiment of this application, such as Figure 3 , Figure 7 and Figure 8 As shown, the electrode body 21 includes a first electrode body 213, and the electrode tab 22 includes a first electrode tab 221. The first electrode body 213 includes a base portion 2131 and a thinned portion 2132, the thinned portion 2132 being connected between the base portion 2131 and the first electrode tab 221, and at least a portion of the thickness of the thinned portion 2132 being less than the thickness of the base portion 2131. In the thickness direction of the first electrode body 213, the portion of the insulating film 4 attached to the outer peripheral surface 212 at least partially overlaps with the thinned portion 2132.

[0215] When the insulating film 4 is attached to the outer peripheral surface 212, the insulating film 4 overlaps at least partially with the thinned portion 2132 in the thickness direction of the first electrode body 213.

[0216] The first electrode may include a current collector and an active material layer disposed on at least one surface of the current collector. The portion having the active material constitutes the first electrode body 213, and the portion without the active material constitutes the tab 22. The tabs 22 may be located together at one end of the first electrode body 213 or separately at both ends of the first electrode body 213. The thickness of the active material layer varies in different regions. Typically, the thickness of the active material layer at the ends is less than the thickness of the active material layer in the middle. Therefore, the first electrode body 213 includes a base portion 2131 and a thinned portion 2132, both of which have an active material layer. The thickness of the active material layer in the thinned portion 2132 is less than the thickness of the active material layer in the base portion 2131.

[0217] In some examples, the electrode body 21 further includes a second electrode body and a spacer, and the electrode tab 22 further includes a second electrode tab. The second electrode body includes a second base portion 2131 and a second thinned portion 2132, the second thinned portion 2132 being connected between the second base portion 2131 and the second electrode tab, and at least a portion of the thickness of the second thinned portion 2132 being less than the thickness of the second base portion 2131. The spacer is at least disposed between the first electrode body 213 and the second electrode body. The first electrode body 213 and the second electrode body have opposite polarities.

[0218] In some examples, the first electrode body 213 may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0219] In other examples, the first electrode body 213 may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0220] In the thickness direction of the first electrode body 213, the insulating film 4 and the thinned portion 2132 at least partially overlap. It can be understood that the insulating film 4 and the thinned portion 2132 are at least partially opposite each other in the thickness direction.

[0221] In some examples, the insulating film 4 is attached to the outer peripheral surface 212 of the electrode body 21, and a portion of the insulating film 4 overlaps with the thinned portion 2132 in the thickness direction of the first electrode body 213.

[0222] In other examples, the insulating film 4 is attached to the outer peripheral surface 212 of the electrode body 21, and in the thickness direction of the first electrode body 213, the insulating film 4 overlaps only with the thinned portion 2132.

[0223] In these alternative embodiments, due to the presence of the thinned portion 2132 and the uneven distribution of expansion and contraction forces during long-term use of the electrode assembly 2, there is a defect in the poor adhesion between the insulating member and the first electrode. Therefore, by attaching the insulating film 4 to the outer surface of the electrode body 21 and at least partially overlapping the thinned portion 2132, not only can the rate at which external heat sources transfer heat to this area be slowed down, but the contraction of the insulating member can also be suppressed, further reducing the risk of short circuits due to lack of insulation protection of the electrode.

[0224] See also Figure 9 , Figure 9 This is a schematic diagram of the structure of the insulating film of a battery cell provided in an embodiment of this application.

[0225] According to one embodiment of this application, such as Figure 9 As shown, the insulating film 4 has a recess 42, and the portion of the insulating film 4 corresponding to the bottom surface of the recess 42 forms a weak portion 41.

[0226] The insulating film 4 has a first surface and a second surface disposed opposite each other in its thickness direction, and the distance between the first surface and the second surface is the thickness of the insulating film 4. The thickness of the weak portion 41 is less than the thickness of other parts of the insulating film 4.

[0227] In some examples, the weak part 41 is a weak area of ​​the insulating film 4. During the manufacturing process, a thinner weak area is usually processed in a certain area of ​​the insulating film 4.

[0228] For example, a certain thickness of material is cut and removed from the insulating film 4 using a tool to form a weak part 41.

[0229] For example, a certain area of ​​the insulating film 4 is stamped into a thinner area to form a weak portion 41.

[0230] For example, a certain area of ​​the insulating film 4 is milled into a thinner area to form a weak part 41.

[0231] For example, a certain area of ​​the insulating film 4 is etched into a thinner area to form a weak portion 41.

[0232] In these alternative embodiments, the thinner weak portion 41 is preferentially fractured when subjected to thermal shock, allowing high-temperature gas to pass through the insulating film 4, reducing the risk of the housing 1 rupturing due to the expansion of the electrode assembly 2.

[0233] According to one embodiment of this application, the thickness m of the weak portion 41 and the maximum thickness d of the insulating film 4 satisfy the following condition: 60% ≤ m / d ≤ 90%.

[0234] In some examples of this application, the thickness m of the weak portion 41 and the maximum thickness d of the insulating film 4 satisfy m / d as 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, or other ranges formed by any two of the above endpoints.

[0235] Optionally, the thickness m of the weak part 41 and the maximum thickness d of the insulating film 4 satisfy the following condition: 70% ≤ m / d ≤ 80%.

[0236] In these alternative embodiments, the weak portion 41 has a suitable thickness that allows it to be blasted open by gas in the event of thermal runaway, while also providing a certain degree of thermal insulation to protect the integrity of the insulating component 32 structure.

[0237] See also Figure 10 , Figure 10 This is a schematic diagram of the structure of the insulating film of a battery cell provided in another embodiment of this application.

[0238] According to one embodiment of this application, such as Figure 10 As shown, the insulating film 4 includes a body portion 43 and a pressure relief portion 44. A weak portion 41 is provided along the outer periphery of the pressure relief portion 44, and the weak portion 41 is connected to the body portion 43 and the pressure relief portion 44.

[0239] When the pressure or temperature of the battery cell 10 reaches a threshold, the pressure relief section 44 is blasted open along the edge of the weak section 41 to form a channel for gas flow.

[0240] In some examples, the weak part 41 is a circular scratch, and the pressure relief part 44 is the area enclosed by the circular scratch.

[0241] In other examples, the weak part 41 is a semi-circular scratch, and the pressure relief part 44 is a semi-circular scratch and the area enclosed by the line connecting the two ends of the semi-circle.

[0242] In some other examples, the weak part 41 is a V-shaped scratch, and the pressure relief part 44 is a V-shaped scratch and the area enclosed by the line connecting the two ends of the V.

[0243] Optionally, the pressure relief portion 44 has the same thickness as the main body portion 43.

[0244] In these alternative embodiments, when thermal runaway occurs, the pressure relief section 44 can, with the help of the weak section 41, separate from the main body section 43 first after the gas reaches a certain pressure threshold, thereby providing a release channel for the internal high-pressure gas, etc., and reducing the possibility of shell rupture or even more serious damage caused by excessive pressure.

[0245] According to one embodiment of this application, the projection of the weak portion 41 in the direction perpendicular to the thickness of the insulating film 4 is at least partially arc-shaped.

[0246] In some examples, the projection of the weak portion 41 onto a cross section perpendicular to the thickness direction of the insulating film 4 is a semicircle.

[0247] In some other examples, the projection of the weak portion 41 onto a cross section perpendicular to the thickness direction of the insulating film 4 is fan-shaped.

[0248] In these alternative embodiments, the weak portion 41 is configured in such a way that it is easy to manufacture.

[0249] See conclusion Figure 11 , Figure 11 This is a schematic diagram of the electrode assembly and insulating film of a battery cell provided in another embodiment of this application.

[0250] According to one embodiment of this application, such as Figure 3 and Figure 11 As shown, the electrode assembly 2 includes a first electrode 2a, a second electrode 2b, and a separator 2c. The first electrode 2a and the second electrode 2b have opposite polarities. The separator 2c is used to isolate the first electrode 2a and the second electrode 2b. The first electrode 2a, the second electrode 2b, and the separator 2c are wound along the winding direction m to form the electrode assembly 2. The protruding direction of the arc-shaped weak portion 41 is consistent with the winding direction m of the portion of the electrode assembly 2 overlapping with the weak portion 41.

[0251] In some examples, the wound electrode assembly 2 includes a flat region and a bent region connected to both ends of the flat region. A first part of the insulating film 4 is bonded to the end face 211 located in the flat region, and a second part of the insulating film 4 is bonded to the end face 211 located in the bent region. The protruding direction of the arc-shaped weak portion 41 provided on the first part is consistent with the winding direction m of the overlapping part of the electrode assembly 2 and the weak portion 41 in the flat region. The protruding direction of the arc-shaped weak portion 41 provided on the second part is consistent with the winding direction m of the overlapping part of the electrode assembly 2 and the weak portion 41 in the bent region.

[0252] In these alternative embodiments, the protruding direction of the arc-shaped weak portion 41 and the winding direction m of the overlapping portion of the electrode assembly 2 and the weak portion 41 are aligned, reducing the risk of the pressure relief portion 44 and the weak portion 41 being squeezed out of the electrode assembly 2, and improving the effectiveness of heat insulation and insulation of the insulating component 32.

[0253] According to one embodiment of this application, the thickness of the insulating film 4 is 20 μm to 100 μm.

[0254] In some examples of this application, the thickness of the insulating film 4 is 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, 50 μm, 51 μm, 52 μm, 53 μm, 54 μm, 55 μm, 56 μm, 57 μm, 58 μm, 59 μm, and 60 μm. 61μm, 62μm, 63μm, 64μm, 65μm, 66μm, 67μm, 68μm, 69μm, 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76μm, 77μm, 78μm, 79μm, 80μm, 81μm, 82μm, 83μm, 84μm, 85μm, 86μm, 87μm, 88μm, 89μm, 90μm, 91μm, 92μm, 93μm, 94μm, 95μm, 96μm, 97μm, 98μm, 99μm, 100μm, or other ranges formed by any two of the above endpoints.

[0255] Secondly, this application provides a battery device including the aforementioned battery cell 10.

[0256] Thirdly, this application provides an electrical device, including the aforementioned battery cell 10 or the aforementioned battery device, wherein the battery cell 10 or the battery device is used to store or provide electrical energy.

[0257] According to some embodiments of this application, see Figures 3 to 7 , Figure 10 As shown, this application provides a battery cell 10

[0258] The battery cell 10 includes a housing 1, an electrode assembly 2, an end cap assembly 3, a pressure relief mechanism 5, and multiple insulating films 4.

[0259] The housing 1 has an opening.

[0260] Electrode assembly 2 is disposed within housing 1. Electrode assembly 2 includes electrode body 21 and electrode tab 22. Electrode body 21 has an end face 211 facing end cap assembly 3 and an outer peripheral surface 212 surrounding end face 211. Electrode tab 22 extends from end face 211. Outer peripheral surface 212 includes two first surfaces 2121 disposed opposite each other along a first direction x and two second surfaces 2122 disposed opposite each other along a second direction y. The second surfaces 2122 are connected to adjacent first surfaces 2121. The second surfaces 2122 are at least partially arc-shaped. The second direction y is perpendicular to the first direction x. Electrode body 21 includes first electrode body 213, and electrode tab 22 includes first electrode tab 221. First electrode body 213 includes a base portion 2131 and a thinned portion 2132. Thinned portion 2132 is connected between base portion 2131 and first electrode tab 221. At least a portion of the thickness of thinned portion 2132 is less than the thickness of base portion 2131.

[0261] The end cap assembly 3 includes an end cap 31 and an insulating member 32. The end cap 31 closes to the opening, and the insulating member 32 is disposed on the side of the end cap 31 facing the electrode assembly 2. The insulating member 32 includes a main body portion 321 and a plurality of protrusions 322. The main body portion 321 is attached to the end cap 31. The protrusions 322 protrude from the surface of the main body portion 321 away from the end cap 31. The plurality of protrusions 322 includes two first protrusions 322a and a second protrusion 322b. The two first protrusions 322a are disposed at opposite ends of the main body portion 321, and the second protrusion 322b is located between the two first protrusions 322a.

[0262] The pressure relief mechanism 5 is provided on the end cap 31 and is located on the side of the second protrusion 322b away from the electrode body 21.

[0263] An insulating film 4 is disposed within the housing 1, with at least a portion of the insulating film 4 located between the insulating component 32 and the electrode body 21. The melting point of the insulating film 4 is higher than that of the insulating component 32. The protrusion 322 presses against the electrode body 21 through the insulating film 4. Multiple insulating films 4 overlap with the first protrusion 322a and the second protrusion 322b, respectively. The insulating film 4 includes a main body portion 321, a pressure relief portion 44, and a weak portion 41, with the weak portion 41 disposed between the electrode body 21 and the insulating component 32. The weak portion 41 is disposed along the outer periphery of the pressure relief portion 44 and is connected to the main body portion 43 and the pressure relief portion 44. The projection of the weak portion 41 in the direction perpendicular to the thickness of the insulating film 4 is at least partially arc-shaped.

[0264] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The battery cell includes: a housing having an opening; an electrode assembly disposed in the housing, the electrode assembly including an electrode body and a tab; an end cap assembly including an end cap and an insulating member, the end cap covering the opening, the insulating member disposed on a side of the end cap facing the electrode assembly; an insulating film disposed in the housing, at least part of the insulating film being located between the insulating member and the electrode body, the insulating film having a melting point higher than that of the insulating member, the insulating film being provided with a weak portion, the weak portion being disposed between the electrode body and the insulating member.

2. The battery cell of claim 1, wherein, The insulating member includes: a main body portion attached to the end cap; a protruding portion protruding from a surface of the main body portion away from the end cap, at least part of the insulating film being disposed between the protruding portion and the electrode body in a direction in which the electrode assembly and the end cap assembly are arranged.

3. The battery cell according to claim 2, wherein the protruding portion is pressed against the electrode body by the insulating film.

4. The battery cell according to claim 2, wherein the insulating member includes a plurality of the protruding portions, the plurality of the protruding portions including two first protruding portions disposed at opposite ends of the main body portion and a second protruding portion located between the two first protruding portions; the battery cell includes a plurality of the insulating films, the plurality of the insulating films respectively overlapping the first protruding portions and the second protruding portion in the direction in which the electrode assembly and the end cap assembly are arranged.

5. The battery cell according to claim 4, wherein the battery cell further includes a pressure relief mechanism disposed on the end cap on a side of the second protruding portion away from the electrode body.

6. The battery cell according to claim 1, wherein at least part of the insulating film is attached to at least one of the electrode body and the insulating member.

7. The battery cell according to claim 6, wherein the electrode body has an end surface facing the end cap assembly, the tab extending from the end surface; the insulating film is attached to the end surface of the electrode body.

8. The battery cell according to claim 7, wherein the electrode body further includes an outer peripheral surface disposed around the end surface, the outer peripheral surface being connected to the end surface; the insulating film is further attached to the outer peripheral surface.

9. The battery cell according to claim 8, wherein the outer peripheral surface includes two first surfaces disposed opposite to each other in a first direction and two second surfaces disposed opposite to each other in a second direction, the second surfaces being connected to adjacent two of the first surfaces, the second surfaces being at least partially arc-shaped, the second direction being perpendicular to the first direction; at least part of the insulating film is attached to the second surfaces.

10. The battery cell according to claim 9, wherein the insulating film is further attached to the first surfaces.

11. The battery cell according to claim 8, wherein the electrode body includes a first electrode tab body, the tab including a first tab. The first tab body includes a base portion and a thinned portion, the thinned portion being connected between the base portion and the first tab, at least a portion of the thinned portion having a thickness smaller than a thickness of the base portion; In a thickness direction of the first tab body, a portion of the insulating film attached to the outer circumferential surface at least partially overlaps the thinned portion.

12. The battery cell according to claim 1, wherein The insulating film is provided with a recess, and a portion of the insulating film corresponding to a bottom surface of the recess forms the weak portion.

13. The battery cell according to claim 12, wherein A thickness m of the weak portion and a maximum thickness d of the insulating film satisfy 60%≤m / d≤90%.

14. The battery cell according to claim 1, wherein The insulating film includes a body portion and a pressure relief portion, the weak portion is provided along an outer periphery of the pressure relief portion, and the weak portion is connected between the body portion and the pressure relief portion.

15. The battery cell according to claim 14, wherein The weak portion is at least partially arc-shaped in a projection perpendicular to a thickness direction of the insulating film.

16. The battery cell according to claim 15, wherein The electrode assembly includes a first tab, a second tab, and a separator, the first tab and the second tab having opposite polarities, the separator separating the first tab and the second tab, the first tab, the second tab, and the separator being wound in a winding direction to form the electrode assembly; An extending direction of the arc-shaped weak portion and the winding direction of a portion of the electrode assembly overlapping the weak portion are identical.

17. A battery device characterized by comprising: A plurality of battery cells according to any one of claims 1 to 16 are included.

18. An electrical device, comprising: A battery cell according to any one of claims 1 to 16 or a battery device as recited in claim 17 is used for storing or providing electric energy.

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