Current collector, battery cell, battery and electric device

Abstract

A current collector (100), a battery cell (200), a battery (300), and an electric device (400), the current collector (100) comprising: a conductive layer (10) for outputting a current; the base material layer (20) is attached to a part of the conductive layer (10), the melting point of the base material layer (20) is smaller than that of the conductive layer (10), and the base material layer (20) is configured to be shrunk and fractured when heated, so that the conductive layer (10) is fractured to form a through hole (21).

Description

Current collector, battery cell, battery and electrical device Technical Field

[0001] The present application relates to the field of batteries, and in particular to a current collector, a battery cell, a battery, and an electrical device. Background Art

[0002] In the related technology, the existing battery cell includes a positive electrode sheet, a negative electrode sheet and a separator. The separator is arranged between the positive electrode sheet and the negative electrode sheet. During the charging process of the battery cell, dendrites are deposited on the surface of the negative electrode sheet. After the dendrites pierce the separator, they come into contact with the active material layer on the positive electrode sheet, causing a short circuit in the battery cell, which can easily cause thermal runaway of the battery cell and reduce the reliability of the battery cell.

[0003] Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of this application is to propose a current collector. During the battery charging process, when dendrites formed on the current collector pierce the separator, causing the battery cells to short-circuit and generate heat, through-holes are formed in the current collector, thereby reducing the risk of heat diffusion to the current collector and improving the reliability of the battery cells.

[0005] The present application further proposes a battery cell.

[0006] The present application further proposes a battery.

[0007] The present application further proposes an electrical device.

[0008] In a first aspect, an embodiment of the present application provides a current collector, comprising:

[0009] A conductive layer for outputting current;

[0010] A substrate layer, attached to a portion of the conductive layer,

[0011] The melting point of the base material layer is lower than that of the conductive layer, and the base material layer is configured to shrink and break when heated, thereby breaking the conductive layer to form a through hole.

[0012] In the above technical solution, by setting the melting point of the substrate layer to be lower than the melting point of the conductive layer, during the charging process of the battery cell, the dendrites formed on the current collector pierce the isolation membrane, causing the battery cell to short-circuit and generate heat. The substrate layer shrinks and breaks when heated, causing the conductive layer to break to form a through hole, thereby disconnecting the short-circuited positive and negative poles, which can reduce the risk of thermal runaway of the battery cell and improve the reliability of the battery cell.

[0013] In some embodiments, the melting point of the substrate layer is A, satisfying the relationship: 110°C≤A≤130°C.

[0014] In the above technical solution, by setting the melting point of the substrate layer to A, the substrate layer can have a lower melting point. After the battery cell short-circuits and generates heat, the substrate layer can shrink and break, thereby forming a through hole on the current collector. Moreover, when the battery cell is working normally, the substrate layer will not break.

[0015] In some embodiments, the elastic modulus of the substrate layer is B, which satisfies the relationship: B≥15 MPa.

[0016] In the above technical solution, by setting the elastic modulus of the substrate layer to B, the substrate layer can have appropriate shrinkage, which is conducive to the shrinkage and fracture of the substrate layer after the battery cell short-circuits and generates heat.

[0017] In some embodiments, the current collector further includes a separator, which is disposed on the substrate layer and is used to separate the substrate layer into multiple regions. The melting point of the separator is higher than that of the substrate layer.

[0018] In the above technical solution, by setting a separator, after a short circuit occurs in the battery cell, heat is transferred to the area on the current collector opposite to the dendrite, forming a through hole on the current collector. Since the separator is arranged on the substrate layer, the separator will prevent the through hole from continuing to expand. After the through hole is formed on the current collector, it can continue to be used, thereby extending the service life of the current collector.

[0019] In some embodiments, the separators are used to divide the substrate layer into grid-like regions.

[0020] In the above technical solution, the substrate layer is divided into grid-like areas by separators. After heat is transferred to the substrate layer to form through holes on the current collector, the separators will prevent the through holes from continuing to expand. The current collector can continue to be used after the through holes are formed, further extending the service life of the current collector. In addition, the separators better prevent heat from diffusing to other areas on the substrate layer, and transfer heat to the position on the substrate layer opposite to the dendrites, reducing the heat transferred to other areas on the substrate layer, further reducing the risk of heat diffusion to the current collector, further reducing the spread of heat on the current collector, further reducing the spread of thermal runaway in the battery cell, and further improving the reliability of the battery cell.

[0021] In some embodiments, the separator is disposed on a surface of the substrate layer and is located between the substrate layer and the conductive layer.

[0022] In the above technical solution, by arranging the separator between the substrate layer and the conductive layer, when heat is transferred from the conductive layer to the substrate layer, the separator better prevents the heat from diffusing to other areas on the substrate layer, and transfers the heat to the position on the substrate layer opposite to the dendrite, reducing the heat transfer to other areas on the substrate layer, further reducing the risk of heat diffusion to the current collector, further reducing the spread of heat on the current collector, further reducing the spread of thermal runaway in the battery cell, and further improving the reliability of the battery cell. Moreover, after the heat is transferred to the substrate layer to form a through hole on the current collector, the separator will prevent the through hole from continuing to expand.

[0023] In some embodiments, the separator is formed as a coating; or the separator is adhered to the substrate layer.

[0024] In the above technical solution, the separator is coated on the outer surface of the substrate layer, thereby forming a separator coating on the outer surface of the substrate layer, thereby achieving the effect of assembling the separator on the substrate layer, making assembly of the separator and the substrate layer simple and convenient. The separator is adhered to the substrate layer, thereby fixing the separator to the outer surface of the substrate layer, reducing the risk of separation of the separator from the substrate layer.

[0025] In some embodiments, the separator is embedded inside the substrate layer.

[0026] In the above technical solution, by embedding the separator inside the substrate layer, the separator better prevents heat from diffusing to other areas on the substrate layer, so that the heat is concentrated on the position opposite to the dendrite on the substrate layer, accelerating the shrinkage rate of this position, and at the same time reducing the risk of heat transfer to other areas on the substrate layer, reducing the risk of heat diffusion to the current collector, thereby further reducing the spread of heat on the current collector, reducing the spread of thermal runaway in the battery cell, and improving the reliability of the battery cell.

[0027] In some embodiments, the ratio of the thickness of the separator to the thickness of the substrate layer is C, which satisfies the relationship: 0.8≤C≤1.1.

[0028] In the above technical solution, by setting the ratio of the thickness of the separator to the thickness of the substrate layer to C, the proportion of the separator in the current collector can be made appropriate while ensuring the performance of the separator.

[0029] In some embodiments, the melting point of the separator is D, satisfying the relationship: 180°≤D.

[0030] In the above technical solution, by setting the melting point of the separator to D, it is possible to ensure that the melting point of the separator is higher than the melting point of the substrate layer. After a short circuit occurs in the battery cell, heat is transferred to the area on the current collector opposite to the dendrite, forming a through hole on the current collector. Since the melting point of the separator is higher than the melting point of the substrate layer, the risk of the separator melting can be reduced.

[0031] In some embodiments, the separator is a polyimide member.

[0032] In the above technical solution, by setting the separator to be a polyimide member, it is not easy to break when heated, so that the separator can have reliable working performance.

[0033] In some embodiments, the conductive layer completely wraps around the outer peripheral wall of the substrate layer.

[0034] In the above technical solution, by completely wrapping the conductive layer around the outer peripheral wall of the substrate layer, the arrangement area of ​​the conductive layer can be increased, and the output current capacity of the current collector can be improved.

[0035] In some embodiments, the conductive layer is a metal coating provided on the substrate layer; or the conductive layer is adhered to the substrate layer.

[0036] In the above technical solution, the conductive layer is coated on the outer surface of the substrate layer, thereby forming a conductive layer coating on the outer surface of the substrate layer, thereby achieving the effect of assembling the conductive layer on the substrate layer, making the assembly of the separator and the substrate layer simple and convenient. The conductive layer is adhered to the substrate layer, thereby fixing the conductive layer to the outer surface of the substrate layer, reducing the risk of separation of the conductive layer and the substrate layer.

[0037] In some embodiments, the current collector further includes a first insulating layer, which is disposed on a first surface of the conductive layer away from the substrate layer. The first insulating layer is used to divide the first surface into multiple regions, and the melting point of the first insulating layer is higher than that of the conductive layer.

[0038] In the above technical solution, by setting a first insulating layer, the first insulating layer divides the first surface into multiple areas. The first insulating layer can reduce the diffusion of heat to other areas on the substrate layer, and transfer heat to the position opposite to the dendrite on the substrate layer, while further reducing the risk of heat diffusion to the current collector, thereby reducing the spread of thermal runaway in the battery cell and improving the reliability of the battery cell.

[0039] In some embodiments, the first insulating layer includes a plurality of intersecting insulating strips to define a grid-like region.

[0040] In the above technical solution, a grid-like area is defined on the first surface by multiple insulating strips. When heat is transferred to the conductive layer, the insulating strips better prevent the heat from diffusing to other areas on the conductive layer, so that the heat is transferred to the position on the conductive layer opposite to the dendrites, thereby transferring the heat to the position on the substrate layer opposite to the dendrites, reducing the heat transferred to other areas on the substrate layer, further reducing the risk of heat diffusion to the current collector, further reducing the spread of heat on the current collector, further reducing the spread of thermal runaway in the battery cell, and further improving the reliability of the battery cell.

[0041] In some embodiments, the first insulating layer is formed as a coating; or the first insulating layer is adhered to the conductive layer.

[0042] In the above technical solution, the first insulating layer is coated on the first surface of the conductive layer, thereby forming a first insulating layer coating on the first surface, thereby achieving the effect of assembling the first insulating layer on the conductive layer, making assembly of the first insulating layer and the conductive layer simple and convenient. The first insulating layer is adhered to the conductive layer, thereby fixing the first insulating layer to the outer surface of the conductive layer, reducing the risk of separation of the conductive layer and the first insulating layer.

[0043] In a second aspect, an embodiment of the present application provides a battery cell, comprising:

[0044] The positive electrode sheet and the negative electrode sheet, at least one of the positive electrode sheet and the negative electrode sheet includes the above-mentioned current collector.

[0045] In the above technical solution, at least one of the positive and negative electrodes includes the current collector of the above embodiment. During the charging process of a battery cell, when a short circuit occurs between the positive and negative electrodes, heat is generated after the short circuit. The heat is transferred to the current collector, causing the substrate layer to shrink and fracture when heated. When the substrate layer fractures, the conductive layer fractures to form a through-hole. For example, after the heat is transferred to the current collector, the substrate layer shrinks and fractures at the position opposite the dendrite, causing the conductive layer to fracture at the position opposite the dendrite, thereby forming a through-hole in the current collector and disconnecting the positive and negative electrodes. The through-hole penetrates the current collector in the thickness direction of the current collector, reducing the risk of heat diffusion to the current collector, reducing the spread of heat on the current collector, reducing the spread of thermal runaway in the battery cell, and improving the reliability of the battery cell.

[0046] In some embodiments, the negative electrode sheet is provided with a current collector.

[0047] In the above technical solution, a current collector is provided through the negative electrode sheet. During the charging process of the battery cell, after the positive electrode sheet and the negative electrode sheet are short-circuited, heat is transferred to the negative electrode sheet, and a through hole is formed in the negative electrode sheet, which reduces the risk of heat diffusion to the current collector, reduces the spread of heat on the negative electrode sheet, reduces the spread of thermal runaway in the battery cell, and improves the reliability of the battery cell.

[0048] In some embodiments, the elastic modulus of the substrate layer is greater than the elastic modulus of the isolation film.

[0049] In the above technical solution, the elastic modulus of the substrate layer is greater than the elastic modulus of the isolation membrane. When the positive electrode sheet and the negative electrode sheet are short-circuited, the cross-sectional area of ​​the through hole can be made large enough to ensure that the positive electrode sheet and the negative electrode sheet are disconnected, thereby reducing the risk of short circuit between the positive electrode sheet and the negative electrode sheet, reducing the risk of heat diffusion to the current collector, reducing the spread of heat on the current collector, reducing the spread of thermal runaway in the battery cell, and further improving the reliability of the battery cell.

[0050] In some embodiments, the elastic modulus of the substrate layer is B, the elastic modulus of the isolation film is B1, and the relationship is satisfied: 0.8≤B / B1≤5.

[0051] In the above technical solution, by setting 0.8≤B / B1≤5, the substrate layer can have appropriate shrinkage, which is conducive to the shrinkage and fracture of the substrate layer after the battery cell short-circuit generates heat. In addition, the shrinkage of the isolation membrane is reduced, so that the isolation membrane can be reliably arranged between the positive electrode sheet and the negative electrode sheet. The isolation membrane separates the positive electrode sheet and the negative electrode sheet, thereby reducing the risk of short circuit between the positive electrode sheet and the negative electrode sheet.

[0052] In some embodiments, the battery cells are sodium metal battery cells.

[0053] In the above technical solution, sodium metal batteries can charge and discharge quickly, which can improve the performance of battery cells. Moreover, due to the extremely abundant sodium reserves and low cost, setting the battery cells as sodium metal batteries can reduce the production cost of battery cells. At the same time, sodium metal batteries have high rate performance and can fully meet the requirements of use in all climate conditions.

[0054] In a third aspect, an embodiment of the present application provides a battery comprising the above-mentioned battery cell.

[0055] In a fourth aspect, an embodiment of the present application provides an electrical device comprising the above-mentioned battery, which is used to provide electrical energy.

[0056] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] FIG1 is a schematic diagram of a vehicle according to an embodiment of the present application;

[0058] FIG2 is a schematic diagram of a battery according to an embodiment of the present application;

[0059] FIG3 is a schematic diagram of a battery cell according to an embodiment of the present application;

[0060] 4 is a schematic diagram of a current collector having a conductive layer provided with a first insulating layer according to the first embodiment of the present application;

[0061] FIG5 is a schematic diagram of a through-hole formed in a current collector under heating according to the first embodiment of the present application;

[0062] FIG6 is a schematic diagram of a grid area formed on the surface of the conductive layer of the current collector according to the first embodiment of the present application;

[0063] 7 is a schematic diagram of a current collector substrate layer provided with a separator according to a second embodiment of the present application;

[0064] FIG8 is a schematic diagram of a through-hole formed in a current collector under heating according to the second embodiment of the present application;

[0065] FIG9 is a schematic diagram of an electrode assembly formed by winding a positive electrode sheet, a negative electrode sheet, and a separator according to an embodiment of the present application;

[0066] FIG10 is a schematic diagram of an electrode assembly formed by stacking a positive electrode sheet, a negative electrode sheet, and a separator according to an embodiment of the present application. DETAILED DESCRIPTION

[0067] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0068] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0069] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0070] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0071] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0072] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0073] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0074] The term "plurality" used in this application refers to two or more (including two).

[0075] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0076] In the present application, the battery cell can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited to this.

[0077] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0078] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0079] In some embodiments, the negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector. In some embodiments, the negative electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. When a metal foam is used as the negative electrode sheet, the surface of the metal foam may or may not be provided with a negative electrode active material.

[0080] As an example, the negative electrode current collector may be filled with or / and deposited with a lithium source material, potassium metal, or sodium metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0081] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0082] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. 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, without particular limitation. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0083] In this application, the battery cell can be cylindrical, flat, rectangular or other shapes, and the embodiments of this application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of this application do not limit this.

[0084] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing for enclosing one or more battery cells or multiple battery modules. The casing may include an upper casing and a lower casing. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0085] New energy vehicles have experienced rapid growth in recent years. Within the electric vehicle sector, power batteries, as the power source, play an irreplaceable and important role. A battery consists of a housing and multiple cells housed within it. As a core component in new energy vehicles, batteries have high requirements for both safety and cycle life.

[0086] In general power batteries, during the battery charging process, dendrites are deposited on the surface of the electrode. After the dendrites pierce the isolation membrane, they connect the negative electrode and the positive electrode, causing a short circuit in the battery cell, which can easily cause thermal runaway in the battery cell and reduce the reliability of the battery cell.

[0087] Based on the above considerations, in order to solve the problem that dendrites deposited on the surface of the electrode cause short circuits in the battery cells and thermal runaway in the battery cells, the inventors have designed a current collector after in-depth research. The current collector can be a current collector for the positive electrode sheet, a current collector can also be a current collector for the negative electrode sheet, or a current collector can also be a negative electrode sheet. This application uses the current collector as an example for explanation. In the embodiments of this application, the negative electrode sheet is not provided with an active material layer. In this application, by setting the melting point of the substrate layer to be lower than the melting point of the conductive layer, during the battery charging process, the dendrites formed on the current collector pierce the isolation membrane, causing the battery cells to short-circuit and generate heat. When heated, the substrate layer shrinks and breaks, causing the conductive layer to break to form a through hole, thereby reducing the risk of heat diffusion to the current collector, reducing the risk of thermal runaway in the battery cells, and improving the reliability of the battery cells.

[0088] The batteries disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery thermal management system disclosed in this application and batteries can be used to form such electrical devices. This helps expand the scope of application of the battery thermal management system and reduces the difficulty of assembling the battery thermal management system.

[0089] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0090] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0091] Please refer to Figure 1, which is a schematic diagram of the structure of the vehicle provided in some embodiments of the present application. The vehicle 400 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 300 is provided inside the vehicle 400. The battery 300 can be provided at the bottom, head or tail of the vehicle 400. The battery 300 can be used to power the vehicle 400. For example, the battery 300 can be used as an operating power source for the vehicle 1000 and for the circuit system of the vehicle 400, such as for the working power requirements of the vehicle 400 during startup, navigation and operation.

[0092] The vehicle 400 may further include a controller 401 and a motor 402 . The controller 401 is used to control the battery 300 to supply power to the motor 402 , for example, to meet the power requirements of the vehicle 400 during startup, navigation, and driving.

[0093] In some embodiments of the present application, the battery 300 can serve not only as an operating power source for the vehicle 400 , but also as a driving power source for the vehicle 400 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 400 .

[0094] Please refer to Figure 2, which is an exploded view of a battery 300 provided in some embodiments of the present application. The battery 300 includes a housing 301 and a battery cell 200, and the battery cell 200 is accommodated in the housing 301. The housing 301 is used to provide a storage space for the battery cell 200, and the housing 301 can adopt a variety of structures. In some embodiments, the housing 301 may include a first portion 11 and a second portion 12, and the first portion 11 and the second portion 12 cover each other, and the first portion 11 and the second portion 12 jointly define a storage space for accommodating the battery cell 200. The second portion 12 may be a hollow structure with one end open, and the first portion 11 may be a plate-like structure, and the first portion 11 covers the open side of the second portion 12, so that the first portion 11 and the second portion 12 jointly define a storage space; the first portion 11 and the second portion 12 may also be hollow structures with one side open, and the open side of the first portion 11 covers the open side of the second portion 12. Of course, the box body 301 formed by the first part 11 and the second part 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0095] In the battery 300, there may be multiple battery cells 200, and the multiple battery cells 200 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 200. The multiple battery cells 200 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 200 may be housed within the housing 301. Of course, the battery 300 may also be a battery module formed by first connecting multiple battery cells 200 in series, in parallel, or in a hybrid connection, and then the multiple battery modules may be connected in series, in parallel, or in a hybrid connection to form an entire battery cell, and then housed within the housing 301. The battery 300 may also include other structures. For example, the battery 300 may also include a busbar, which may be a plurality of electrical connectors for achieving electrical connection between the multiple battery cells 200.

[0096] Please refer to Figure 3, which is a schematic diagram of the exploded structure of a battery cell 200 provided in some embodiments of the present application. A battery cell 200 is the smallest unit that makes up a battery 300. As shown in Figure 3, a battery cell 200 includes an end cap 201, a housing 206, an electrode assembly 202, and other functional components, such as a current collecting member.

[0097] The end cap 201 is a component that covers the opening of the housing 206 to isolate the internal environment of the battery cell 200 from the external environment. The shape of the end cap 201 can be adapted to the shape of the housing 206 to fit the housing 206. Optionally, the end cap 201 can be made of a material with a certain degree of hardness and strength (such as an aluminum alloy). This prevents the end cap 201 from deforming when subjected to compression or collision, thereby enhancing the structural strength and safety of the battery cell 200. Functional components such as electrode terminals 207 can be provided on the end cap 201. The electrode terminals 207 can be used to electrically connect to the electrode assembly 202 to transmit or receive electrical energy from the battery cell 200. In some embodiments, the end cap 201 can also be provided with a pressure relief mechanism to release internal pressure when the internal pressure or temperature of the battery cell 200 reaches a threshold. The end cap 201 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitation on this. In some embodiments, an insulating member may be provided inside the end cap 201 to isolate the electrical connection components in the housing 206 from the end cap 201 to reduce the risk of short circuit.

[0098] The housing 206 is a component that cooperates with the end cap 201 to form the internal environment of the battery cell 200, wherein the formed internal environment can be used to accommodate the electrode assembly 202, electrolyte, and other components. The housing 206 and the end cap 201 can be independent components. An opening can be provided in the housing 206, and the end cap 201 is closed at the opening to form the internal environment of the battery cell 200. Alternatively, the end cap 201 and the housing 206 can be integrated. Specifically, the end cap 201 and the housing 206 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 206 needs to be encapsulated, the end cap 201 is closed to the housing 206. The housing 206 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 206 can be determined based on the specific shape and size of the electrode assembly 202. The shell 206 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0099] The electrode assembly 202 is a component in the battery cell 200 where electrochemical reactions occur. One or more electrode assemblies 202 may be contained in the housing 206. The electrode assembly 202 is mainly formed by winding or stacking a positive electrode sheet 203 and a negative electrode sheet 204, and a separator 205 is usually provided between the positive electrode sheet 203 and the negative electrode sheet 204. The portion of the electrode sheet having active material or used to carry active material constitutes the main body of the electrode assembly 202, and the portion of the electrode sheet that does not have active material or is not used to carry active material each constitutes a tab. The positive electrode tab and the negative electrode tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery 300, ions in the active material shuttle between the positive and negative electrodes, and the tabs connect the electrode terminals 207 to form a current loop.

[0100] In some examples, the tabs of the electrode assembly 202 are located on the upper side of the main body, and the end cap 201 is located above the electrode assembly 202, so that the electrode terminal 207 is located at the upper end of the battery cell 200, and the tabs are connected to the electrode terminal 207. In some examples, the tabs of the electrode assembly 202 are located on the upper side of the main body, and the end cap 206 is located on the right side of the electrode assembly 202, so that the electrode terminal 207 is located on the side of the battery cell 200. The tabs and the electrode terminal 207 are connected by a current collecting member. The current collecting member is bent to connect the tabs on the upper and lower end surfaces of the electrode assembly 202 to the electrode terminal 207 on the side.

[0101] The electrode assembly 202 is the component within the battery cell 200 where the electrochemical reaction occurs. One or more electrode assemblies 202 may be contained within the housing 206. Electrode assembly 202 is primarily composed of a positive electrode sheet 203 and a negative electrode sheet 204, wound or stacked, with a separator typically positioned between the positive and negative electrodes. During the charge and discharge process of the battery cell 200, ions in the active material shuttle between the positive and negative electrodes, forming a current loop.

[0102] The current collector 100 according to an embodiment of the present application is described below with reference to FIG. 1 to FIG. 10 . The following description is made by taking the current collector 100 as the negative electrode sheet 204 of the battery cell 200 as an example.

[0103] As shown in Figures 4-8 , the present application provides a current collector 100 comprising a conductive layer 10 and a substrate layer 20. The conductive layer 10 is configured to output current. The substrate layer 20 is attached to a portion of the conductive layer 10. The substrate layer 20 has a melting point lower than that of the conductive layer 10. The substrate layer 20 is configured to contract and fracture upon heating, causing the conductive layer 10 to fracture, thereby forming through-holes 21.

[0104] The substrate layer 20 is connected to the conductive layer 10. The conductive layer 10 can be disposed on the outer surface of the substrate layer 20, and current is output outward through the conductive layer 10. Because the melting point of the substrate layer 20 is lower than that of the conductive layer 10, when the temperature of the substrate layer 20 reaches a certain temperature, the substrate layer 20 melts and breaks before the conductive layer 10. This allows the substrate layer 20 to shrink and break when heated, causing the conductive layer 10 to break, thereby forming a through-hole 21. The through-hole 21 can reduce the spread of heat in the current collector 100. It should be noted that even when the through-hole 21 is formed in the current collector 100, the current collector 100 can still function normally.

[0105] During the charging process of the battery cell 200, metal ions are deposited on the negative electrode sheet 204 to form dendrites. The dendrites pierce the isolation membrane 205 and connect between the positive electrode sheet 203 and the negative electrode sheet 204, causing a short circuit between the positive electrode sheet 203 and the negative electrode sheet 204. After the short circuit between the positive electrode sheet 203 and the negative electrode sheet 204, heat is generated. The heat is transferred to the current collector 100, and the substrate layer 20 shrinks and breaks when heated. When the substrate layer 20 breaks, the conductive layer 10 breaks to form a through hole 21. For example, after the heat is transferred to the current collector 100, the substrate layer 20 that is connected to the dendrites is broken. The conductive layer 10 breaks at the position opposite to the dendrite due to heat shrinkage, so as to form a through hole 21 on the current collector 100. The through hole 21 penetrates the current collector 100 in the thickness direction of the current collector 100. After the through hole 21 is formed, the positive electrode sheet 203 and the negative electrode sheet 204 are disconnected, so as to prevent the positive electrode sheet 203 and the negative electrode sheet 204 from short-circuiting, reduce the risk of heat diffusion to the current collector 100, reduce the spread of heat on the current collector 100, reduce the spread of thermal runaway of the battery cell 200, and improve the reliability of the battery cell 200.

[0106] The conductive layer 10 is used to conduct current from the electrode and can be made of aluminum or other conductive materials.

[0107] In the above technical solution, by setting the melting point of the substrate layer 20 to be lower than the melting point of the conductive layer 10, during the charging process of the battery cell 200, the dendrites formed on the current collector 100 pierce the isolation membrane 205, causing the battery cell 200 to short-circuit and generate heat. The substrate layer 20 shrinks and breaks when heated, causing the conductive layer 10 to break to form a through hole 21, thereby reducing the risk of heat diffusion to the current collector 100, reducing the risk of thermal runaway of the battery cell 200, and improving the reliability of the battery cell 200.

[0108] In some embodiments, the melting point of the substrate layer 20 is A, which satisfies the relationship: 110° C.≤A≤130° C.

[0109] The melting point of the base material layer 20 may be 110° C., 115° C., 116° C., 120° C., 130° C., and the like.

[0110] In the above technical solution, by setting the melting point of the substrate layer 20 to A, the substrate layer 20 can have a lower melting point. After the battery cell 200 short-circuits and generates heat, the substrate layer 20 can shrink and break, thereby forming a through hole 21 on the current collector 100. Moreover, when the battery cell 200 operates normally, the substrate layer 20 will not break.

[0111] In some embodiments, the elastic modulus of the substrate layer 20 is B, which satisfies the relationship: B≥15 MPa.

[0112] The elastic modulus of the base material layer 20 may be 15 MPa, 20 MPa, 30 MPa, or the like.

[0113] In the above technical solution, by setting the elastic modulus of the substrate layer 20 to B, the substrate layer 20 can have appropriate shrinkage, which is conducive to shrinkage and fracture of the substrate layer 20 after the battery cell 200 short-circuits and generates heat.

[0114] In some embodiments, as shown in FIG7 and FIG8 , the current collector 100 further includes a separator 30 , which is disposed on the substrate layer 20 . The separator 30 is used to separate the substrate layer 20 into multiple regions. The melting point of the separator 30 is higher than that of the substrate layer 20 .

[0115] Among them, the separator 30 can be set on the outer surface of the substrate layer 20, or the separator 30 can be set inside the substrate layer 20, or the separator 30 is set on the outer surface of the substrate layer 20 and inside the substrate layer 20. The separator 30 divides the substrate layer 20 into multiple areas, and the melting point of the separator 30 is higher than that of the substrate layer 20.

[0116] During the charging process of the battery cell 200, metal ions are deposited on the negative electrode sheet 204 to form dendrites. The dendrites pierce the isolation membrane 205 and connect between the positive electrode sheet 203 and the negative electrode sheet 204, causing a short circuit between the positive electrode sheet 203 and the negative electrode sheet 204. After the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited, heat is generated. The heat is transferred to the current collector 100. When the area of ​​the current collector 100 opposite to the dendrite shrinks and breaks when heated, the conductive layer 10 breaks, forming a through hole 21 in the area of ​​the current collector 100 opposite to the dendrite, thereby disconnecting the short-circuited positive and negative electrodes. Furthermore, because the melting point of the separator 30 is higher than that of the substrate layer 20, when heat is transferred to the substrate layer 20, the separator 30 can prevent the heat from diffusing to other areas on the substrate layer 20, and transfer the heat to the position on the substrate layer 20 opposite the dendrite, thereby reducing the heat transfer to other areas on the substrate layer 20. This further reduces the risk of heat diffusing to the current collector 100, further reduces the spread of heat on the current collector 100, and further reduces the spread of thermal runaway in the battery cell 200, further improving the reliability of the battery cell 200. Since the separator 30 is provided on the substrate layer 20, the separator 30 will prevent the further expansion of the through-hole 21. After the through-hole 21 is formed on the current collector 100, it can continue to be used, thereby extending the service life of the current collector 100. It should be noted that the through-hole 21 is not formed in the area of ​​the current collector 100 that is not directly heated. The current collector 100 without the through-hole 21 is intact. Even if the through-hole 21 is formed in some areas of the current collector 100, the current collector 100 can still function normally, thereby extending the service life of the current collector 100.

[0117] In the above technical solution, by setting the separator 30, after the battery cell 200 short-circuits, the heat is transferred to the area on the current collector 100 opposite to the dendrite, forming a through hole 21 on the current collector 100. Since the separator 30 is set on the substrate layer 20, the separator 30 will prevent the through hole 21 from continuing to expand. After the through hole 21 is formed on the current collector 100, it can continue to be used, thereby extending the service life of the current collector 100.

[0118] In some embodiments, the separator 30 is used to divide the substrate layer 20 into grid-like areas.

[0119] There may be multiple separators 30, and the multiple separators 30 are arranged crosswise to divide the substrate layer 20 into a grid-like area. By dividing the substrate layer 20 into a grid-like area by the separators 30, at least one area can be surrounded by the separators 30. During the charging process of the battery cell 200, the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited and generate heat. The heat is transferred to the current collector 100. When the area of ​​the current collector 100 opposite the dendrite is heated, it shrinks and breaks, causing the conductive layer 10 to break, forming a through hole 21 in the area of ​​the current collector 100 opposite the dendrite, disconnecting the positive electrode sheet 203 and the negative electrode sheet 204. Moreover, when heat is transferred to the substrate layer 20, the separator 30 better prevents the heat from diffusing to other areas on the substrate layer 20, so that the heat is transferred to the position on the substrate layer 20 opposite to the dendrite, reducing the heat transferred to other areas on the substrate layer 20, further reducing the risk of heat diffusing to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway of the battery cell 200, and further improving the reliability of the battery cell 200. Moreover, after the heat is transferred to the substrate layer 20 to form a through hole 21 on the current collector 100, the separator 30 will prevent the through hole 21 from continuing to expand. The current collector 100 can continue to be used after the through hole 21 is formed, further extending the service life of the current collector 100.

[0120] In the above technical solution, the substrate layer 20 is divided into grid-like areas by the separator 30. After heat is transferred to the substrate layer 20 to form a through hole 21 on the current collector 100, the separator 30 will prevent the through hole 21 from continuing to expand. After the through hole 21 is formed on the current collector 100, it can continue to be used, further extending the service life of the current collector 100. When heat is transferred to the substrate layer 20, the separator 30 better prevents the heat from diffusing to other areas on the substrate layer 20, and transfers the heat to the position on the substrate layer 20 opposite to the dendrite, reducing the heat transfer to other areas on the substrate layer 20, further reducing the risk of heat diffusion to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway of the battery cell 200, and further improving the reliability of the battery cell 200.

[0121] In some embodiments, the separator 30 is disposed on a surface of the substrate layer 20 and is located between the substrate layer 20 and the conductive layer 10 .

[0122] The separator 30 is provided on the outer surface of the substrate layer 20 and is located between the substrate layer 20 and the conductive layer 10. When heat is transferred from the conductive layer 10 to the substrate layer 20, by locating the separator 30 between the substrate layer 20 and the conductive layer 10, the separator 30 better prevents the heat from diffusing to other areas on the substrate layer 20, and transfers the heat to the position on the substrate layer 20 opposite the dendrite, thereby reducing the heat transfer to other areas on the substrate layer 20, further reducing the risk of heat diffusing to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway in the battery cell 200, and further improving the reliability of the battery cell 200.

[0123] In the above technical solution, by arranging the separator 30 between the substrate layer 20 and the conductive layer 10, when heat is transferred from the conductive layer 10 to the substrate layer 20, the separator 30 better prevents the heat from diffusing to other areas on the substrate layer 20, and transfers the heat to the position on the substrate layer 20 opposite to the dendrite, reducing the heat transfer to other areas on the substrate layer 20, further reducing the risk of heat diffusion to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway of the battery cell 200, and further improving the reliability of the battery cell 200. In addition, after the heat is transferred to the substrate layer 20 to form a through hole 21 on the current collector 100, the separator 30 will prevent the through hole 21 from continuing to expand.

[0124] In some embodiments, the separator 30 is formed as a coating; or the separator 30 is glued to the substrate layer 20 .

[0125] The separator 30 may be coated on the outer surface of the substrate layer 20, thereby forming a separator 30 coating on the outer surface of the substrate layer 20, thereby achieving the effect of assembling the separator 30 on the substrate layer 20. Alternatively, the separator 30 may be adhered to the outer surface of the substrate layer 20, thereby fixing the separator 30 to the outer surface of the substrate layer 20, reducing the risk of separation of the separator 30 from the substrate layer 20.

[0126] In the above technical solution, the separator 30 is coated on the outer surface of the substrate layer 20, thereby forming a separator 30 coating on the outer surface of the substrate layer 20. This allows the separator 30 to be assembled on the substrate layer 20, making assembly of the separator 30 and the substrate layer 20 simple and convenient. The separator 30 is adhered to the substrate layer 20, thereby securing the separator 30 to the outer surface of the substrate layer 20, reducing the risk of separation between the separator 30 and the substrate layer 20.

[0127] In some embodiments, as shown in FIG. 7 and FIG. 8 , the separator 30 is embedded inside the substrate layer 20 .

[0128] The separator 30 is disposed within the substrate layer 20. Multiple separators 30 may be disposed within the substrate layer 20. As shown in FIG8 , the multiple separators 30 are parallel to each other and spaced apart in sequence, dividing the substrate layer 20 into multiple regions. When heat is transferred from the conductive layer 10 to the substrate layer 20, the portion of the substrate layer 20 opposite the dendrite shrinks and fractures when heated. The fracture of the substrate layer 20 also fractures the conductive layer 10, forming the through-hole 21. By embedding the separator 30 within the substrate layer 20, the separator 30 better prevents heat from spreading to other regions of the substrate layer 20, concentrating the heat at the portion of the substrate layer 20 opposite the dendrite, accelerating the contraction of that portion and reducing the risk of heat transfer to other regions of the substrate layer 20. The risk of heat diffusion to the current collector 100 is also reduced, thereby further reducing the spread of heat to the current collector 100, further reducing the spread of thermal runaway in the battery cell 200, and further improving the reliability of the battery cell 200.

[0129] In the above technical solution, by embedding the separator 30 inside the substrate layer 20, the separator 30 better prevents heat from diffusing to other areas on the substrate layer 20, so that the heat is concentrated at the position opposite to the dendrite on the substrate layer 20, thereby accelerating the shrinkage speed of this position and reducing the risk of heat transfer to other areas on the substrate layer 20, further reducing the risk of heat diffusing to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway in the battery cell 200, and further improving the reliability of the battery cell 200.

[0130] In some embodiments, the ratio of the thickness of the separator 30 to the thickness of the substrate layer 20 is C, which satisfies the relationship: 0.8≤C≤1.1.

[0131] The ratio C of the thickness of the separator 30 to the thickness of the substrate layer 20 may be 0.8, 0.9, 1.1, or other values.

[0132] In the above technical solution, by setting the ratio of the thickness of the separator 30 to the thickness of the substrate layer 20 to C, 0.8≤C≤1.1, the proportion of the separator 30 in the current collector 100 can be made appropriate while ensuring the performance of the separator 30.

[0133] In some embodiments, the melting point of the separator 30 is D, satisfying the relationship: 180°≤D.

[0134] The melting point of the separator 30 may be 180°, 190°, 200°, etc. The melting point of the separator 30 may be reasonably selected according to actual usage.

[0135] In the above technical solution, by setting the melting point of the separator 30 to D, it is possible to ensure that the melting point of the separator 30 is higher than the melting point of the substrate layer 20. After a short circuit occurs in the battery cell 200, heat is transferred to the area on the current collector 100 opposite to the dendrite, forming a through hole 21 on the current collector 100. Since the melting point of the separator 30 is higher than the melting point of the substrate layer 20, the risk of the separator 30 melting can be reduced.

[0136] In some embodiments, the separator 30 is a polyimide member.

[0137] Among them, polyimide parts are resistant to high temperatures of more than 400°C, have high insulation properties, and are low in cost.

[0138] In the above technical solution, by setting the separator 30 as a polyimide member, it is not easy to break when heated, so that the separator 30 can have reliable working performance and the production cost of the current collector 100 can also be reduced.

[0139] In some embodiments, the conductive layer 10 completely wraps around the outer peripheral wall of the substrate layer 20 .

[0140] The outer peripheral wall of the substrate layer 20 refers to the outer surface of the substrate layer 20, and the conductive layer 10 is provided on the entire outer peripheral wall of the substrate layer 20. By completely wrapping the conductive layer 10 around the outer peripheral wall of the substrate layer 20, the installation area of ​​the conductive layer 10 can be increased, thereby improving the output current capacity of the current collector 100.

[0141] In the above technical solution, by completely wrapping the conductive layer 10 around the outer peripheral wall of the substrate layer 20 , the installation area of ​​the conductive layer 10 can be increased, and the output current capacity of the current collector 100 can be improved.

[0142] In some embodiments, the conductive layer 10 is a metal coating disposed on the substrate layer 20 ; or the conductive layer 10 is adhered to the substrate layer 20 .

[0143] The conductive layer 10 can be coated on the outer surface of the substrate layer 20, thereby forming a conductive layer 10 coating on the outer surface of the substrate layer 20, thereby achieving the effect of assembling the conductive layer 10 on the substrate layer 20. Alternatively, the conductive layer 10 can be adhered to the outer surface of the substrate layer 20 by gluing, thereby fixing the conductive layer 10 to the outer surface of the substrate layer 20, reducing the risk of separation of the conductive layer 10 from the substrate layer 20.

[0144] In the above technical solution, the conductive layer 10 is coated on the outer surface of the substrate layer 20, thereby forming a conductive layer 10 coating on the outer surface of the substrate layer 20, thereby achieving the effect of assembling the conductive layer 10 on the substrate layer 20, making the assembly of the separator 30 and the substrate layer 20 simple and convenient. By adhering the conductive layer 10 to the substrate layer 20, the conductive layer 10 is fixed to the outer surface of the substrate layer 20, reducing the risk of separation of the conductive layer 10 and the substrate layer 20.

[0145] In some embodiments, as shown in Figures 4 and 5, the current collector 100 also includes a first insulating layer 40, which is disposed on the first surface of the conductive layer 10 facing away from the substrate layer 20. The first insulating layer 40 is used to divide the first surface into multiple regions, and the melting point of the first insulating layer 40 is higher than that of the conductive layer 10.

[0146] As shown in Figure 4, the first insulating layer 40 has insulating and heat-insulating functions. The surface of the conductive layer 10 opposite to the isolation film 205 is the first surface of the conductive layer 10 facing away from the substrate layer 20. The first insulating layer 40 is arranged on the first surface. The first insulating layer 40 can be adhered to the first surface. The first insulating layer 40 can also be coated on the first surface. There can be multiple first insulating layers 40, and multiple first insulating layers 40 are all arranged on the first surface. The first surface is divided into multiple areas by the first insulating layer 40.

[0147] During the charging process of the battery cell 200, metal ions are deposited on the negative electrode sheet 204 to form dendrites. The dendrites pierce the isolation membrane 205 and connect between the positive electrode sheet 203 and the negative electrode sheet 204, causing a short circuit between the positive electrode sheet 203 and the negative electrode sheet 204. After the short circuit between the positive electrode sheet 203 and the negative electrode sheet 204, heat is generated. The heat is transferred to the current collector 100. When the area of ​​the current collector 100 opposite the dendrites shrinks and breaks when heated, causing the conductive layer 10 to break, thereby forming a through hole 21 in the area of ​​the current collector 100 opposite the dendrites, disconnecting the positive electrode sheet 203 and the negative electrode sheet 204. Furthermore, because the melting point of the first insulating layer 40 is higher than that of the conductive layer 10, when heat is transferred to the substrate layer 20, the first insulating layer 40 is prevented from breaking. The first insulating layer 40 can prevent the heat from diffusing to other areas on the substrate layer 20, and transfers the heat to the position on the substrate layer 20 opposite the dendrites, thereby reducing the heat transfer to other areas on the substrate layer 20. This further reduces the risk of heat diffusing to the current collector 100, further reduces the spread of heat on the current collector 100, and further reduces the spread of thermal runaway in the battery cell 200, thereby further improving the reliability of the battery cell 200. At the same time, because the first insulating layer 40 is insulating, if the first insulating layer 40 contacts the positive electrode sheet 203, the first insulating layer 40 is prevented from connecting the positive electrode sheet 203 and the negative electrode sheet 204, thereby preventing the positive electrode sheet 203 and the negative electrode sheet 204 from short-circuiting.

[0148] In the above technical solution, by setting the first insulating layer 40, the first insulating layer 40 divides the first surface into multiple areas. The first insulating layer 40 can reduce the diffusion of heat to other areas on the substrate layer 20, and transfer the heat to the position opposite to the dendrite on the substrate layer 20, while further reducing the risk of heat diffusion to the current collector 100, thereby reducing the spread of thermal runaway in the battery cell 200 and improving the reliability of the battery cell 200.

[0149] In some embodiments, as shown in FIG. 6 , the first insulating layer 40 includes a plurality of intersecting insulating strips 41 to define a grid-like region.

[0150] As shown in FIG. 7 , the first insulating layer 40 includes a plurality of intersecting insulating strips 41 , and the plurality of insulating strips 41 are cross-arranged to define a grid-like area on the first surface.

[0151] A grid-like area is defined on the first surface by a plurality of insulating strips 41, so that at least one area is surrounded by the insulating strips 41. During the charging process of the battery cell 200, dendrites form in a certain area between the insulating strips 41. The positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited and generate heat. The heat is transferred to the current collector 100. When heated, the area of ​​the current collector 100 opposite the dendrite shrinks and fractures, causing the conductive layer 10 to fracture, forming a through hole 21 in the area of ​​the current collector 100 opposite the dendrite, disconnecting the positive electrode sheet 203 and the negative electrode sheet 204. Moreover, when heat is transferred to the conductive layer 10, the insulating strip 41 better prevents the heat from diffusing to other areas on the conductive layer 10, so that the heat is transferred to the position on the conductive layer 10 opposite to the dendrite, and thus the heat is transferred to the position on the substrate layer 20 opposite to the dendrite, reducing the heat transferred to other areas on the substrate layer 20, further reducing the risk of heat diffusing to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway in the battery cell 20, and further improving the reliability of the battery cell 200.

[0152] In the above technical solution, a grid-like area is defined on the first surface by multiple insulating strips 41. When heat is transferred to the conductive layer 10, the insulating strips 41 better prevent the heat from diffusing to other areas on the conductive layer 10, so that the heat is transferred to the position on the conductive layer 10 opposite to the dendrites, and thus the heat is transferred to the position on the substrate layer 20 opposite to the dendrites, reducing the heat transferred to other areas on the substrate layer 20, further reducing the risk of heat diffusion to the current collector 100, further reducing the spread of heat on the current collector 100, further reducing the spread of thermal runaway in the battery cell 20, and further improving the reliability of the battery cell 200.

[0153] In some embodiments, the first insulating layer 40 is formed as a coating; or the first insulating layer 40 is adhered to the conductive layer 10 .

[0154] The first insulating layer 40 can be coated on the first surface of the conductive layer 10, thereby forming a first insulating layer 40 coating on the first surface, thereby achieving the effect of assembling the first insulating layer 40 on the conductive layer 10. Alternatively, the first insulating layer 40 can be adhered to the outer surface of the conductive layer 10 by gluing, thereby fixing the first insulating layer 40 to the outer surface of the conductive layer 10, reducing the risk of separation between the conductive layer 10 and the first insulating layer 40.

[0155] In the above technical solution, the first insulating layer 40 is coated on the first surface of the conductive layer 10, thereby forming a first insulating layer 40 coating on the first surface. This achieves the effect of assembling the first insulating layer 40 on the conductive layer 10, making the assembly of the first insulating layer 40 and the conductive layer 10 simple and convenient. The first insulating layer 40 is adhered to the conductive layer 10, thereby fixing the first insulating layer 40 to the outer surface of the conductive layer 10, reducing the risk of separation between the conductive layer 10 and the first insulating layer 40.

[0156] As shown in FIG3 , FIG4 and FIG7 , the present application further provides a battery cell 200 , including: a positive electrode sheet 203 and a negative electrode sheet 204 , at least one of the positive electrode sheet 203 and the negative electrode sheet 204 includes the current collector 100 of the above embodiment.

[0157] At least one of the positive electrode sheet 203 and the negative electrode sheet 204 includes the current collector 100 of the above embodiment. During the charging process of the battery cell 200, when the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited, the positive electrode sheet 203 and the negative electrode sheet 204 generate heat after the short circuit, and the heat is transferred to the current collector 100. The substrate layer 20 shrinks and breaks when heated, and when the substrate layer 20 breaks, the conductive layer 10 breaks to form a through hole 21. For example: after the heat is transferred to the current collector 100, the position of the substrate layer 20 opposite to the dendrite shrinks and breaks due to the heat, causing the conductive layer 10 to break at the position opposite to the dendrite to form a through hole 21 on the current collector 100, disconnecting the short circuit connection between the positive electrode sheet 203 and the negative electrode sheet 204. The through hole 21 penetrates the current collector 100 in the thickness direction of the current collector 100 , reducing the risk of heat diffusion to the current collector 100 , reducing the spread of heat on the current collector 100 , reducing the spread of thermal runaway of the battery cell 200 , and improving the reliability of the battery cell 200 .

[0158] In some embodiments, as shown in FIG. 4 and FIG. 7 , the negative electrode sheet 204 is provided with a current collector 100 .

[0159] In this embodiment, the negative electrode sheet 204 is provided with a current collector 100 , and the positive electrode sheet 203 may be provided with the current collector 100 of the above embodiment, or may not be provided with the current collector 100 of the above embodiment.

[0160] During the charging process of the battery cell 200, metal ions are deposited on the negative electrode sheet 204 to form dendrites. These dendrites pierce the separator 205 and connect between the positive electrode sheet 203 and the negative electrode sheet 204, causing a short circuit between the positive electrode sheet 203 and the negative electrode sheet 204. This short circuit generates heat, which is transferred to the negative electrode sheet 204. The substrate layer 20 contracts and breaks when heated. The fracture of the substrate layer 20 also causes the conductive layer 10 to break, forming a through hole 21. After the through hole 21 is formed, the positive electrode sheet 203 and the negative electrode sheet 204 are disconnected. This reduces the risk of heat diffusion to the current collector 100, reduces the spread of heat to the negative electrode sheet 204, and reduces the spread of thermal runaway in the battery cell 200, thereby improving the reliability of the battery cell 200.

[0161] In the above technical solution, a current collector 100 is provided through the negative electrode sheet 204. During the charging process of the battery cell 200, after the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited, heat is transferred to the negative electrode sheet 204, and a through hole 21 is formed in the negative electrode sheet 204, thereby reducing the risk of heat diffusion to the current collector 100, reducing the spread of heat on the negative electrode sheet 204, reducing the spread of thermal runaway in the battery cell 200, and improving the reliability of the battery cell 200.

[0162] In some embodiments, a separator 205 is provided between the positive electrode sheet 203 and the negative electrode sheet 204 , and the elastic modulus of the substrate layer 20 is greater than the elastic modulus of the separator 205 .

[0163] Among them, the positive electrode sheet 203, the negative electrode sheet 204 and the isolation film 205 form the electrode assembly 202. As shown in Figure 9, the positive electrode sheet 203, the negative electrode sheet 204 and the isolation film 205 are wound to form the electrode assembly 202. As shown in Figure 10, the positive electrode sheet 203, the negative electrode sheet 204 and the isolation film 205 are stacked to form the electrode assembly 202.

[0164] If the elastic modulus of the substrate layer 20 is smaller than the elastic modulus of the separator 205 , after the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited, heat is transferred to the current collector 100 , and the cross-sectional area of ​​the through hole 21 formed on the substrate layer 20 is small, and it is impossible to ensure that the positive electrode sheet 203 and the negative electrode sheet 204 are disconnected. In the present application, the dendrites pierce the isolation membrane 205, and the dendrites are connected between the positive electrode sheet 203 and the negative electrode sheet 204, causing a short circuit between the positive electrode sheet 203 and the negative electrode sheet 204. After the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited, heat is generated, and the heat is transferred to the current collector 100. The substrate layer 20 shrinks and breaks when heated, and when the substrate layer 20 breaks, the conductive layer 10 breaks to form a through hole 21. By making the elastic modulus of the substrate layer 20 greater than the elastic modulus of the isolation membrane 205, the cross-sectional area of ​​the through hole 21 can be made large enough to ensure that the positive electrode sheet 203 and the negative electrode sheet 204 are disconnected, reducing the risk of short circuit between the positive electrode sheet 203 and the negative electrode sheet 204, reducing the risk of heat diffusion to the current collector 100, reducing the spread of heat on the current collector 100, reducing the spread of thermal runaway of the battery cell 200, and improving the reliability of the battery cell 200.

[0165] In the above technical solution, by making the elastic modulus of the substrate layer 20 greater than the elastic modulus of the isolation membrane 205, when the positive electrode sheet 203 and the negative electrode sheet 204 are short-circuited, the cross-sectional area of ​​the through hole 21 can be made large enough to ensure that the positive electrode sheet 203 and the negative electrode sheet 204 are disconnected, thereby reducing the risk of short circuit between the positive electrode sheet 203 and the negative electrode sheet 204, reducing the risk of heat diffusion to the current collector 100, reducing the spread of heat on the current collector 100, reducing the spread of thermal runaway in the battery cell 200, and further improving the reliability of the battery cell 200.

[0166] In some embodiments, the elastic modulus of the substrate layer 20 is B, and the elastic modulus of the isolation film 205 is B1, satisfying the relationship: 0.8≤B / B1≤5.

[0167] Among them, B / B1 can be a value such as 0.8, 0.9, 5, etc. The ratio of B / B1 can be reasonably selected and set according to actual usage requirements.

[0168] In the above technical solution, by setting 0.8≤B / B1≤5, the substrate layer 20 can have appropriate shrinkage. After the battery cell 200 short-circuits and generates heat, it is beneficial for the substrate layer 20 to shrink and break. In addition, the shrinkage of the isolation film 205 is reduced, so that the isolation film 205 can be reliably set between the positive electrode sheet 203 and the negative electrode sheet 204. The isolation film 205 separates the positive electrode sheet 203 and the negative electrode sheet 204, thereby reducing the risk of short circuit between the positive electrode sheet 203 and the negative electrode sheet 204.

[0169] In some embodiments, the battery cell 200 is a sodium metal battery cell 200 .

[0170] The sodium metal battery cells 200 can be quickly charged and discharged, which can improve the performance of the battery cells 200. Furthermore, due to the abundant sodium reserves and low cost, using the sodium metal battery cells 200 can reduce the production cost of the battery cells 200. Furthermore, the sodium metal battery cells 200 have high rate performance, fully meeting the requirements for use in all climate conditions.

[0171] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0172] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, 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 any one or more embodiments or examples.

[0173] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A current collector, characterized in that: include: A conductive layer for outputting current; a substrate layer attached to a portion of the conductive layer, The melting point of the base material layer is lower than the melting point of the conductive layer, and the base material layer is configured to shrink and break when heated, causing the conductive layer to break to form a through hole.

2. The current collector according to claim 1, characterized in that The melting point of the substrate layer is A, which satisfies the relationship: 110°C≤A≤130°C.

3. The current collector according to claim 1, characterized in that The elastic modulus of the substrate layer is B, which satisfies the relationship: B≥15 MPa.

4. The current collector according to any one of claims 1 to 3, characterized in that The invention further comprises a separator, which is provided on the substrate layer and is used to separate the substrate layer into a plurality of regions. The melting point of the separator is higher than that of the substrate layer.

5. The current collector according to claim 4, characterized in that The separator is used to divide the substrate layer into grid-shaped areas.

6. The current collector according to claim 4 or 5, characterized in that: The separator is provided on the surface of the base material layer and is located between the base material layer and the conductive layer.

7. The current collector according to claim 6, characterized in that The separator is formed as a coating; or The separator is adhered to the substrate layer.

8. The current collector according to claim 4, characterized in that The separator is embedded in the base material layer.

9. The current collector according to claim 8, characterized in that The ratio of the thickness of the separator to the thickness of the substrate layer is C, which satisfies the relationship: 0.8≤C≤1.

1.

10. The current collector according to any one of claims 4 to 9, characterized in that: The melting point of the separator is D, which satisfies the relationship: 180°≤D.

11. The current collector according to any one of claims 4 to 9, characterized in that: The separator is a polyimide member.

12. The current collector according to any one of claims 1 to 11, characterized in that The conductive layer completely wraps around the outer peripheral wall of the substrate layer.

13. The current collector according to claim 1, characterized in that The conductive layer is a metal coating provided on the substrate layer; or The conductive layer is adhered to the base material layer.

14. The current collector according to any one of claims 1 to 13, characterized in that It also includes a first insulating layer, which is arranged on the first surface of the conductive layer away from the substrate layer. The first insulating layer is used to divide the first surface into multiple areas, and the melting point of the first insulating layer is higher than that of the conductive layer.

15. The current collector according to claim 14, characterized in that: The first insulating layer includes a plurality of intersecting insulating strips to define a grid-like area.

16. The current collector according to claim 15, characterized in that The first insulating layer is formed as a coating; or The first insulating layer is adhered to the conductive layer.

17. A battery cell, characterized in that: include: A positive electrode sheet and a negative electrode sheet, at least one of the positive electrode sheet and the negative electrode sheet comprises a current collector according to any one of claims 1 to 16.

18. The battery cell according to claim 17, characterized in that The negative electrode sheet is provided with the current collector.

19. The battery cell according to claim 17 or 18, characterized in that: A separator is provided between the positive electrode sheet and the negative electrode sheet, and the elastic modulus of the substrate layer is greater than the elastic modulus of the separator.

20. The battery cell according to claim 19, characterized in that The elastic modulus of the substrate layer is B, and the elastic modulus of the isolation membrane is B1, satisfying the relationship: 0.8≤B / B1≤5.

21. The battery cell according to any one of claims 17 to 20, characterized in that: The battery cell is a sodium metal battery cell.

22. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 17 to 21.

23. An electrical device, characterized in that: The battery according to claim 22 is included for providing electrical energy.

Images