Electrode assembly, battery cell, battery and electric device

Abstract

The invention discloses an electrode assembly, a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. Wherein the electrode assembly (30) comprises a positive plate (31), a negative current collector (32) and a supporting layer (33), the positive plate (31) and the negative current collector (32) are arranged along a first direction X, the negative current collector (32) is provided with a first side surface and a second side surface which are opposite in the first direction X, the supporting layer (33) is arranged on the negative current collector (32), and at least part of the first side surface and / or at least part of the second side surface is provided with the supporting layer (33).

Description

Electrode assembly, battery cell, battery and electrical device Technical Field

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

[0002] In the related art, during the charging process of the battery, metal (such as lithium, sodium and potassium) will precipitate / deposit in the negative electrode current collector, causing the volume of the negative electrode to expand. At the same time, the metal deposition thickness uniformity at different positions of the negative electrode current collector is poor, causing irregular expansion of the negative electrode current collector. The electrode assembly is deformed under the action of uneven expansion force, causing the tab to be easily locally pulled and damaged, causing battery safety accidents, and poor battery safety and reliability.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide an electrode assembly, a battery cell, a battery, and an electrical device, which can prevent cracks and breakages in the tabs.

[0005] In a first aspect, an embodiment of the present application provides an electrode assembly, comprising: a positive electrode sheet, a negative electrode current collector, and a support layer, wherein the positive electrode sheet and the negative electrode current collector are arranged along a first direction, and the negative electrode current collector has a first side surface and a second side surface relative to each other in the first direction; the support layer is provided on the negative electrode current collector, and at least a portion of the first side surface and / or at least a portion of the second side surface is provided with the support layer.

[0006] In the above technical solution, a support layer is provided on at least a portion of the first side surface and / or at least a portion of the second side surface of the negative electrode current collector. The support layer can limit the uneven growth of metal deposition on the negative electrode electrode sheet, reduce the irregular expansion of the negative electrode electrode sheet during the charging process, thereby reducing the pulling on the electrode tab, thereby avoiding cracks and breakage of the electrode tab, and improving the safety and reliability of the battery cell.

[0007] In some embodiments, the support layer includes: a first support layer and a second support layer, and the first support layer and the second support layer are respectively arranged on the first side surface and the second side surface.

[0008] In the above technical solution, the first support layer and the second support layer are respectively arranged on the first side and the second side, so that the two sides of the negative electrode current collector in the first direction remain flat during the charging process, avoiding uneven expansion of the negative electrode current collector in the first direction, reducing the force on the tab, and improving the safety and reliability of the battery cell.

[0009] In some embodiments, the support layer is disposed on the outside of the negative electrode current collector.

[0010] In the above technical solution, the support layer is arranged on the outside of the negative electrode current collector. During charging, the negative electrode current collector deposits metal ions and increases in volume. The support layer can limit the uneven growth of metal deposition on the negative electrode electrode sheet on the outside of the negative electrode current collector, thereby avoiding uneven expansion of the negative electrode current collector.

[0011] In some embodiments, the support layer further includes: a connecting support layer, the negative electrode current collector further has an outer peripheral surface connected between the first side surface and the second side surface, the connecting support layer is arranged on the outer peripheral surface, and the connecting support layer is connected between the first support layer and the second support layer.

[0012] In the above technical solution, the support layer can be arranged on the circumferential outer side of the negative electrode current collector. During charging, the support layer can limit the uneven growth of metal deposition on the negative electrode plate on the circumferential side of the negative electrode current collector, thereby avoiding uneven expansion of the negative electrode current collector in the circumferential direction.

[0013] In some embodiments, the first supporting layer, the second supporting layer and the connecting supporting layer are integrally formed.

[0014] In the above technical solution, the support layer can be integrally formed to facilitate the production of the support layer. At the same time, the integrally formed support layer can also ensure the consistency of the performance of the support layer in all directions to avoid uneven expansion of the negative electrode current collector.

[0015] In some embodiments, in the first direction, the orthographic projection area of ​​the support layer is greater than or equal to the orthographic projection area of ​​the positive electrode sheet.

[0016] In the above technical solution, the support layer can separate the positive electrode sheet from the negative electrode current collector. During charging, the volume of the negative electrode current collector increases. In the process of the negative electrode current collector expanding the support layer, since S1 ≥ S2, it can be ensured that when the support layer expands outward and squeezes the positive electrode sheet, the entire positive electrode sheet is squeezed by the support layer, avoiding partial force on the positive electrode sheet to cause tilting and large movement, which is beneficial to improving the stability of the positive electrode sheet.

[0017] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode sheet and the negative electrode current collector to separate the positive electrode sheet and the negative electrode current collector.

[0018] In the above technical solution, the diaphragm can prevent the positive electrode sheet from short-circuiting with the negative electrode current collector, and enable the electrode assembly to form a charge and discharge circuit, thereby ensuring the charge and discharge function of the electrode assembly.

[0019] In some embodiments, the diaphragm is integrally formed with the adjacent support layer.

[0020] In the above technical solution, the integrally formed diaphragm and support layer can reduce the number of parts of the electrode assembly and facilitate the production of the electrode assembly.

[0021] In some embodiments, the support layer and the diaphragm are made of the same material.

[0022] In the above technical solution, the support layer and the diaphragm are made of the same material to ensure that the electrode assembly can realize the charge and discharge functions, avoid short circuit of the electrode assembly, and improve the safety of the electrode assembly.

[0023] In some embodiments, the support layer has a strength greater than or equal to that of the diaphragm.

[0024] In the above technical solution, the strength of the support layer is greater than or equal to the strength of the diaphragm, which avoids the support layer from breaking and failing, and improves the safety and reliability of the electrode assembly.

[0025] In some embodiments, the support layer is made of a polymer.

[0026] In the above technical solution, the high molecular polymer support layer has good strength, heat resistance, corrosion resistance, and electrical insulation to meet the use requirements of the electrode assembly.

[0027] In some embodiments, the initial thickness a of the support layer and the thickness b of the negative electrode current collector in a fully charged state satisfy the relationship: 1%≤a / b≤50%.

[0028] In the above technical solution, the initial thickness a of the support layer and the thickness b of the negative electrode current collector in the fully charged state satisfy the relationship: 1%≤a / b≤50%, so as to reduce the impact of the support layer on the capacity of the battery cell while ensuring the reliability of the support layer.

[0029] In some embodiments, the initial thickness a of the support layer and the thickness b of the negative electrode current collector in a fully charged state further satisfy the relationship: 2%≤a / b≤40%.

[0030] In the above technical solution, the initial thickness a of the support layer and the thickness b of the negative electrode current collector in the fully charged state satisfy the relationship: 2%≤a / b≤40%, so as to further reduce the impact of the support layer on the capacity of the battery cell while ensuring the reliability of the support layer.

[0031] In some embodiments, the outer surface of the negative electrode current collector has a negative electrode active material layer.

[0032] In the above technical solution, the outer surface of the negative electrode current collector has a negative electrode active material layer, and the active material layer can embed or extract metal ions to enable the electrode assembly to undergo electrochemical reaction.

[0033] In some embodiments, the support layer is elastic.

[0034] In the above technical solution, the support layer is elastic. When charging causes metal deposition on the negative electrode current collector and its volume increases, the support layer is expanded by the negative electrode current collector, and the support layer undergoes elastic deformation and exerts a reaction force on the negative electrode current collector. Moreover, locations with greater metal deposition thickness on the negative electrode current collector are subjected to greater reaction forces from the support layer, while locations with smaller metal deposition thickness on the negative electrode current collector are subjected to smaller reaction forces from the support layer. As a result, under the constraint of the support layer on the negative electrode current collector, the thickness of the metal deposition at different locations on the negative electrode current collector tends to be the same, thereby ensuring that the volume of the negative electrode current collector increases uniformly.

[0035] In some embodiments, the negative electrode current collector has a tab, and the tab has an expansion portion, which is used to provide expansion space for the tab.

[0036] In the above technical solution, the tab has an expandable portion. When the volume of the negative electrode current collector changes, the expandable portion can expand and contract to maintain the electrical connection of the tab, avoiding excessive expansion of the thickness of the electrode assembly, which may cause the tab to be pulled and cracked or even broken, thereby improving the reliability of the battery.

[0037] In some embodiments, the telescopic portion includes at least one curved structure.

[0038] In the above technical solution, the curved structure can realize the folding of the length of the tab, providing additional stretching space for the tab when the volume of the negative electrode collector changes, thereby preventing the tab from being pulled and cracked or even broken due to excessive volume change of the negative electrode collector.

[0039] In some embodiments, the support layer is sleeved on the outside of the negative electrode current collector, and the tab passes through the support layer.

[0040] In the above technical solution, the tabs can conduct the electrical energy of the electrode assembly and supply power to external electrical equipment.

[0041] In a second aspect, an embodiment of the present application provides a battery cell comprising the above-mentioned electrode assembly.

[0042] In a third aspect, an embodiment of the present application provides a battery comprising the above-mentioned battery cell.

[0043] In a fourth aspect, an embodiment of the present application provides an electrical device comprising the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0045] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0046] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0047] FIG3 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0048] FIG4 is a schematic structural diagram of an electrode assembly provided in some embodiments of the present application before charging;

[0049] FIG5 is a schematic structural diagram of an electrode assembly after being fully charged, according to some embodiments of the present application;

[0050] FIG6 is a schematic diagram of a battery cell provided by some embodiments of the present application, wherein the bent structure of the tab is in a contracted state;

[0051] FIG7 is a schematic diagram of a battery cell provided by some embodiments of the present application, wherein the bent structure of the tab is in a stretched state;

[0052] FIG8 is a schematic structural diagram of the telescopic portion of the tab provided in some embodiments of the present application. DETAILED DESCRIPTION

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," and "attached" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0058] 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.

[0059] 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.

[0060] The term "plurality" used in this application refers to two or more (including two).

[0061] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0062] 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 battery pack. A battery generally includes a casing that encloses one or more battery cells or multiple battery modules. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0063] A battery cell consists of a casing, an electrode assembly, and an electrolyte. The casing is used to hold the electrode assembly and electrolyte. The electrode assembly may include a positive electrode sheet, a negative electrode current collector, and a separator. A battery cell primarily operates by the movement of metal ions between the positive electrode sheet and the negative electrode current collector. The positive electrode sheet includes a positive electrode current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector uncoated with the positive active material layer protrudes from the coated positive electrode current collector. The uncoated positive electrode current collector serves as the positive electrode tab. For lithium-ion batteries, for example, the positive electrode current collector may be made of aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode current collector may or may not be coated with a negative electrode active material layer. The negative electrode current collector may be made of copper, and the negative electrode active material may be carbon or silicon. To ensure that high currents can pass without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together.

[0064] The material of the separator may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0065] 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. Batteries consist of a housing and multiple cells housed within it. As core components of new energy vehicles, batteries are subject to stringent requirements in terms of both safety and cycle life.

[0066] The inventors discovered that in general power batteries, during the charging process, metal (such as lithium, sodium and potassium) will precipitate / deposit in the negative electrode current collector, causing the volume of the negative electrode to expand. At the same time, the metal deposition thickness uniformity at different positions of the negative electrode current collector is poor, causing the negative electrode current collector to expand irregularly. The electrode assembly is deformed under the action of uneven expansion force, causing the tab to be easily locally pulled and damaged, causing battery safety accidents, and poor battery safety and reliability.

[0067] Based on the above considerations, in order to solve the problem of irregular expansion of the negative electrode current collector during charging, which leads to damage of the electrode tab and causes battery safety accidents, the inventors have designed an electrode assembly after in-depth research, including: a positive electrode sheet, a negative electrode current collector and a support layer. The positive electrode sheet and the negative electrode current collector are arranged along a first direction. In the first direction, the negative electrode current collector has a first side surface and a second side surface relative to each other. The support layer is provided on the negative electrode current collector, and at least a portion of the first side surface and / or at least a portion of the second side surface is provided with a support layer.

[0068] In an electrode assembly of this structure, the support layer can limit the uneven growth of metal deposition on the negative electrode sheet, reduce the irregular expansion of the negative electrode sheet during charging, reduce the pulling on the tab, and thus avoid cracks and breakage of the tab, thereby improving the safety and reliability of the battery cell.

[0069] 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 electrode assembly and battery disclosed in this application can be used to construct such an electrical device, thereby broadening the scope of application of the electrode assembly and improving the safety and reliability of the battery.

[0070] 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.

[0071] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0072] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 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 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0073] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0074] Please refer to Figure 2, which is an exploded view of the structure of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a plurality of battery cells 20, which are intended to be accommodated within the housing 10. The housing 10 is used to provide an assembly space for the battery cells 20, and the housing 10 can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12, which cover each other and together define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure, with the first housing body 11 covering the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define an assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, with the open side of the first housing body 11 covering the open side of the second housing body 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0075] In the battery 100, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 can be constructed by first connecting the multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then connected in series, in parallel, or in a hybrid configuration to form a single structure and housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0076] Referring to Figure 3 , this application also provides a battery cell 20 . The battery cell 20 includes a housing, an electrode assembly, and an electrolyte. The housing is used to house the electrode assembly and electrolyte. Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be cylindrical, flat, rectangular, or in other shapes. For example, in Figure 3 , the battery cell 20 is in the shape of a rectangular parallelepiped.

[0077] According to some embodiments of the present application, with reference to FIG3 , and further with reference to FIG4 and FIG5 , the present application provides an electrode assembly 30 , which includes: a positive electrode sheet 31 , a negative electrode current collector 32 , and a support layer 33 . The positive electrode sheet 31 and the negative electrode current collector 32 are arranged along a first direction X. In the first direction X, the negative electrode current collector 32 has a first side surface and a second side surface that are opposite to each other. The support layer 33 is provided on the negative electrode current collector 32 , and the support layer 33 is provided on at least a portion of the first side surface and / or at least a portion of the second side surface.

[0078] The positive electrode sheet 31 and the negative electrode current collector 32 may be spaced apart in a first direction X, allowing metal ions to move between the positive electrode sheet 31 and the negative electrode current collector 32 to enable charging and discharging of the battery cell 20. When the battery cell 20 employs a laminated structure, both the first and second sides of the negative electrode current collector 32 may face the positive electrode sheet 31. The support layer 33 may be disposed on the outside of the negative electrode current collector 32. In some examples, the support layer 33 is disposed on at least a portion of the first side of the negative electrode current collector 32. In other examples, the support layer 33 is disposed on at least a portion of the second side of the negative electrode current collector 32. In other examples, the support layer 33 is disposed on at least a portion of the first side of the negative electrode current collector 32 and on at least a portion of the second side. In other words, the support layer 33 fully or partially covers the side surface of the negative electrode current collector 32 in the first direction X, which may be the thickness direction of the negative electrode current collector 32.

[0079] It can be understood that the negative electrode current collector 32 can be used as a negative electrode plate. The negative electrode current collector 32 can be coated with an active material layer and / or have only a primer layer. The main component of the primer layer is at least one of conductive carbon, binder and other substances. The active material layer can be used to enhance the ion transfer rate, and the primer layer can be used to improve the adhesion to facilitate the plate processing. The negative electrode current collector 32 can be coated with only an active material layer, or the negative electrode current collector 32 can have only a primer layer, or the negative electrode current collector 32 can be coated with an active material layer and have a primer layer.

[0080] It should be noted that the support layer 33 allows metal ions to pass through and prevents electrons from passing through to ensure the charge and discharge performance of the electrode assembly 30. At the same time, the support layer 33 has a certain strength and elasticity. During the charging process of the battery cell 20, the volume of the negative electrode current collector 32 increases due to the deposition of metal ions. The support layer 33 can expand in conjunction with the increase in volume of the negative electrode current collector 32. The support layer 33 can limit the uneven growth of metal deposition on the negative electrode electrode sheet, so that the metal ions are evenly deposited on the negative electrode current collector 32, and reduce the thickness difference of the metal deposition on the first side and / or the second side of the negative electrode current collector 32, so that the side of the negative electrode current collector 32 in the first direction X remains flat after the volume increases. Under the condition of the same charging capacity, the inclination and displacement of the negative electrode current collector 32 in the first direction X can be reduced, thereby reducing the displacement of the negative electrode current collector 32 relative to the tab 321 during charging, thereby preventing the tab 321 from being pulled and cracked or even broken.

[0081] In the above technical solution, a support layer 33 is provided on at least a portion of the first side surface and / or at least a portion of the second side surface of the negative electrode current collector 32. The support layer 33 can limit the uneven growth of metal deposition on the negative electrode plate, reduce the irregular expansion of the negative electrode plate during charging, and reduce the pulling on the tab 321, thereby avoiding cracks or even breakage of the tab 321, thereby improving the safety and reliability of the battery cell 20.

[0082] According to some embodiments of the present application, referring to FIG. 4 and FIG. 5 , the support layer 33 includes a first support layer 331 and a second support layer 332 , and the first support layer 331 and the second support layer 332 are respectively provided on the first side surface and the second side surface.

[0083] Among them, the first side and the second side are the two sides of the negative electrode current collector 32 in the first direction X. The first support layer 331 can cover the outer side of the first side. The first support layer 331 can reduce the uneven growth of metal deposition on the first side of the negative electrode current collector 32 and keep the first side flat during the charging process. The second support layer 332 can cover the outer side of the second side. The second support layer 332 can reduce the uneven growth of metal deposition on the second side of the negative electrode current collector 32 and keep the second side flat during the charging process.

[0084] In the above technical solution, the first support layer 331 and the second support layer 332 are respectively arranged on the first side surface and the second side surface, so that the two sides of the negative electrode current collector 32 in the first direction X remain flat during the charging process, thereby avoiding uneven expansion of the negative electrode current collector 32 in the first direction X, reducing the force on the tab 321, and improving the safety and reliability of the battery cell 20.

[0085] According to some embodiments of the present application, referring to FIG. 4 and FIG. 5 , the support layer 33 is sleeved on the outside of the negative electrode current collector 32 .

[0086] The support layer 33 covers the first and second side surfaces of the negative electrode current collector 32 on the outside of the negative electrode current collector 32. In some examples, the support layer 33 is completely wrapped around the outside of the negative electrode current collector 32, that is, any outer side surface of the negative electrode current collector 32 is covered by the support layer 33. In other examples, the support layer 33 is a groove-shaped structure with one end open to facilitate assembly of the support layer 33. In other examples, the support layer 33 is a cylindrical structure with both ends open to facilitate assembly of the support layer 33.

[0087] In the above technical solution, the support layer 33 is arranged on the outside of the negative electrode current collector 32. During charging, the negative electrode current collector 32 deposits metal ions and increases in volume. The support layer 33 can limit the uneven growth of metal deposition on the negative electrode plate on the outside of the negative electrode current collector 32, thereby avoiding uneven expansion of the negative electrode current collector 32.

[0088] According to some embodiments of the present application, the support layer 33 further includes: a connecting support layer, the negative electrode current collector 32 also has an outer peripheral surface connected between the first side surface and the second side surface, the connecting support layer is arranged on the outer peripheral surface, and the connecting support layer is connected between the first support layer 331 and the second support layer 332.

[0089] In which, the outer peripheral surface includes a first sub-peripheral surface and a second sub-peripheral surface, the first side surface and the second side surface are connected at one end perpendicular to the paper surface in Figure 4 through the first sub-peripheral surface, and the first side surface and the second side surface are connected at the other end perpendicular to the paper surface in Figure 4 through the second sub-peripheral surface, the connecting support layer may include a first sub-connecting support layer and a second sub-connecting support layer, one end of the first support layer 331 and the second support layer 332 are connected through the first sub-connecting support layer, and the other end of the first support layer 331 and the second support layer 332 are connected through the second sub-connecting support layer, the first sub-connecting support layer corresponds to the first sub-peripheral surface, and the second sub-connecting support layer corresponds to the second sub-peripheral surface. It can be understood that the first support layer 331, the second support layer 332 and the connecting support layer can be arranged on the circumferential outside of the negative electrode current collector 32.

[0090] In the above technical solution, the support layer 33 can be arranged on the circumferential outer side of the negative electrode current collector 32. During charging, the support layer 33 can limit the uneven growth of metal deposition on the negative electrode plate on the circumferential side of the negative electrode current collector 32, thereby avoiding uneven expansion of the negative electrode current collector 32 in the circumferential direction.

[0091] According to some embodiments of the present application, the first supporting layer 331 , the second supporting layer 332 and the connecting supporting layer are integrally formed.

[0092] Among them, the first support layer 331, the second support layer 332 and the connecting support layer can be made of the same material and manufactured through an integrated molding process to ensure the consistency of the physical properties of the first support layer 331, the second support layer 332 and the connecting support layer, and to make the support layer 33 have the same limiting effect on the metal deposition thickness on each surface of the negative electrode current collector 32, so that during charging, the thickness of the metal deposition on each surface of the negative electrode current collector 32 facing the support layer 33 is the same, ensuring that the volume of the negative electrode current collector 32 increases uniformly.

[0093] In the above technical solution, the support layer 33 can be integrally formed to facilitate the production of the support layer 33 . At the same time, the integrally formed support layer 33 can also ensure the consistency of the performance of the support layer 33 in all directions to avoid uneven expansion of the negative electrode current collector 32 .

[0094] According to some embodiments of the present application, in the first direction X, the orthographic projection area of ​​the support layer 33 is greater than or equal to the orthographic projection area of ​​the positive electrode sheet 31 .

[0095] The projection area S1 of the support layer 33 in the first direction X and the projection area S2 of the positive electrode sheet 31 in the first direction X satisfy the relationship: S1 ≥ S2. It can be understood that the projection of the positive electrode sheet 31 onto the support layer 33 is located inside the support layer 33.

[0096] In the above technical solution, the support layer 33 can separate the positive electrode sheet 31 from the negative electrode current collector 32. During charging, the volume of the negative electrode current collector 32 increases. In the process of the negative electrode current collector 32 expanding the support layer 33, since S1 ≥ S2, it can be ensured that when the support layer 33 expands outward and squeezes the positive electrode sheet 31, the entire positive electrode sheet 31 is squeezed by the support layer 33, avoiding partial force on the positive electrode sheet 31 and causing tilting and large movement, which is beneficial to improving the stability of the positive electrode sheet 31.

[0097] According to some embodiments of the present application, the electrode assembly 30 further includes a separator, which is disposed between the positive electrode sheet 31 and the negative electrode current collector 32 to separate the positive electrode sheet 31 and the negative electrode current collector 32 .

[0098] Among them, the support layer 33 can be arranged on the side of the diaphragm away from the positive electrode sheet 31. The diaphragm can be a semi-permeable membrane with an insulating function. The diaphragm separates the positive electrode sheet 31 and the negative electrode collector 32 to avoid short circuit between the positive electrode sheet 31 and the negative electrode collector 32. Metal ions can pass through the diaphragm to form a charge and discharge circuit.

[0099] In the above technical solution, the separator can prevent the positive electrode sheet 31 and the negative electrode current collector 32 from contacting and short-circuiting, and enables the electrode assembly 30 to form a charge-discharge loop, thereby ensuring the charge-discharge function of the electrode assembly 30.

[0100] According to some embodiments of the present application, the diaphragm and the adjacent support layer 33 are integrally formed.

[0101] The diaphragm and the adjacent support layer 33 can be manufactured through an integral molding process, and the diaphragm and the support layer 33 can be one part after being manufactured and molded.

[0102] In the above technical solution, the integrally formed diaphragm and support layer 33 can reduce the number of parts of the electrode assembly 30 and facilitate the production of the electrode assembly 30 .

[0103] According to some embodiments of the present application, the support layer 33 and the diaphragm are made of the same material.

[0104] The support layer 33 and the diaphragm are made of the same material. Both the support layer 33 and the diaphragm allow metal ions to pass through and prevent electrons from passing through, thereby ensuring that the electrode assembly 30 can achieve charge and discharge functions and preventing the electrode assembly 30 from short-circuiting. It can be understood that the support layer 33 can reduce irregular expansion of the negative electrode sheet during charging, and the diaphragm can improve the safety of the electrode assembly 30. When the support layer 33 is damaged or fails, the diaphragm can prevent the positive electrode sheet 31 and the negative electrode current collector 32 from short-circuiting. Optionally, the support layer 33 and the diaphragm can be made of PP (polypropylene) or PE (polyethylene).

[0105] In the above technical solution, the support layer 33 and the diaphragm are made of the same material to ensure that the electrode assembly 30 can realize the charge and discharge functions, avoid short circuit of the electrode assembly 30, and improve the safety of the electrode assembly 30.

[0106] According to some embodiments of the present application, the strength of the support layer 33 is greater than or equal to the strength of the diaphragm.

[0107] The support layer 33 has a relatively high strength and is less susceptible to damage and failure than the separator, thereby improving the reliability and service life of the support layer 33. It should be noted that the strength can be puncture resistance. When the battery cell 20 is penetrated by external foreign matter, the support layer 33 and the separator can achieve dual short-circuit isolation between the positive electrode sheet 31 and the negative electrode current collector 32. If one of the support layer 33 and the separator fails, the other can still prevent a short circuit between the positive electrode sheet 31 and the negative electrode current collector 32. In addition, during charging, the metal deposits deposited on the negative electrode current collector 32 may form dendrites. If the dendrites pierce the support layer 33 and the diaphragm, a short circuit may occur between the positive electrode sheet 31 and the negative electrode current collector 32. The stronger support layer 33 may prevent the support layer 33 from being pierced by the dendrites, so that the support layer 33 can effectively protect the diaphragm, prevent the dendrites from piercing the diaphragm, and avoid a short circuit between the positive electrode sheet 31 and the negative electrode current collector 32, thereby preventing the battery cell 20 from experiencing thermal runaway.

[0108] In the above technical solution, the strength of the support layer 33 is greater than or equal to the strength of the diaphragm, thereby preventing the support layer 33 from breaking and failing, and improving the safety and reliability of the electrode assembly 30.

[0109] According to some embodiments of the present application, the support layer 33 is made of a high molecular polymer.

[0110] The material of the support layer 33 may be rubber, soft resin, modified PP (polypropylene) or modified PE (polyethylene).

[0111] In the above technical solution, the high molecular polymer support layer 33 has good strength, heat resistance, corrosion resistance, and electrical insulation to meet the use requirements of the electrode assembly 30.

[0112] According to some embodiments of the present application, the initial thickness a of the support layer 33 and the thickness b of the negative electrode current collector 32 in a fully charged state satisfy the relationship: 1%≤a / b≤50%.

[0113] The initial thickness a of the support layer 33 may be the thickness of the support layer 33 when no elastic deformation occurs. When the battery cell 20 is in a fully charged state, the charge level of the battery cell 20 is 100%. At this time, the thickness b of the negative electrode current collector 32 and the initial thickness a of the support layer 33 satisfy the relationship: 1% ≤ a / b ≤ 50%. For example, a / b = 1%, or a / b = 5%, or a / b = 10%, or a / b = 30%, or a / b = 50%. It should be noted that if a / b is less than 1%, the thickness of the support layer 33 is relatively thin, and dendrites generated by the negative electrode current collector 32 during charging can easily pierce the support layer 33, causing failure of the support layer 33. If a / b is greater than 50%, the thickness of the support layer 33 is relatively thick, and the support layer 33 occupies a large space, resulting in a low energy density of the battery cell 20, which affects the capacity of the battery cell 20.

[0114] In the above technical solution, the initial thickness a of the support layer 33 and the thickness b of the negative electrode current collector 32 in the fully charged state satisfy the relationship: 1%≤a / b≤50%, so as to reduce the impact of the support layer 33 on the capacity of the battery cell 20 while ensuring the reliability of the support layer 33.

[0115] According to some embodiments of the present application, the initial thickness a of the support layer 33 and the thickness b of the negative electrode current collector 32 in a fully charged state further satisfy the relationship: 2%≤a / b≤40%.

[0116] Among them, the relationship between the initial thickness a of the support layer 33 and the thickness b of the negative electrode current collector 32 in the fully charged state can be further determined according to design requirements and experiments. The value of a / b can be gradually reduced in the experiment to find the minimum value of a / b that meets the reliability of the support layer 33 to ensure the capacity of the battery cell 20.

[0117] In the above technical solution, the initial thickness a of the support layer 33 and the thickness b of the negative electrode current collector 32 in the fully charged state satisfy the relationship: 2%≤a / b≤40%, so as to further reduce the impact of the support layer 33 on the capacity of the battery cell 20 while ensuring the reliability of the support layer 33.

[0118] According to some embodiments of the present application, the outer surface of the negative electrode current collector 32 has a negative electrode active material layer.

[0119] The negative electrode active material layer can be coated on the surface of the negative electrode current collector 32. The negative electrode current collector 32 not coated with the negative electrode active material layer protrudes from the negative electrode current collector 32 coated with the negative electrode active material layer. The negative electrode current collector 32 not coated with the negative electrode active material layer serves as the negative electrode tab. The negative electrode current collector 32 can be made of copper, and the negative electrode active material can be carbon, silicon, or the like.

[0120] In the above technical solution, the outer surface of the negative electrode current collector 32 has a negative electrode active material layer, and the active material layer can embed or extract metal ions to enable the electrode assembly 30 to perform an electrochemical reaction.

[0121] According to other embodiments of the present application, the outer surface of the negative electrode current collector 32 may not have a negative electrode active material layer, and the negative electrode current collector 32 may include a substrate and a primer layer.

[0122] According to some embodiments of the present application, the support layer 33 is elastic.

[0123] When the battery cell 20 is charged and the volume of the negative electrode collector 32 increases, the support layer 33 cooperates with the negative electrode collector 32 to increase the volume. When the battery cell 20 is discharged and the volume of the negative electrode collector 32 decreases, the support layer 33 cooperates with the negative electrode collector 32 to decrease the volume.

[0124] In the above technical solution, the support layer 33 is elastic. When charging causes metal deposition on the negative electrode current collector 32 and its volume increases, the support layer 33 is expanded by the negative electrode current collector 32, and the support layer 33 is elastically deformed and exerts a reaction force on the negative electrode current collector 32. In addition, locations with thicker metal deposition on the negative electrode current collector 32 are subject to a greater reaction force from the support layer 33, while locations with thinner metal deposition on the negative electrode current collector 32 are subject to a smaller reaction force from the support layer 33. As a result, under the constraint of the support layer 33 on the negative electrode current collector 32, the thickness of the metal deposition at different locations on the negative electrode current collector 32 tends to be the same, ensuring that the volume of the negative electrode current collector 32 increases uniformly.

[0125] According to some embodiments of the present application, as shown in FIG6 and FIG7 , the negative electrode current collector 32 has a tab 321 , and the tab 321 has a telescopic portion 3211 . The telescopic portion 3211 is used to provide a stretching space for the tab 321 .

[0126] Among them, the pole ear 321 can refer to the pole ear on an electrode assembly 30, or it can refer to the pole ears of multiple electrode assemblies 30 that need to be overlapped. The pole ear 321 can be connected to an external electrical device. The pole ear 321 can extract the electrical energy of the electrode assembly 30 and supply power to the external electrical device. The telescopic portion 3211 can be extended and shortened at least in the first direction X, so that when the volume of the negative electrode current collector 32 changes, the force on the pole ear 321 can be reduced by the expansion and contraction of the telescopic portion 3211.

[0127] In the above technical solution, the tab 321 has a telescopic portion 3211. When the volume of the negative electrode current collector 32 changes, the telescopic portion 3211 can be expanded and contracted to maintain the electrical connection of the tab 321, thereby preventing the thickness of the electrode assembly 30 from expanding too much and causing the tab 321 to be pulled and cracked or even broken, thereby improving the reliability of the battery cell 20.

[0128] According to some embodiments of the present application, referring to FIG. 5 and FIG. 6 , the telescopic portion 3211 includes at least one curved structure.

[0129] Among them, the bending structure can realize the folding of the length of the pole ear 321, and provide additional stretching space for the pole ear 321 when the electrode assembly 30 expands. The structure of the bending structure can be at least one of a serrated, arc-shaped, sinusoidal waveform, and a square waveform. The bending structure can have a contracted state and a stretched state. The length of the bent structure in the contracted state is less than its length in the stretched state. The bent structure can move freely during the expansion and contraction of the negative electrode current collector 32, and the force on the pole ear 321 can be reduced by the expansion and contraction of the bent structure.

[0130] Figure 8 shows several different configurations of the telescopic portion 3211. Figure 8 (a) shows a schematic diagram of the telescopic portion 3211 comprising a curved structure. When the electrode assembly 30 expands, a portion of the curved structure arranged along the second direction Y provides additional space for the tab 321 to expand. The second direction Y is perpendicular to the first direction X. Figures 8 (b), (c), and (d) show schematic diagrams of the telescopic portion 3211 comprising multiple curved structures. Figure 8 (b) shows the telescopic portion 3211 formed by interconnected curved segments in the first direction X and the second direction Y, with the curved structure being a square wave. Figure 8 (c) shows the telescopic portion 3211 formed by multiple arc-shaped structures. Figure 8 (d) shows the telescopic portion 3211 formed by interconnected curved segments in the first direction X, with adjacent curved segments forming a certain angle, with the curved structure being a zigzag shape. A curved structure can be considered a cycle of the telescopic portion 3211. The telescopic portion 3211 can be formed by repeating a curved structure multiple times. It should be understood that the present application does not limit the shape of the curved structure.

[0131] The curved structure can achieve the folding of the length of the tab 321, providing additional stretching space for the tab 321 when the electrode assembly 30 expands, preventing the tab 321 from being pulled and cracked or even broken due to excessive thickness expansion of the electrode assembly 30. In the above technical solution, the curved structure can achieve the folding of the length of the tab 321, providing additional stretching space for the tab 321 when the volume of the negative electrode current collector 32 changes, preventing the tab 321 from being pulled and cracked or even broken due to excessive volume change of the negative electrode current collector 32.

[0132] According to some embodiments of the present application, the support layer 33 is sleeved on the outside of the negative electrode current collector 32 , and the tab 321 passes through the support layer 33 .

[0133] The support layer 33 has insulating properties, and one end of the tab 321 can pass through the support layer 33 and be electrically connected to the negative electrode current collector 32 .

[0134] In the above technical solution, the tab 321 can conduct the electrical energy of the electrode assembly 30 and supply power to external electrical equipment.

[0135] According to some embodiments of the present application, the present application further provides a battery cell 20 including the electrode assembly 30 of any of the above solutions.

[0136] According to some embodiments of the present application, the present application further provides a battery 100 including the battery cell 20 of any of the above solutions.

[0137] According to some embodiments of the present application, the present application further provides an electrical device, comprising the battery 100 of any of the above solutions.

[0138] The power-consuming device may be any of the aforementioned devices or systems using the battery 100 .

[0139] According to some embodiments of the present application, referring to Figures 4 to 8, the present application provides an electrode assembly 30, which includes: a positive electrode sheet 31, a negative electrode current collector 32 and a support layer 33. The positive electrode sheet 31 and the negative electrode current collector 32 are arranged along a first direction X. In the first direction X, the negative electrode current collector 32 has a first side surface and a second side surface relative to each other, and an outer peripheral surface connected between the first side surface and the second side surface. The support layer 33 is sleeved on the outside of the negative electrode current collector 32. The support layer 33 includes a first support layer 331, a second support layer 332 and a connecting support layer. The first support layer 331 and the second support layer 332 are respectively arranged on the first side surface and the second side surface, and the connecting support layer is arranged on the outer peripheral surface. The support layer 33 is elastic. The negative electrode current collector 32 has a pole ear 321. The pole ear 321 has a telescopic portion 3211. The telescopic portion 3211 includes at least one curved structure.

[0140] Therefore, by sleeved on the outside of the negative electrode current collector 32, the support layer 33 can be prevented from uneven expansion of the negative electrode current collector 32, and the force on the tab 321 can be reduced. At the same time, when the volume of the negative electrode current collector 32 changes, the expansion portion 3211 of the tab 321 can further reduce the force on the tab 321, thereby preventing the tab 321 from being pulled and damaged, thereby preventing safety accidents.

[0141] 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.

[0142] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An electrode assembly, characterized in that: include: A positive electrode sheet and a negative electrode current collector, the positive electrode sheet and the negative electrode current collector are arranged along a first direction, and the negative electrode current collector has a first side surface and a second side surface opposite to each other in the first direction; A support layer is provided on the negative electrode current collector, and the support layer is provided on at least a portion of the first side surface and / or at least a portion of the second side surface.

2. The electrode assembly according to claim 1, wherein The supporting layer includes: a first supporting layer and a second supporting layer, wherein the first supporting layer and the second supporting layer are respectively arranged on the first side surface and the second side surface.

3. The electrode assembly according to claim 2, characterized in that The support layer is sleeved on the outside of the negative electrode current collector.

4. The electrode assembly according to claim 3, characterized in that The support layer further includes: a connecting support layer. The negative electrode current collector further has an outer peripheral surface connected between the first side surface and the second side surface. The connecting support layer is provided on the outer peripheral surface and connected between the first support layer and the second support layer.

5. The electrode assembly according to claim 4, characterized in that The first supporting layer, the second supporting layer and the connecting supporting layer are integrally formed.

6. The electrode assembly according to claim 4, characterized in that In the first direction, the orthographic projection area of ​​the support layer is greater than or equal to the orthographic projection area of ​​the positive electrode sheet.

7. The electrode assembly according to any one of claims 1 to 6, characterized in that: Also includes: A separator is provided between the positive electrode sheet and the negative electrode current collector to separate the positive electrode sheet and the negative electrode current collector.

8. The electrode assembly according to claim 7, characterized in that The diaphragm is integrally formed with the adjacent support layer.

9. The electrode assembly according to claim 7 or 8, characterized in that: The support layer and the diaphragm are made of the same material.

10. The electrode assembly according to claim 7, characterized in that The strength of the support layer is greater than or equal to the strength of the diaphragm.

11. The electrode assembly according to any one of claims 1 to 10, characterized in that: The material of the support layer is high molecular polymer.

12. The electrode assembly according to any one of claims 1 to 11, characterized in that: The initial thickness a of the support layer and the thickness b of the negative electrode current collector in a fully charged state satisfy the relationship: 1%≤a / b≤50%.

13. The electrode assembly according to claim 12, wherein: The initial thickness a of the support layer and the thickness b of the negative electrode current collector in a fully charged state further satisfy the relationship: 2%≤a / b≤40%.

14. The electrode assembly according to any one of claims 1 to 13, characterized in that: The outer surface of the negative electrode current collector has a negative electrode active material layer.

15. The electrode assembly according to any one of claims 1 to 14, characterized in that: The supporting layer is elastic.

16. The electrode assembly according to any one of claims 1 to 15, characterized in that: The negative electrode current collector has a tab, and the tab has a telescopic portion, and the telescopic portion is used to provide a stretching space for the tab.

17. The electrode assembly according to claim 16, wherein: The telescopic portion includes at least one curved structure.

18. The electrode assembly according to claim 16, wherein: The support layer is sleeved on the outside of the negative electrode current collector, and the tab passes through the support layer.

19. A battery cell, characterized in that: The invention comprises an electrode assembly according to any one of claims 1 to 18.

20. A battery, characterized in that: The battery cell according to claim 19 is included.

21. An electrical device, characterized in that: Comprising a battery according to claim 20.

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