Positive pole piece, electrode assembly, battery monomer, battery device and power utilization device

Abstract

The invention provides a positive pole piece, an electrode assembly, a battery monomer, a battery device and a power utilization device, the battery monomer comprises the electrode assembly, the electrode assembly comprises a negative pole piece and a positive pole piece, the negative pole piece comprises a negative current collector and a negative film layer, the negative film layer comprises a film main body and a first protruding part, the first protruding part protrudes out of at least one side of the film body in the first direction, and the first direction is perpendicular to the thickness direction. The positive pole piece comprises a positive current collector, a positive film layer and an insulating layer containing an elastic material, the positive film layer and the film body are oppositely arranged in the thickness direction, a first gap is formed between the positive current collector and the first protruding part, and the insulating layer is at least located in the first gap and arranged on the positive current collector; the side face of the positive electrode film layer in the first direction is at least covered. The structural stability of the battery monomer can be improved.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to a positive electrode sheet, an electrode assembly, a battery cell, a battery device, and an electrical device. Background Technology

[0002] Battery cells have characteristics such as high capacity and long lifespan, and are therefore widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] As batteries are used in a wider range of applications, the requirements for battery performance are becoming increasingly stringent, and the structural stability of individual battery cells still needs to be further improved. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a positive electrode sheet, electrode assembly, battery cell, battery device and power supply device that can improve the structural stability of the battery cell.

[0005] In a first aspect, embodiments of this application propose a battery cell, the battery cell including an electrode assembly, the electrode assembly including a negative electrode sheet and a positive electrode sheet, the negative electrode sheet including a negative current collector and a negative electrode film layer, the negative electrode film layer including a negative electrode active material and disposed on at least one side of the negative current collector along the thickness direction of the negative electrode sheet, the negative electrode film layer including a film body and a first protrusion, the first protrusion protruding from at least one side of the film body along a first direction, the first direction being perpendicular to the thickness direction; the positive electrode sheet including a positive electrode current collector, a positive electrode film layer and an insulating layer containing an elastic material, the positive electrode film layer including a positive electrode active material and disposed on at least one side of the positive current collector along the thickness direction, the positive electrode film layer and the film body being disposed opposite each other along the thickness direction, a first gap being formed between the positive current collector and the first protrusion, the insulating layer being at least located within the first gap and disposed on the positive current collector, and at least covering the side of the positive electrode film layer along the first direction.

[0006] As a result, the forces acting on the first protrusion and the membrane body are basically the same, the external forces acting on all parts of the negative electrode membrane are basically the same, and the structure of the negative electrode sheet is not easily damaged, and it is not easy to bend, collapse or break.

[0007] In some embodiments, the first protrusion protrudes from two opposing sides of the membrane body along a first direction; the insulating layer covers at least two opposing sides of the positive electrode membrane along the first direction; thereby further improving and reducing the risk of damage to the negative electrode structure.

[0008] In some embodiments, the negative electrode film layer further includes a second protrusion that protrudes from at least one side of the film body along a second direction, and a second gap is formed between the second protrusion and the positive electrode current collector. The second direction, the first direction, and the thickness direction are perpendicular to each other. An insulating layer is also located within the second gap and disposed in the positive electrode current collector, and covers the side of the positive electrode film layer along the second direction. This can further improve and reduce the risk of damage to the negative electrode structure.

[0009] In some embodiments, the second protrusion protrudes from the two opposite sides of the membrane body along the second direction; the insulating layer also covers the two opposite sides of the positive electrode membrane along the second direction; thereby further improving and reducing the risk of damage to the negative electrode structure.

[0010] In some embodiments, the battery cell further includes a separator located between the positive and negative electrode plates; the separator includes a solid electrolyte layer. The separator can improve the reliability of the battery cell.

[0011] In some embodiments, the battery cell further includes a insulating member, which includes a separator. The insulating member can improve the reliability of the battery cell.

[0012] In some embodiments, the projection of the negative electrode sheet along the thickness direction lies within the projection of the insulating member along the thickness direction; the insulating layer is located between the insulating member and the positive current collector. The insulating member can improve the reliability of the battery cell, and the force exerted by the positive electrode sheet on the negative electrode sheet through the insulating member is basically the same, reducing the risk of damage to the negative electrode sheet structure.

[0013] In some implementations, the surface of the insulating layer facing away from the positive current collector is flush with the surface of the positive electrode film layer facing away from the positive current collector. The force exerted by the positive electrode sheet on the negative electrode sheet through the insulating member is substantially the same, reducing the risk of damage to the negative electrode sheet structure.

[0014] In some embodiments, the insulating member and the positive electrode film are disposed opposite each other in the thickness direction; the insulating layer protrudes from the positive electrode film in the thickness direction and covers the side of the insulating member.

[0015] In some implementations, the surface of the insulating layer facing away from the positive current collector is flush with the surface of the insulating member facing away from the positive current collector. The insulating layer and the insulating member exert essentially the same force on the negative electrode sheet, reducing the risk of damage to the negative electrode sheet structure.

[0016] In some embodiments, the insulating layer further includes an elastic material with a curvature of 0.04 mm at temperatures ranging from 300°C to 1200°C. -1 Up to 0.16mm -1Elastic materials undergo elastic deformation when deformation conditions are triggered, which enables the spacing between adjacent film layers to be basically the same, thereby improving the structural stability of the electrode assembly.

[0017] In some embodiments, the elastic material includes one or more of silicon carbide, alumina, a composite of alumina and zirconium oxide, a composite of alumina and silicon carbide, and a composite of alumina and carbon.

[0018] In some embodiments, the elastic material includes silicon dioxide and aluminum oxide.

[0019] In some embodiments, the insulating layer further includes one or more of silicon oxide, a composite of silicon oxide and aluminum oxide. These materials offer superior insulation properties, thereby improving the reliability of the battery cell.

[0020] In some implementations, the insulating layer comprises a single-layer film.

[0021] In some embodiments, the insulating layer includes a plurality of sublayers stacked along the thickness direction, and at least one of the sublayers includes an elastic material.

[0022] In some embodiments, the multiple sublayers include a first sublayer, a second sublayer, and a third sublayer stacked sequentially along the thickness direction. One of the first and third sublayers comprises aluminum oxide, and the other comprises silicon carbide. The second sublayer comprises a composite of silicon oxide and aluminum oxide. This insulating layer can effectively improve the cycle performance of the battery cell.

[0023] In some embodiments, a first sublayer is disposed on the positive electrode current collector, and the first sublayer includes aluminum oxide; a second sublayer is disposed on the side of the first sublayer facing away from the positive electrode current collector; and a third sublayer is disposed on the side of the second sublayer facing away from the positive electrode current collector, and the third sublayer includes silicon oxide. The aforementioned insulating layer can effectively improve the cycle performance of the battery cell.

[0024] In some embodiments, the battery cell also includes an electrolyte, the water content of the insulating layer is a first water content, the water content of the electrode assembly and the water content of the electrolyte are a second water content, and the percentage of the first water content to the second water content is greater than or equal to 90% and less than 100%.

[0025] Therefore, in the embodiments of this application, an insulating layer is provided at the end of the electrode sheet. The insulating layer can consume water, thereby reducing the water content in the positive and negative electrode film layers and the electrolyte, thereby reducing side reactions in the system and improving the cycle performance of the battery cell.

[0026] Secondly, this application provides an electrode assembly comprising a negative electrode sheet and a positive electrode sheet. The negative electrode sheet includes a negative current collector and a negative electrode film layer. The negative electrode film layer contains a negative active material and is disposed on at least one side of the negative current collector along the thickness direction of the negative electrode sheet. The negative electrode film layer includes a film body and a first protrusion. The first protrusion protrudes from at least one side of the film body along a first direction, which is perpendicular to the thickness direction. The positive electrode sheet includes a positive current collector, a positive electrode film layer, and an insulating layer containing an elastic material. The positive electrode film layer contains a positive active material and is disposed on at least one side of the positive current collector along the thickness direction. The positive electrode film layer and the film body are disposed opposite each other along the thickness direction. A first gap exists between the positive current collector and the first protrusion. The insulating layer is located at least within the first gap and disposed on the positive current collector, and at least covers the side of the positive electrode film layer along the first direction.

[0027] As a result, the forces acting on the first protrusion and the membrane body are basically the same, the external forces acting on all parts of the negative electrode membrane are basically the same, and the structure of the negative electrode sheet is not easily damaged, and it is not easy to bend, collapse or break.

[0028] In some embodiments, the negative electrode film layer further includes a second protrusion that protrudes from at least one side of the film body along a second direction, and a second gap is formed between the second protrusion and the positive electrode current collector. The second direction, the first direction, and the thickness direction are perpendicular to each other. An insulating layer is also located within the second gap and disposed in the positive electrode current collector, and covers the side of the positive electrode film layer along the second direction. This can further improve and reduce the risk of damage to the negative electrode structure.

[0029] In some embodiments, the insulating layer further includes an elastic material with a curvature of 0.04 mm at temperatures ranging from 300°C to 1200°C. -1 Up to 0.16mm -1 Elastic materials undergo elastic deformation when deformation conditions are triggered, which enables the spacing between adjacent film layers to be basically the same, thereby improving the structural stability of the electrode assembly.

[0030] In some embodiments, the elastic material includes one or more of silicon carbide, alumina, a composite of alumina and zirconium oxide, a composite of alumina and silicon carbide, and a composite of alumina and carbon.

[0031] In some embodiments, the elastic material includes silicon dioxide and aluminum oxide.

[0032] In some embodiments, the insulating layer further includes one or more of silicon oxide, a composite of silicon oxide and aluminum oxide. These materials offer superior insulation properties, thereby improving the reliability of the battery cell.

[0033] In some implementations, the insulating layer comprises a single-layer film.

[0034] In some embodiments, the insulating layer includes a plurality of sublayers stacked along the thickness direction, and at least one of the sublayers includes an elastic material.

[0035] In some embodiments, the multiple sublayers include a first sublayer, a second sublayer, and a third sublayer stacked sequentially along the thickness direction. One of the first and third sublayers comprises aluminum oxide, and the other comprises silicon carbide. The second sublayer comprises a composite of silicon oxide and aluminum oxide. This insulating layer can effectively improve the cycle performance of the battery cell.

[0036] In some embodiments, a first sublayer is disposed on the positive electrode current collector, and the first sublayer includes aluminum oxide; a second sublayer is disposed on the side of the first sublayer facing away from the positive electrode current collector; and a third sublayer is disposed on the side of the second sublayer facing away from the positive electrode current collector, and the third sublayer includes silicon oxide. The aforementioned insulating layer can effectively improve the cycle performance of the battery cell.

[0037] Thirdly, this application provides a positive electrode sheet, which includes a positive current collector, a positive electrode film layer, and an insulating layer. The positive electrode film layer is disposed on at least one side of the positive current collector along the thickness direction of the positive electrode sheet, and the positive electrode film layer includes a positive active material. The insulating layer contains an elastic material, is disposed on the positive current collector, and covers the side of the positive electrode film layer along a first direction, which is perpendicular to the thickness direction.

[0038] Fourthly, this application proposes a battery device comprising a battery cell as described in any embodiment of the first aspect of this application.

[0039] Fifthly, this application proposes an electrical device, including a battery device as described in the fourth aspect of this application. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0041] Figure 1 Structural schematic diagrams of the vehicle provided for some embodiments of this application;

[0042] Figure 2 Explosion-proof diagrams of battery devices provided for some embodiments of this application;

[0043] Figure 3 Schematic diagram of the structure of a battery module provided for some embodiments of this application

[0044] Figure 4 Schematic diagrams of the structure of a battery cell provided for some embodiments of this application;

[0045] Figure 5 An exploded schematic diagram of a battery cell provided for some embodiments of this application;

[0046] Figure 6 A schematic diagram of the structure of the electrode assembly of a battery cell provided in some embodiments of this application;

[0047] Figure 7 A schematic diagram of the structure of the positive electrode sheet of a battery cell provided in some embodiments of this application;

[0048] Figure 8 A schematic diagram of the structure of the positive electrode sheet of a battery cell provided in other embodiments of this application;

[0049] Figure 9 A schematic diagram of the electrode assembly of a battery cell provided for other embodiments of this application;

[0050] Figure 10 A schematic diagram of the structure of the positive electrode sheet of a battery cell provided in some other embodiments of this application;

[0051] Figure 11 A schematic diagram of the structure of the positive electrode sheet of a battery cell provided for some other embodiments of this application;

[0052] Figure 12 A schematic diagram of the structure of the electrode assembly of a battery cell provided for some other embodiments of this application;

[0053] Figure 13 A schematic diagram of the structure of the positive electrode sheet of a battery cell provided for some other embodiments of this application;

[0054] Figure 14 A schematic diagram of the structure of the positive electrode sheet of a battery cell provided for some other embodiments of this application;

[0055] The accompanying drawings may not be drawn to scale.

[0056] The annotations in the attached figures are explained as follows:

[0057] X, thickness direction; Y, first direction; Z, second direction;

[0058] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Housing space; 6. Battery module; 7. Battery cell;

[0059] 10. Electrode assembly; 11. Electrode tab; 111. First electrode tab; 112. Second electrode tab; 12. Main body;

[0060] 20. Outer shell; 21. Housing; 22. End cap;

[0061] 30. Negative electrode sheet; 31. Negative electrode current collector; 32. Negative electrode film layer; 321. Membrane body; 322. First protrusion; 323. Second protrusion;

[0062] 40. Positive electrode sheet; 41. Positive current collector; 42. Positive electrode film layer; 421. First side surface; 422. Second side surface; 43. Insulating layer; 431. First insulating portion; 432. Second insulating portion; 433. First sublayer; 434. Second sublayer; 435. Third sublayer;

[0063] 50. Isolation component; 51. Third side;

[0064] 61. First gap; 62. Second gap. Detailed Implementation

[0065] The following detailed description discloses embodiments of the positive electrode, battery cell, battery device, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0066] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0067] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0068] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0069] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0070] In this application, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations.

[0071] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0072] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

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

[0074] In this application, "multiple" refers to two or more (including two). In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used.

[0075] In this application, the battery cell may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium lithium-ion battery cells, sodium-ion battery cells, magnesium-ion battery cells, lithium metal battery cells, sodium metal batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited to these shapes either. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these types either.

[0076] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery device mentioned in this application may include a battery module or a battery pack. A battery device generally includes a housing for encapsulating one or more battery cells. The housing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0077] A battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode and a negative electrode. The battery cell mainly relies on the movement of active ions, such as lithium ions, between the positive and negative electrode components to function. In related technologies, in order to ensure that most of the lithium ions extracted from the positive electrode can be embedded in the negative electrode, the size of the negative electrode is usually larger than that of the positive electrode. When the battery cell is subjected to external forces, the end of the negative electrode that extends beyond the positive electrode is prone to cracking, and may bend, collapse, or even break, thus damaging the structure of the negative electrode and deteriorating the reliability of the battery cell.

[0078] In view of this, the present application improves the electrode assembly by providing an insulating layer at the end of the positive electrode sheet. The insulating layer includes an elastic material, which can effectively fill the gap between the positive electrode sheet and the negative electrode sheet, reduce the risk of cracks at the end of the negative electrode sheet, reduce the risk of bending, collapse, and breakage, improve the structural stability of the negative electrode sheet, and enhance the reliability of the battery cell.

[0079] The battery cells described in this application are applicable to battery devices and electrical devices that use battery devices.

[0080] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of this application do not impose special limitations on the above-mentioned electrical devices.

[0081] For ease of explanation, the following implementation method uses a vehicle as an example of an electrical device.

[0082] Figure 1 A schematic diagram of the vehicle structure provided for some embodiments of this application.

[0083] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0084] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0085] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0086] Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application. For example... Figure 2 As shown, the battery device 2 includes a housing 5 and individual battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0087] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one open end, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one open side, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0088] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0089] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0090] In battery device 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells are connected in both series and parallel. Multiple battery cells can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of multiple battery cells is housed in housing 5. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed manner to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed manner to form a whole assembly, which is then housed in housing 5.

[0091] A single battery cell can be the smallest unit that makes up a battery.

[0092] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0093] In some implementations, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0094] Multiple battery cells 7 in battery module 6 can be electrically connected through busbars to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two battery cells 7.

[0095] Figure 4 This is a schematic diagram of the structure of a battery cell 7 provided in some embodiments of this application; Figure 5 for Figure 4 The diagram shows an exploded view of battery cell 7.

[0096] like Figure 4 and Figure 5 As shown, in some embodiments, the battery cell 7 includes an electrode assembly 10 and a housing 20, with the electrode assembly 10 housed within the housing 20.

[0097] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.

[0098] The housing 21 is a component used to cooperate with the end cap 22 to form the internal cavity of the battery cell 7. The formed internal cavity can accommodate the electrode assembly 10, the electrolyte, and other components. The housing 21 can be of various shapes, such as a cylinder or a cuboid. The shape of the housing 21 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, the housing 21 can be a cylindrical structure. If the electrode assembly 10 has a cuboid structure, the housing 21 can be a cuboid structure.

[0099] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc. The embodiments of this application do not impose any special restrictions on this.

[0100] The electrode assembly 10 housed within the housing 21 may be one or more.

[0101] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the battery cell 7.

[0102] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0103] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0104] From the external shape of the electrode assembly 10, the electrode assembly 10 includes an electrode tab portion 11 and a main body portion 12. The electrode tab portion 11 includes a first electrode tab 111 and a second electrode tab 112. The first electrode tab 111 and the second electrode tab 112 have opposite polarities and extend beyond the main body portion 12. The first electrode tab 111 is the portion of the first electrode sheet that is not coated with an active material layer, and the second electrode tab 112 is the portion of the second electrode sheet that is not coated with an active material layer. The first electrode tab 111 and the second electrode tab 112 are used to draw out the current in the main body portion 12. The first electrode sheet and the second electrode sheet have opposite polarities; in other words, one of the first electrode sheet and the second electrode sheet is a positive electrode sheet, and the other of the first electrode sheet and the second electrode sheet is a negative electrode sheet.

[0105] Taking the first tab 111 as the positive tab and the second tab 112 as the negative tab as an example, the portion of the negative electrode current collector in the negative electrode sheet that is not coated with an active material layer is the negative electrode tab. The active material coated on the negative electrode current collector in the negative electrode sheet constitutes the negative electrode film layer. The negative electrode film layer and the portion of the negative electrode current collector coated with active material are part of the main body 12. Similarly, the portion of the positive electrode current collector in the positive electrode sheet that is not coated with an active material layer is the positive electrode tab. The active material coated on the positive electrode current collector in the positive electrode sheet constitutes the positive electrode film layer. The positive electrode film layer and the portion of the positive electrode current collector coated with active material are part of the main body 12.

[0106] The positive electrode tab and the negative electrode tab can be drawn from the same end of the main body 12, or the positive electrode tab and the negative electrode tab can be drawn from opposite ends of the main body 12.

[0107] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 7, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. Optionally, the electrode assembly 10 also includes a separator disposed between the positive and negative electrodes, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0108] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0109] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0110] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, silver-surfaced aluminum, or stainless steel can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0111] As an example, when the battery cell 7 in this embodiment is a lithium-ion battery or a lithium metal battery, the positive electrode active material may include one or more of the following materials: phosphates, layered transition metal oxides, and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxides and their respective modified compounds, which is beneficial to improving the energy density of the battery cell 7. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode film layer of a battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0112] Examples of phosphates may include, but are not limited to, one or more of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0113] Layered transition metal oxides include those with the general formula Li a Ni b Co c M d O e A f One or more of the compounds and their modified compounds. 0.8≤a≤1.2, 0.3≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes one or more of N, F, S and Cl.

[0114] Examples of layered transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 One or more of O2 and its modified compounds.

[0115] When the battery cell 7 in the embodiments of this application is a sodium-ion battery or a sodium metal battery, the positive electrode active material may include, but is not limited to, one or more of sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0116] As an example, positive electrode active materials for sodium-ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In the given condition, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes H. + Li + Na+ K + and NH4 + One or more of the following, M' is a transition metal cation, optionally one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0117] In the embodiments of this application, the modified compounds of the above-mentioned positive electrode active materials can be doped and / or surface coated to modify the positive electrode active materials, such as carbon coating modification, fast ion conductor coating modification, etc.

[0118] During the charging and discharging process, the battery cell 7 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the battery cell 7 at different discharge states. In the examples of positive electrode active materials in this application, the molar content of Li refers to the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to the battery system, the molar content of Li may change after charge-discharge cycles.

[0119] In the embodiments of this application, the molar content of oxygen (O) in the positive electrode active materials is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of oxygen (O) to change. In reality, the molar content of oxygen (O) will fluctuate.

[0120] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, a positive electrode film layer may or may not be provided on the surface of the foamed metal. As an example, lithium source material, potassium metal, or sodium metal may also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0121] In some embodiments, the positive electrode film layer may optionally include a positive electrode conductive agent. This application does not impose particular limitations on the type of positive electrode conductive agent. As an example, the positive electrode conductive agent includes one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode film layer is ≤5 wt%.

[0122] In some embodiments, the positive electrode film layer may optionally include a positive electrode binder. This application does not impose particular limitations on the type of positive electrode binder. As an example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode film layer is ≤5 wt%.

[0123] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, optional conductive agent, optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0124] In some embodiments, the battery cell is an ion-type battery such as a lithium-ion battery, and the negative electrode can be a negative electrode sheet. The negative electrode sheet can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector. The negative electrode film layer includes a negative electrode active material.

[0125] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0126] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0127] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 7. As an example, the negative electrode active material may include one or more of the following materials: carbon materials (e.g., carbon materials include one or more of artificial graphite, natural graphite, soft carbon, and hard carbon), silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode films may also be used. These negative electrode films may be used alone or in combination of two or more.

[0128] In some embodiments, the negative electrode film layer may optionally include a negative electrode conductive agent. This application does not impose particular limitations on the type of negative electrode conductive agent. As an example, the negative electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon fibers. In some embodiments, the mass percentage of the negative electrode conductive agent in the negative electrode film layer is ≤5 wt%.

[0129] In some embodiments, the negative electrode film layer may optionally include a negative electrode binder. This application does not impose particular limitations on the type of negative electrode binder. As an example, the negative electrode binder may include one or more of the following: styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage of the negative electrode binder in the negative electrode film layer is ≤5 wt%.

[0130] In some embodiments, the negative electrode film layer may optionally include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of other additives in the negative electrode film layer is ≤2 wt%.

[0131] In some embodiments, the battery cell 7 also includes an electrolyte. During the charging and discharging process of the battery cell, active ions move back and forth between the positive and negative electrode plates, inserting and extracting. The electrolyte acts as a conductor for the active ions between the positive and negative electrode plates. The embodiments of this application do not impose any particular limitation on the type of electrolyte; it can be selected according to actual needs.

[0132] Electrolytes can include one or more of solid electrolytes or liquid electrolytes. When using a solid electrolyte, it can be used alone or in combination with a liquid electrolyte, i.e., an electrolyte solution.

[0133] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, and polymer solid electrolytes.

[0134] Sulfide solid electrolytes include one or more of the following: sulfide crystalline solid electrolytes, sulfide glass, and glass-ceramic solid electrolytes.

[0135] In some embodiments, the sulfide solid electrolyte includes Li 10 GeP2S 12 Li6PS5Cl, Li 10 Sn P2S 12 One or more of Li2S-P2S5, Li2S-SiS2 and Li2S-B2S3.

[0136] Oxide solid electrolytes are classified into two categories according to their material structure: crystalline oxide electrolytes and glassy oxide electrolytes (amorphous oxide electrolytes). Crystalline oxide electrolytes include one or more types such as perovskite, NASICON, LISICON, and garnet, while glassy oxide electrolytes include LiPON type electrolytes.

[0137] In some embodiments, the oxide solid electrolyte includes Li 3.3 La 0.56 TiO3, LiTi2(PO4)3, Li 14 Zn(GeO4)4, Li7La3Zr2O 12 Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 2), Li 7-a La3Zr 2-a M a O 12 (M includes one or more of Ta and Nb; 0 < a < 2), Li b La 2 / 3-b TiO3 (0 < b < 2), LiAlO2, Li2ZrO3 and Li4Ti5O 12 One or more of them.

[0138] In some embodiments, the halide solid electrolyte includes one or more of Li3YCl6, Li3ErCl6, Li3YBr6, Li3InBr6, and Li3InCl6.

[0139] Polymer solid electrolytes (SPEs) are primarily composed of a polymer matrix and an electrolyte salt. The electrolyte salt may include lithium salts, specifically one or more of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), and lithium tetrafluoroborate (LiBF4). The electrolyte salt may also include sodium salts, specifically one or more of sodium hexafluorophosphate (NaPF6), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), and sodium tetrafluoroborate (NaBF4).

[0140] In some embodiments, the SPE includes one or more of the following: epoxy compounds, polyester compounds, polyalkoxy compounds, polyolefin compounds, polyacrylonitrile (PAN), and monoionic polymer electrolytes. For example, epoxy compounds include one or more of polyethylene oxide (PEO) and polypropylene oxide (PPO). Polyolefin compounds include one or more of polyvinylidene fluoride (PVDF) and polyvinylidene chloride (PVDC). Polyester compounds include one or more of polycarbonate compounds and polymethyl methacrylate (PMMA). Polycarbonate compounds include one or more of polypropylene carbonate and polytrimethylene carbonate.

[0141] Furthermore, the polymer matrix can be hybridized with inorganic particles, including metal oxide nanoparticles such as MgO, Al2O3, and SiO2, as well as one or more of zeolites and montmorillonite. The addition of inorganic particles can reduce crystallinity, and the interactions between the polymer matrix, lithium salt, and inorganic particles can improve conductivity and ion transference number. Inorganic particles can also adsorb trace impurities such as moisture in the electrolyte and improve mechanical properties.

[0142] In some embodiments, the electrolyte includes an electrolyte salt and a solvent. The types of electrolyte salt and solvent are not specifically limited and can be selected according to actual needs.

[0143] When the battery cell in the embodiments of this application is a lithium-ion battery, as an example, the electrolyte salt may include, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0144] When the battery cell in the embodiments of this application is a sodium-ion battery, as an example, the electrolyte salt may include, but is not limited to, one or more of the following: sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0145] As an example, the solvent may include, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0146] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature power performance.

[0147] In some embodiments, the battery cell 7 also includes a separator. For example, when an electrolyte is used as the electrolyte, the separator can isolate the positive and negative electrodes, reducing the risk of short circuit between them. Of course, when a solid electrolyte is used, the battery cell 7 may also include a separator.

[0148] The embodiments of this application do not have any particular restrictions on the type of separator membrane, and any known porous structure separator membrane with good chemical and mechanical stability can be selected.

[0149] The embodiments of this application do not have any particular restrictions on the type of separator membrane, and any known porous structure separator membrane with good chemical and mechanical stability can be selected.

[0150] In some embodiments, the material of the separator may include one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may 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 may be the same or different, without particular limitation.

[0151] In some embodiments, the separator may include a porous base membrane and a coating disposed on at least one side of the porous base membrane, the coating including one or more of inorganic or organic particles.

[0152] Porous base membranes may include one or more of polyethylene and polypropylene.

[0153] Inorganic particles possess good heat resistance, which can improve the overall heat resistance of the separator. Within the operating voltage range of sodium-ion batteries, inorganic particles essentially do not undergo oxidation and reduction reactions with metal dendrites. In other words, inorganic particles are configured to prevent oxidation and reduction reactions with alkali metals and / or alkaline earth metals at the nominal voltage of sodium-ion batteries.

[0154] In some embodiments, the inorganic particles include one or more of boehmite γ-AlOOH, aluminum oxide Al2O3, aluminum hydroxide Al(OH)3, barium sulfate BaSO4, magnesium oxide MgO, magnesium hydroxide Mg(OH)2, calcium oxide CaO, cerium oxide CeO2, zirconium titanate SrTiO3, barium titanate BaTiO3, and magnesium fluoride MgF2.

[0155] In some embodiments, the organic particles include one or more of polystyrene, polyethylene, polyimide, melamine resin, phenolic resin, polypropylene, polyester (e.g., polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), polyphenylene sulfide, polyarylamide, polyamide-imide, polyimide, copolymers of butyl acrylate and ethyl methacrylate, and mixtures thereof.

[0156] In this embodiment, the electrode assembly 10 is a wound structure or a stacked structure, and can be selected as a stacked structure.

[0157] The electrode assembly 10 has a wound structure, the positive electrode 40 has a solid structure, and the negative electrode 30 has a solid structure. The positive electrode 40 and the negative electrode 30 are wound in the same direction.

[0158] like Figures 6 to 8As shown, when the electrode assembly 10 has a stacked structure, there are multiple positive electrode sheets 40 and multiple negative electrode sheets 30. The positive electrode sheets 40 and negative electrode sheets 30 are stacked alternately. The thickness of different negative electrode sheets 30 may vary, and the thickness of different positive electrode sheets 40 may also vary. This can cause the interlayer gap between the positive electrode sheets 40 and the negative electrode sheets 30 to be too large or too small. Through the elastic deformation capability of the insulating layer 43, the insulating layer 43 can expand or contract in volume, which helps to make the spacing between the negative electrode sheet 30 and its adjacent layers basically the same. This makes the overall stress on the negative electrode sheet 30 more balanced and less prone to structural damage.

[0159] In some embodiments, the battery cell 7 includes a negative electrode 30 and a positive electrode 40. The negative electrode 30 includes a negative current collector 31 and a negative electrode film 32. The negative electrode film 32 contains a negative active material and is disposed on at least one side of the negative current collector 31 along the thickness direction X of the negative electrode 30. The negative electrode film 32 includes a film body 321 and a first protrusion 322. The first protrusion 322 protrudes from at least one side of the film body 321 along a first direction Y, which is perpendicular to the thickness direction X. The positive electrode... 40 includes a positive current collector 41, a positive electrode film layer 42, and an insulating layer 43 containing an elastic material. The positive electrode film layer 42 contains a positive active material and is disposed on at least one side of the positive current collector 41 along the thickness direction X. The positive electrode film layer 42 and the film body 321 are disposed opposite each other along the thickness direction X. A first gap 61 is formed between the positive current collector 41 and the first protrusion 322. The insulating layer 43 is located at least within the first gap 61 and is disposed on the positive current collector 41, and at least covers the side of the positive electrode film layer 42 along the first direction Y.

[0160] Along the first direction Y, the negative electrode film layer 32 extends beyond the positive electrode film layer 42. The portion of the negative electrode film layer 32 extending beyond the positive electrode film layer 42 is defined as the first protrusion 322, and the portion not extending beyond the positive electrode film layer 42 is defined as the film body 321. The film body 321 and the positive electrode film layer 42 are disposed opposite to each other along the thickness direction X. There may be no clear boundary between the film body 321 and the first protrusion 322, that is, the film body 321 and the first protrusion 322 are an integral structure; of course, the film body 321 and the first protrusion 322 may use different coating components, so that there is a boundary between the film body 321 and the first protrusion 322.

[0161] The first protrusion 322 protrudes from the positive electrode film layer 42, creating a first gap 61 between the first protrusion 322 and the positive electrode current collector 41. The presence of this first gap 61 causes a difference in the forces acting on the membrane body 321 and the first protrusion 322 when the negative electrode sheet 30 is subjected to external force. In particular, the connection between the membrane body 321 and the first protrusion 322 is prone to bending, collapse, or even breakage. In this embodiment, an insulating layer 43 is provided within the first gap 61 and is disposed on the positive electrode current collector 41. The insulating layer 43 comprises an elastic material with elastic deformation capability, allowing it to expand or contract in volume. This allows the insulating layer 43 to fill the gap between the insulating layer 43 and the positive electrode film layer 42 through volume changes, for example, by contacting the side of the positive electrode film layer 42 along the first direction Y to cover the side of the positive electrode film layer 42 along the first direction Y. The insulating layer 43 can also fill at least part of the space in the first gap 61 by volume expansion or volume contraction. When the insulating layer 43 applies an external force to the first protrusion 322 and the positive electrode film layer 42 applies an external force to the film body 321, the forces on the first protrusion 322 and the film body 321 are basically the same, so that the external forces on the negative electrode film layer 32 are basically the same, making the negative electrode sheet 30 less prone to cracking, its structure less prone to damage, and less prone to bending, collapse and breakage.

[0162] In this embodiment, the length direction of the positive electrode 40 is parallel to the length direction of the negative electrode 30, the width direction of the positive electrode 40 is parallel to the width direction of the negative electrode 30, and the thickness direction X of the positive electrode 40 is parallel to the thickness direction X of the negative electrode 30. A first direction Y is parallel to the length direction of the negative electrode 30, or the first direction Y is parallel to the width direction of the negative electrode 30. When the first direction Y is parallel to the length direction of the negative electrode 30, the second direction Z is parallel to the width direction of the negative electrode 30. When the first direction Y is parallel to the width direction of the negative electrode 30, the second direction Z is parallel to the length direction of the negative electrode 30.

[0163] The two opposing sides of the positive electrode film layer 42 along the first direction Y are defined as two first sides 421. The two opposing sides of the positive electrode film layer 42 along the second direction Z are defined as two second sides 422.

[0164] In this embodiment, the first protrusion 322 protrudes from at least one side of the membrane body 321 along the first direction Y. For example, the first protrusion 322 protrudes from one side of the membrane body 321 along the first direction Y, or the first protrusion 322 protrudes from both sides of the membrane body 321 along the first direction Y.

[0165] When the first protrusion 322 protrudes from the membrane body 321 on one side along the first direction Y, a first gap 61 is formed between the first protrusion 322 and the positive current collector 41; correspondingly, the insulating layer 43 is located within the first gap 61 and covers the first side surface 421 of the positive electrode membrane layer 42. In the embodiments of this application, the insulating layer 43 located within the first gap 61 can be defined as a first insulating portion 431, which covers the first side surface 421 of the positive electrode membrane layer 42. Figure 7 The first side surface 421 of the first insulating portion 431 covering one side of the positive electrode film layer 42 is shown.

[0166] With the first protrusion 322 protruding from both sides of the membrane body 321 along the first direction Y, there are two first gaps 61 between the first protrusion 322 and the positive current collector 41; correspondingly, the first insulating part 431 is located within the two first gaps 61 and covers the two first sides 421 of the positive electrode membrane layer 42. The first insulating part 431 applies an external force to the first protrusions 322 on both sides of the negative electrode sheet 30, and the positive electrode membrane layer 42 applies an external force to the membrane body 321. The forces on the first protrusions 322 and the membrane body 321 on both sides are basically the same, so that the external forces on the negative electrode membrane layer 32 along the first direction Y are basically the same, making the structure of the negative electrode sheet 30 less prone to damage, bending, collapse and breakage. Figure 8 The first insulating portion 431 covers the first side surface 421 on both sides of the positive electrode film layer 42. The dimensions of the first insulating portions 431 on both sides along the first direction Y may be equal or unequal.

[0167] like Figures 9 to 11 As shown, in some embodiments, the negative electrode film layer 32 may further include a second protrusion 323, which protrudes from at least one side of the film body along the second direction Z. The second protrusion 323 has a second gap 62 with the positive electrode current collector 41. The second direction Z, the first direction Y, and the thickness direction X are all perpendicular to each other. The negative electrode film layer 32 includes a first protrusion 322 and a second protrusion 323, and the negative electrode film layer 32 extends beyond the positive electrode film layer 42 in both the length and width directions.

[0168] In some embodiments, the insulating layer 43 is also located within the second gap 62 and disposed on the positive electrode current collector 41, covering the side surface of the positive electrode film layer 42 along the second direction Z. In the embodiments of this application, the insulating layer 43 located within the second gap 62 can be defined as a second insulating portion 432, which covers the second side surface 422 of the positive electrode film layer 42.

[0169] The second insulating portion 432 has the ability to expand or contract in volume. The second insulating portion 432 can fill the gap between the second insulating portion 432 and the positive electrode film layer 42 through volume change, for example, by covering the second side 422 of the positive electrode film layer 42. The second insulating portion 432 can also fill at least a portion of the space in the second gap 62 through volume expansion or contraction. When the second insulating portion 432 applies an external force to the second protrusion 323 of the negative electrode sheet 30, and the positive electrode film layer 42 applies an external force to the film body 321, the forces acting on the second protrusion 323 and the film body 321 are essentially the same. This ensures that the external forces acting on the negative electrode film layer 32 are essentially the same at all points along the second direction Z, making the structure of the negative electrode sheet 30 less susceptible to damage, bending, collapse, and breakage.

[0170] When the second protrusion 323 protrudes from the membrane body 321 on one side along the second direction Z, there is a second gap 62 between the second protrusion 323 and the positive current collector 41; correspondingly, the second insulating portion 432 in the insulating layer 43 is located in the second gap 62 and covers the second side surface 422 of the positive electrode membrane layer 42. Figure 10 The second side 422 of the second insulating portion 432 covering one side of the positive electrode film layer 42 is shown.

[0171] With the second protrusion 323 protruding from both sides of the membrane body 321 along the second direction Z, there are two second gaps 62 between the second protrusion 323 and the positive current collector 41; correspondingly, the second insulating portion 432 is located within the two second gaps 62 and covers the two second sides 422 of the positive electrode membrane layer 42. The second insulating portion 432 applies an external force to the second protrusion 323 on both sides of the negative electrode sheet 30, and the positive electrode membrane layer 42 applies an external force to the membrane body 321. The forces on the second protrusion 323 and the membrane body 321 on both sides are basically the same, so that the external forces on the negative electrode membrane layer 32 along the second direction Z are basically the same, making the structure of the negative electrode sheet 30 less susceptible to damage, bending, collapse, and breakage. Figure 11 The second insulating portion 432 covers the second side surface 422 on both sides of the positive electrode film layer 42. The dimensions of the second insulating portions 432 on both sides along the second direction may be equal or unequal.

[0172] like Figures 9 to 11 As shown, in some embodiments, the battery cell 7 further includes an insulating member 50 located between the positive electrode 40 and the negative electrode 30. The insulating member 50 is essentially non-conductive to prevent direct contact between the positive electrode 40 and the negative electrode 30; however, active ions such as lithium ions can migrate between the positive electrode 40 and the negative electrode 30 through the insulating member 50.

[0173] For example, the insulating member 50 includes a solid electrolyte layer, the specific types and structures of which have been described above and will not be repeated here. As another example, the insulating member 50 includes a separating membrane, the types and structures of which have been described above and will not be repeated here.

[0174] The insulating member 50 is located between the positive electrode 40 and the negative electrode 30. The insulating member 50 can completely cover the negative electrode 30. In this case, the size of the insulating member 50 is greater than or equal to the size of the negative electrode 30. In other words, the projection of the negative electrode 30 along the thickness direction X lies within the projection of the insulating member 50 along the thickness direction X, and the thickness direction X is parallel to the normal of the projection. With this arrangement, the insulating member 50 can effectively isolate the positive electrode 40 and the negative electrode 30, reducing the risk of short circuits caused by direct contact between them.

[0175] An insulating layer 43 is disposed on the positive current collector 41, and the insulating layer 43 is located between the insulating member 50 and the positive current collector 41. Furthermore, the surface of the insulating layer 43 facing away from the positive current collector 41 is flush with the surface of the positive electrode film layer 42 facing away from the positive current collector 41. In the thickness direction X, the spacing between the positive electrode sheet 40 and the negative electrode sheet 30 is basically the same. When the electrode assembly 10 is subjected to external force, the force acting on the negative electrode sheet 30 is basically the same. The end of the negative electrode sheet 30 is not easily damaged, which can improve the structural stability of the negative electrode sheet 30, thereby improving the structural stability of the electrode assembly 10 and improving the reliability of the battery cell 7. Figure 9 In the diagram, S1 represents the surface of the insulating layer 43 facing away from the positive current collector 41, and S2 represents the surface of the positive electrode film layer 42 facing away from the positive current collector 41.

[0176] Furthermore, the insulating layer 43 is in contact with the insulating member 50, such as the solid electrolyte layer. One surface of the solid electrolyte layer along its thickness direction is in contact with the negative electrode film layer, and a portion of the other surface of the solid electrolyte layer along its thickness direction is in contact with the insulating layer 43, while another portion is in contact with the positive electrode film layer 42. Based on this structure, the positive electrode 40 exerts a force on the negative electrode 30 through the solid electrolyte layer, and the force borne by the negative electrode 30 at various points is substantially the same, making the structure of the negative electrode 30 more stable. In the embodiment of this application, when the solid electrolyte layer is in contact with the negative electrode film layer, the distance between the solid electrolyte layer and the negative electrode film layer is 0. In other words, when two adjacent film layers are in contact, the distance between the two adjacent film layers is 0.

[0177] Furthermore, the insulating layer 43 is in contact with the insulating member 50, such as a separator. One surface of the separator along its thickness direction is in contact with the negative electrode film layer, and a portion of the other surface of the separator along its thickness direction is in contact with the insulating layer 43, while another portion is in contact with the positive electrode film layer 42. Based on this structure, the positive electrode 40 applies a force to the negative electrode 30 through the separator, and the forces borne by the negative electrode 30 are essentially the same, making the structure of the negative electrode 30 more stable.

[0178] like Figure 12 As shown, the negative electrode 30 can completely cover the insulating member 50. For example, the size of the negative electrode 30 is larger than the size of the insulating member 50. This arrangement means that the end of the negative electrode 30 is not isolated by the insulating member 50, which poses a risk of short-circuiting with the positive electrode 40. However, in this embodiment, an insulating layer 43 is provided at the end of the positive electrode 40. The insulating layer 43 also has the function of isolating the positive electrode 40 and the negative electrode 30. Together with the insulating member 50, it can effectively isolate the positive electrode 40 and the negative electrode 30.

[0179] The insulating layer 43 protrudes from the positive electrode film layer 42 along the thickness direction X. The insulating layer 43 can cover the side of the insulating member 50 through volume expansion or contraction, or in other words, the insulating layer 43 contacts the side of the insulating member 50. The side of the insulating member 50 can be defined as the third side 51. The insulating layer 43 and the insulating member 50 together block the positive electrode sheet 40 and the negative electrode sheet 30; moreover, the insulating layer 43 and the insulating member 50 exert a force on the negative electrode sheet 30, making the force on the negative electrode sheet 30 basically the same at all points, reducing the risk of structural damage at the end of the negative electrode sheet 30. When the insulating layer 43 is located on both sides of the positive electrode current collector 41, for example, when the insulating layer 43 is located on both sides of the positive electrode current collector 41 along the first direction Y, the insulating member 50 is located between the two insulating layers 43. For another example, when the insulating layer 43 is located on both sides of the positive electrode current collector 41 along the second direction Z, the insulating member 50 is still located between the two insulating layers 43.

[0180] Furthermore, the surface of the insulating layer 43 facing away from the positive current collector 41 is flush with the surface of the insulating member 50 facing away from the positive current collector 41. In the thickness direction X, the spacing between the insulating layer 43 and the negative electrode 30, and the spacing between the insulating member 50 and the negative electrode 30 are basically the same. When the electrode assembly 10 is subjected to external force, the force acting on the negative electrode 30 is basically the same at all points. The end of the negative electrode 30 is not easily damaged, which can improve the structural stability of the negative electrode 30, thereby improving the structural stability of the electrode assembly 10 and improving the reliability of the battery cell 7. Figure 12 S1 represents the surface of the insulating layer 43 that is away from the positive current collector 41, and S3 represents the surface of the insulating member 50 that is away from the positive current collector 41.

[0181] Furthermore, the surface of the insulating layer 43 facing away from the positive current collector 41 is in contact with the negative electrode 30; the surface of the insulating member 50 facing away from the positive current collector 41 is in contact with the negative electrode 30, thereby making the overall stress on the negative electrode 30 more even, making the negative electrode 30 less prone to breakage, etc.

[0182] In this embodiment, the insulating layer 43 includes an elastic material. The insulating layer 43 may consist only of the elastic material, or it may further include other materials. The elastic material undergoes elastic deformation when a deformation condition is triggered, such as deformation after stress release or temperature excitation, for example, bending or other deformation. For example, the elastic material is configured to undergo elastic deformation according to temperature changes.

[0183] The elastic deformation capability of the aforementioned material can be achieved by printing the precursor of the material onto a pre-stretched precursor according to a designed pattern to form the corresponding material. When the deformation condition is triggered, the material can deform according to the pattern. The method of printing the pattern can be any method conventional in the art and is not limited in this application.

[0184] In some embodiments, the curvature of the elastic material is 0.04 mm at temperatures ranging from 300°C to 1200°C. -1 Up to 0.16mm -1 For example, 0.04mm -1 0.05mm -1 0.06mm -1 0.07mm -1 0.08mm -1 0.09mm -1 0.10mm -1 0.11mm -1 0.12mm -1 0.13mm -1 0.14mm -1 0.15mm -1 0.16mm -1 Or a range consisting of any two of the above values.

[0185] For example, the curvature of the elastic material at 300°C is 0.04 mm. -1 Up to 0.16mm -1 .

[0186] For example, the curvature of the elastic material at 500°C is 0.04 mm. -1 Up to 0.16mm -1 .

[0187] For example, the curvature of the elastic material at 800°C is 0.04 mm. -1Up to 0.16mm -1 .

[0188] In the embodiments of this application, the curvature of the elastic material can characterize the degree of bending of the elastic material. The smaller the degree of bending, the smaller the curvature; the greater the degree of bending, the greater the curvature. The curvature can be measured using a contact ball diameter meter, such as the SPHERO OptiSpheric from MOLLER in Germany. The curvature is confirmed based on the measured sagitta and the ring radius of the contact ball diameter meter.

[0189] For example, the elastic material may also include one or more of silicon carbide, alumina, a composite of alumina and zirconium oxide, a composite of alumina and silicon carbide, and a composite of alumina and carbon.

[0190] The aforementioned materials can be nanomaterials or submicron materials, such as silicon carbide nanomaterials, alumina nanomaterials, composite nanomaterials of alumina and zirconium oxide, composite nanomaterials of alumina and silicon carbide, nano- and submicron alumina, and micron-sized carbon composites.

[0191] Optionally, the elastic material includes silicon dioxide, which, in addition to its water absorption properties, can also have elastic deformation properties, such as silicon dioxide nanomaterials.

[0192] Optionally, the elastic material includes silicon dioxide and alumina. Silicon dioxide can react with water, consuming water and reducing side reactions in the system, thus improving the cycle performance of the battery cell 7. Silicon dioxide can also react with oxygen, consuming oxygen and reducing system pressure, thereby improving the reliability of the battery cell 7. Furthermore, the product obtained from the reaction of silicon dioxide and water / oxygen can further react with alumina to form mullite, improving the insulation performance of the insulating layer 43.

[0193] The aforementioned elastic material can undergo elastic deformation after stress release or temperature excitation, resulting in a smaller gap between the insulating layer 43 and the negative electrode 30, and the gap between the negative electrode 30 and its adjacent film layers is basically the same at all points. Moreover, alumina has low electrical conductivity and excellent insulation properties; alumina also has good density, which can effectively reduce the risk of external oxygen diffusing into the electrode assembly 10 and improve the stability of the materials in the electrode assembly 10.

[0194] For example, after the insulating layer 43 is disposed on the positive current collector 41, the distance between the insulating layer 43 and the negative electrode 30 may be large. In this case, heating the system causes the insulating material to undergo elastic deformation, such as bending, resulting in an overall volume expansion of the insulating layer 43. The insulating layer 43 expands towards the negative electrode 30, reducing the distance between the insulating layer 43 and the negative electrode 30. The distance between the negative electrode 30 and its adjacent film layers is then essentially the same. When the electrode assembly 10 is subjected to external forces, the force on the negative electrode 30 is essentially the same at all points, making it less prone to problems such as end damage.

[0195] For example, after the insulating layer 43 is placed on the positive current collector 41, the distance between the insulating layer 43 and the negative electrode 30 may be too small, or even non-existent. In this case, the system can be cooled to cause the insulating layer 43 to undergo elastic deformation, such as the material becoming nearly flat and exhibiting overall volume shrinkage of the insulating layer 43. The insulating layer 43 shrinks in the direction away from the negative electrode 30, thus reducing the distance between the insulating layer 43 and the negative electrode 30, and making the distance between the negative electrode 30 and its adjacent film layers basically the same. When the electrode assembly 10 is subjected to external force, the force on the negative electrode 30 is basically the same at all points, making it less prone to problems such as end damage.

[0196] After adjusting the spacing between the negative electrode 30 and its adjacent film layers to be basically the same, the electrode assembly 10 is assembled into the casing to form a battery cell 7.

[0197] In some embodiments, the insulating layer 43 further includes one or more of silicon oxide and a composite of silicon oxide and aluminum oxide. Optionally, the insulating layer 43 further includes a composite of silicon oxide and aluminum oxide. The composite of silicon oxide and aluminum oxide can be mullite. The above materials have a high melting temperature, low thermal conductivity, and low electrical conductivity, making them more stable during the cyclic charging and discharging of the battery cell 7. They can effectively isolate the positive electrode and the negative electrode, further improving the reliability of the battery cell.

[0198] Optionally, the molar ratio of alumina to silicon carbide is from 0.5 to 2, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or any combination of two of the above values. A molar ratio of alumina to silicon carbide within the above range is beneficial for the formation of mullite, improving the thermal expansion capacity of the insulating layer 43.

[0199] In the embodiments of this application, the insulating layer 43 can be a single-layer film or a multi-layer film.

[0200] like Figure 13As shown, when the insulating layer 43 is a single-layer film, the components in the insulating layer 43 are mixed in the same layer. For example, when the insulating layer 43 includes both alumina and silicon carbide, the silicon carbide can consume moisture and oxygen, and the contact between alumina and silicon carbide is more sufficient, making it easier to form mullite, thus making the insulating layer 43 have better insulation properties. Of course, the insulating layer 43 may also include only an elastic material such as silicon carbide.

[0201] like Figure 14 As shown, when the insulating layer 43 is a multilayer film, the insulating layer 43 may include a plurality of sublayers stacked along the thickness direction X. The plurality of sublayers may be two, three, four, five, etc., and at least one of the plurality of sublayers may include an elastic material. The other layers of the plurality of sublayers may include one or more of alumina and silicon carbide.

[0202] Optionally, the multiple sublayers may include a first sublayer 433, a second sublayer 434, and a third sublayer 435 stacked sequentially along the thickness direction X, wherein one of the first sublayer 433 and the third sublayer 435 comprises alumina and the other comprises silicon carbide, and the second sublayer 434 comprises mullite.

[0203] For example, a first sublayer 433 is disposed on the positive electrode current collector 41, and the first sublayer 433 includes alumina; a second sublayer 434 is disposed on the side of the first sublayer 433 facing away from the positive electrode current collector 41, and the second sublayer 434 includes mullite; a third sublayer 435 is disposed on the side of the second sublayer 434 facing away from the positive electrode current collector 41, and the third sublayer 435 includes silicon carbide. Silicon carbide reduces trace water, alumina prevents water and oxygen from entering the electrode assembly 10, and both silicon carbide and alumina provide elastic deformation capability, while mullite improves insulation. This comprehensively improves the deformation performance of the insulating layer 43, its ability to block water and oxygen, and its ability to reduce trace water.

[0204] For example, a first sublayer 433 is disposed on the positive electrode current collector 41, and the first sublayer 433 includes silicon dioxide; a second sublayer 434 is disposed on the side of the first sublayer 433 away from the positive electrode current collector 41, and the second sublayer 434 includes mullite; a third sublayer 435 is disposed on the side of the second sublayer 434 away from the positive electrode current collector 41, and the third sublayer 435 includes aluminum oxide.

[0205] In the embodiments of this application, the insulating layer 43 can be formed by coating methods such as 3D printing (Three Dimensional Printing), 4D printing (Four Dimensional Printing), extrusion coating, and gravure printing.

[0206] In one specific embodiment of this application, the battery cell 7 includes a negative electrode 30 and a positive electrode 40. The negative electrode 30 includes a negative current collector 31 and a negative electrode film 32. The negative electrode film 32 contains a negative electrode active material and is disposed on at least one side of the negative current collector 31 along the thickness direction X of the negative electrode 30. The negative electrode film 32 includes a film body 321, a first protrusion 322, and a second protrusion 323. The first protrusion 322 protrudes from both sides of the film body 321 along the first direction Y, and the second protrusion 323 protrudes from both sides of the film body 321 along the second direction Z. The first direction Y and the second direction Z are perpendicular to the thickness direction X. The positive electrode 40 includes a positive current collector 41, a positive electrode film 42, and an insulating layer 43 containing an elastic material. The membrane layer 42 contains a positive electrode active material and is disposed on at least one side of the positive electrode current collector 41 along the thickness direction X. The positive electrode membrane layer 42 and the membrane body 321 are disposed opposite each other along the thickness direction X. There is a first gap 61 between the positive electrode current collector 41 and the first protrusion 322, and a second gap 62 between the positive electrode current collector 41 and the second protrusion 323. The insulating layer 43 includes a first insulating portion 431 and a second insulating portion 432. The first insulating portion 431 is located in the first gap 61 and disposed in the positive electrode current collector 41, and covers the two first side surfaces 421 of the positive electrode membrane layer 42 along the first direction Y. The second insulating portion 432 is located in the second gap 62 and disposed in the positive electrode current collector 41, and covers the two second side surfaces 422 of the positive electrode membrane layer 42 along the second direction Z.

[0207] As a specific embodiment of this application, the positive electrode sheet 40 includes a positive current collector 41, a positive electrode film layer 42 disposed on both sides of the positive current collector 41 along the thickness direction X of the positive electrode sheet 40, and an insulating layer 43 containing an elastic material. The positive electrode film layer 42 includes a positive electrode active material. The insulating layer 43 is disposed on the positive current collector 41 and covers the first side surface 421 of the positive electrode film layer 42 along the first direction Y, and also covers the second side surface 422 of the positive electrode film layer 42 along the second direction Z. The first direction Y is perpendicular to the thickness direction X.

[0208] Example

[0209] The following embodiments describe the contents disclosed in this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of the embodiments of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0210] Example 1

[0211] 1. Preparation of positive electrode sheet

[0212] Aluminum foil is used as the positive current collector.

[0213] The positive electrode active material, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 97.5:1.4:1.1 to form a uniform positive electrode slurry. The positive electrode slurry was uniformly coated onto the surface of the positive electrode current collector aluminum foil. After drying and cold pressing, a positive electrode film layer was obtained on the positive electrode current collector, forming a positive electrode sheet. The positive electrode active material was lithium iron phosphate.

[0214] An insulating layer is formed around the positive electrode current collector. The insulating layer includes an alumina layer and a silicon dioxide layer. The alumina layer is a film formed by 3D printing an alumina slurry, which is formed by dispersing alumina particles in the solvent N-methylpyrrolidone (NMP), around the positive electrode current collector. The silicon dioxide layer is a film formed by 3D printing a silicon dioxide slurry, which is formed by dispersing silicon dioxide particles in the solvent NMP, onto the alumina layer.

[0215] 2. Preparation of negative electrode sheet

[0216] Copper foil is used as the negative electrode current collector.

[0217] The negative electrode active material graphite, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC-Na), and conductive agent carbon black Super P are mixed thoroughly in an appropriate amount of deionized water at a mass ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry. The negative electrode slurry is then uniformly coated onto the surface of the negative electrode current collector copper foil. After drying and cold pressing, the negative electrode sheet is obtained.

[0218] The negative electrode film includes a film body, a first protrusion, and a second protrusion. There is a first gap between the first protrusion and the positive electrode current collector, and a second gap between the second protrusion and the positive electrode current collector. The insulating layer is located within the first gap and the second gap.

[0219] 3. Preparation of solid electrolytes

[0220] Polyethylene oxide (PEO) and lithium hexafluorophosphate (LiPF6) were added to N,N-dimethylformamide and dispersed evenly to obtain a slurry. The slurry was then molded to obtain a polymer solid electrolyte. The mass ratio of PEO to LiPF6 was 1:0.6.

[0221] 4. Preparation of battery cells

[0222] The positive electrode, solid electrolyte, and negative electrode are stacked in sequence, with the solid electrolyte acting as an insulator between the positive and negative electrodes. The electrode assembly is then obtained through a stacking process. This assembly is placed in an outer packaging shell and undergoes vacuum sealing, settling, formation, and shaping processes to obtain a lithium-ion battery.

[0223] During the formation process, the portion of the silicon dioxide layer near the alumina layer reacts with water and oxygen, and then reacts with the portion of the alumina layer near the silicon dioxide layer to form mullite. After the reaction, the insulating layer includes a silicon dioxide region, a mullite region, and an alumina region arranged sequentially.

[0224] Example 2

[0225] Unlike Example 1, the negative electrode film layer includes a film body, a first protrusion, and a second protrusion. There is a first gap between the first protrusion and the positive electrode current collector, and the insulating layer is located within the first gap.

[0226] Example 3

[0227] Unlike Example 1, the negative electrode film layer includes a film body, a first protrusion, and a second protrusion. There is a second gap between the second protrusion and the positive electrode current collector, and the insulating layer is located in the second gap.

[0228] Example 4

[0229] Unlike Example 1, the positive electrode sheet is prepared as follows:

[0230] Aluminum foil is used as the positive current collector.

[0231] The positive electrode active material, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 97.5:1.4:1.1 to form a uniform positive electrode slurry. The positive electrode slurry was then uniformly coated onto the surface of the positive electrode current collector aluminum foil. After drying and cold pressing, a positive electrode film layer was obtained on the positive electrode current collector, forming the positive electrode sheet. The positive electrode active material was lithium iron phosphate.

[0232] An insulating layer is set around the positive electrode current collector. The insulating layer includes alumina particles and silicon carbide particles. The insulating layer is a film formed by 3D printing of an alumina slurry formed by dispersing alumina particles and silicon carbide particles in the solvent N-methylpyrrolidone (NMP) around the positive electrode current collector.

[0233] Example 5

[0234] Unlike Example 1, the positive electrode sheet is prepared as follows:

[0235] Aluminum foil is used as the positive current collector.

[0236] The positive electrode active material, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 97.5:1.4:1.1 to form a uniform positive electrode slurry. The positive electrode slurry was then uniformly coated onto the surface of the positive electrode current collector aluminum foil. After drying and cold pressing, a positive electrode film layer was obtained on the positive electrode current collector, forming the positive electrode sheet. The positive electrode active material was lithium iron phosphate.

[0237] An insulating layer is provided around the positive electrode current collector. The insulating layer includes silicon dioxide particles. The insulating layer is a film formed by 3D printing of an alumina slurry formed by dispersing silicon dioxide particles in the solvent N-methylpyrrolidone (NMP) around the positive electrode current collector.

[0238] Comparative Example 1

[0239] Unlike Example 1, the positive electrode sheet is prepared as follows:

[0240] Aluminum foil is used as the positive current collector.

[0241] The positive electrode active material, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 97.5:1.4:1.1 to form a uniform positive electrode slurry. The positive electrode slurry was uniformly coated onto the surface of the positive electrode current collector aluminum foil. After drying and cold pressing, a positive electrode film layer was obtained on the positive electrode current collector, forming a positive electrode sheet. The positive electrode active material was lithium iron phosphate.

[0242] An insulating layer is provided around the positive electrode current collector. The insulating layer includes boehmite particles. The alumina layer is a 3D film formed around the positive electrode current collector by dispersing boehmite particles in the solvent N-methylpyrrolidone (NMP).

[0243] 2. Preparation of negative electrode sheet

[0244] Copper foil is used as the negative electrode current collector.

[0245] The negative electrode active material graphite, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC-Na), and conductive agent carbon black Super P are mixed thoroughly in an appropriate amount of deionized water at a mass ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry. The negative electrode slurry is then uniformly coated onto the surface of the negative electrode current collector copper foil. After drying and cold pressing, the negative electrode sheet is obtained.

[0246] The negative electrode film includes a film body, a first protrusion, and a second protrusion. There is a first gap between the first protrusion and the positive electrode current collector, and a second gap between the second protrusion and the positive electrode current collector. The insulating layer is located within the first gap and the second gap.

[0247] 3. Preparation of solid electrolytes

[0248] Polyethylene oxide (PEO) and lithium hexafluorophosphate (LiPF6) were added to N,N-dimethylformamide and dispersed evenly to obtain a slurry. The slurry was then molded to obtain a polymer solid electrolyte. The mass ratio of PEO to LiPF6 was 1:0.6.

[0249] 4. Preparation of battery cells

[0250] The positive electrode, solid electrolyte, and negative electrode are stacked in sequence, with the solid electrolyte acting as an insulator between the positive and negative electrode. The electrode assembly is then obtained through a stacking process. The electrode assembly is placed in an outer packaging shell and then subjected to vacuum sealing, settling, formation, and shaping processes to obtain a lithium-ion battery.

[0251] Performance testing:

[0252] 1. Crack test of negative electrode sheet

[0253] Disassemble the negative electrode plate in the battery cell and use computed tomography (CT) to observe whether there are cracks on the edge of the negative electrode plate.

[0254] 2. Cycle performance test of individual battery cells

[0255] At 25°C, the lithium-ion batteries prepared in the examples and comparative examples were charged to 3.65V at a constant current of 0.33C, and then discharged to 2.5V at a constant current of 0.33C. This constitutes one charge-discharge cycle. Taking the capacity discharged in the first cycle as 100%, the capacity retention rate of the battery after 200 cycles was calculated.

[0256] Test results:

[0257] Table 1

[0258]

[0259] In Table 1,

[0260] In all embodiments and comparative examples, the total water content of the electrode assembly and solid electrolyte is approximately 200 ppm. The water absorption rate is the percentage of the first water content relative to the second water content.

[0261] In all embodiments, both silicon carbide and alumina are designed as elastic materials capable of elastic deformation. At 300°C, the curvature of silicon carbide is 0.12 mm. -1 The curvature of alumina is 0.06 mm. -1 .

[0262] As temperature increases, the degree of deformation and curvature of the material increase.

[0263] Boehmite in Comparative Example 1 does not have the ability to undergo elastic deformation.

[0264] As shown in Table 1, compared to Comparative Example 1 where the insulating layer includes boehmite, boehmite does not have the ability to deform elastically, which causes cracks to appear at the ends of the negative electrode sheet.

[0265] The embodiments of this application incorporate an elastic material, such as silicon carbide, into the insulating layer. This allows the insulating layer to deform elastically, effectively reducing the risk of negative electrode breakage, improving the structural stability of the battery cell, and further enhancing its cycle performance. The insulating layer may also include a water-absorbing material, effectively improving water absorption and thus enhancing the cycle performance of the battery cell. When the insulating layer also includes mullite, its insulation properties are further improved, enhancing the reliability of the battery cell.

[0266] Example 6

[0267] 1. Preparation of positive electrode sheet

[0268] Aluminum foil is used as the positive current collector.

[0269] The positive electrode active material, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) were thoroughly mixed in an appropriate amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 97.5:1.4:1.1 to form a uniform positive electrode slurry. The positive electrode slurry was uniformly coated onto the surface of the positive electrode current collector aluminum foil. After drying and cold pressing, a positive electrode film layer was obtained on the positive electrode current collector, forming a positive electrode sheet. The positive electrode active material was lithium iron phosphate.

[0270] An insulating layer is formed around the positive electrode current collector. The insulating layer includes an alumina layer and a silicon dioxide layer. The alumina layer is a film formed by 3D printing of an alumina slurry, which is composed of alumina particles dispersed in the solvent N-methylpyrrolidone (NMP), around the positive electrode current collector. The silicon dioxide layer is a film formed by 3D printing of a silicon dioxide slurry, which is composed of silicon dioxide particles dispersed in the solvent NMP, onto the alumina layer.

[0271] The molar ratio of aluminum oxide to silicon dioxide is 1.

[0272] After being prepared as a battery cell, part of the alumina layer and part of the silicon dioxide layer react to form mullite, so that the insulating layer includes three sub-layers: an alumina layer, a mullite layer, and a silicon dioxide layer.

[0273] 2. Preparation of negative electrode sheet

[0274] Copper foil is used as the negative electrode current collector.

[0275] The negative electrode active material graphite, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC-Na), and conductive agent carbon black Super P are mixed thoroughly in an appropriate amount of deionized water at a mass ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry. The negative electrode slurry is then uniformly coated onto the surface of the negative electrode current collector copper foil. After drying and cold pressing, the negative electrode sheet is obtained.

[0276] The negative electrode film includes a film body, a first protrusion, and a second protrusion. There is a first gap between the first protrusion and the positive electrode current collector, and a second gap between the second protrusion and the positive electrode current collector. The insulating layer is located within the first gap and the second gap.

[0277] 3. Separating membrane

[0278] Porous polyethylene (PE) film is used as the separator.

[0279] 4. Preparation of electrolyte

[0280] In an environment with a water content of less than 10 ppm, non-aqueous organic solvents ethylene carbonate (EC) and diethyl carbonate (DMC) are mixed at a volume ratio of 1:1 to obtain an electrolyte solvent. Subsequently, lithium salt lithium hexafluorophosphate is mixed with the mixed solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0281] 5. Preparation of battery cells

[0282] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrode to provide isolation. The electrode assembly is then obtained through a stacking process. The electrode assembly is placed in an outer packaging shell, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a lithium-ion battery is obtained.

[0283] During the formation process, the portion of the silicon dioxide layer near the alumina layer reacts with water and oxygen, and then reacts with the portion of the alumina layer near the silicon dioxide layer to form mullite. After the reaction, the insulating layer includes a silicon dioxide region, a mullite region, and an alumina region arranged sequentially.

[0284] In Example 6, the end of the negative electrode sheet is free of cracks; the water absorption rate of the insulating layer is 94%, which can effectively reduce the side reactions in the battery cell and effectively improve the cycle performance of the battery cell.

[0285] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0286] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, comprising an electrode assembly, the electrode assembly comprising: A negative electrode sheet includes a negative electrode current collector and a negative electrode film layer. The negative electrode film layer contains a negative electrode active material and is disposed on at least one side of the negative electrode current collector along the thickness direction of the negative electrode sheet. The negative electrode film layer includes a film body and a first protrusion. The first protrusion protrudes from at least one side of the film body along a first direction, which is perpendicular to the thickness direction. A positive electrode sheet includes a positive current collector, a positive electrode film layer, and an insulating layer containing an elastic material. The positive electrode film layer contains a positive active material and is disposed on at least one side of the positive current collector along the thickness direction. The positive electrode film layer and the film body are disposed opposite each other along the thickness direction. A first gap exists between the positive current collector and the first protrusion. The insulating layer is located at least within the first gap and disposed on the positive current collector, and at least covers the side of the positive electrode film layer along the first direction.

2. The battery cell according to claim 1, wherein, The first protrusion protrudes from the membrane body on two opposite sides along the first direction; The insulating layer covers at least two sides of the positive electrode film layer that are opposite to each other along the first direction.

3. The battery cell according to claim 1 or 2, wherein, The negative electrode film layer further includes a second protrusion, which protrudes from at least one side of the film body along the second direction. The second protrusion has a second gap with the positive electrode current collector. The second direction, the first direction, and the thickness direction are perpendicular to each other. The insulating layer is also located within the second gap and disposed in the positive electrode current collector, and covers the side of the positive electrode film layer along the second direction.

4. The battery cell according to claim 3, wherein, The second protrusion protrudes from the membrane body on two opposite sides along the second direction; The insulating layer also covers two opposing sides of the positive electrode film layer along the second direction.

5. The battery cell according to any one of claims 1 to 4, wherein the battery cell further comprises an insulating member located between the positive electrode and the negative electrode; The insulating component includes a solid electrolyte layer; or the insulating component includes an isolation membrane.

6. The battery cell according to claim 5, wherein, The projection of the negative electrode sheet along the thickness direction lies within the projection of the insulating member along the thickness direction; The insulating layer is located between the insulating member and the positive current collector.

7. The battery cell according to claim 6, wherein, The surface of the insulating layer facing away from the positive current collector is flush with the surface of the positive electrode film layer facing away from the positive current collector.

8. The battery cell according to claim 5, wherein, The insulating component and the positive electrode film layer are disposed opposite to each other along the thickness direction; The insulating layer protrudes from the positive electrode film layer along the thickness direction and covers the side of the insulating member.

9. The battery cell according to claim 8, wherein, The surface of the insulating layer facing away from the positive current collector is flush with the surface of the insulating member facing away from the positive current collector.

10. The battery cell according to any one of claims 1 to 9, wherein, The insulating layer also includes an elastic material with a curvature of 0.04 mm at temperatures ranging from 300°C to 1200°C. -1 Up to 0.16mm -1 .

11. The battery cell according to claim 10, wherein, The elastic material includes one or more of the following: silicon carbide, aluminum oxide, a composite of aluminum oxide and zirconium oxide, a composite of aluminum oxide and silicon carbide, and a composite of aluminum oxide and carbon.

12. The battery cell according to claim 11, wherein, The elastic material includes silicon dioxide and aluminum oxide.

13. The battery cell according to any one of claims 1 to 12, wherein, The insulating layer also includes one or more of silicon oxide, silicon oxide and aluminum oxide composites.

14. The battery cell according to any one of claims 1 to 13, wherein, The insulating layer comprises a single-layer film.

15. The battery cell according to any one of claims 1 to 13, wherein, The insulating layer comprises a plurality of sub-layers stacked along the thickness direction, and at least one of the plurality of sub-layers comprises the elastic material.

16. The battery cell according to claim 15, wherein, The plurality of sublayers include a first sublayer, a second sublayer, and a third sublayer stacked sequentially along the thickness direction, wherein one of the first sublayer and the third sublayer comprises alumina and the other comprises silicon carbide, and the second sublayer comprises a composite of silicon carbide and alumina.

17. The battery cell according to claim 16, wherein, The first sublayer is disposed on the positive electrode current collector, and the first sublayer comprises aluminum oxide; The second sublayer is disposed on the side of the first sublayer away from the positive current collector; The third sublayer is disposed on the side of the second sublayer away from the positive current collector, and the third sublayer comprises silicon oxide.

18. The battery cell according to any one of claims 1 to 17, wherein the battery cell further comprises an electrolyte, the water content of the insulating layer is a first water content, the water content of the electrode assembly and the water content of the electrolyte are a second water content, and the percentage of the first water content to the second water content is greater than or equal to 90% and less than 100%.

19. A battery device comprising a battery cell as claimed in any one of claims 1 to 18.

20. An electrical device comprising the battery device according to claim 19.

21. An electrode assembly, comprising: A negative electrode sheet includes a negative electrode current collector and a negative electrode film layer. The negative electrode film layer contains a negative electrode active material and is disposed on at least one side of the negative electrode current collector along the thickness direction of the negative electrode sheet. The negative electrode film layer includes a film body and a first protrusion. The first protrusion protrudes from at least one side of the film body along a first direction, which is perpendicular to the thickness direction. A positive electrode sheet includes a positive current collector, a positive electrode film layer, and an insulating layer containing an elastic material. The positive electrode film layer contains a positive active material and is disposed on at least one side of the positive current collector along the thickness direction. The positive electrode film layer and the film body are disposed opposite each other along the thickness direction. A first gap exists between the positive current collector and the first protrusion. The insulating layer is located at least within the first gap and disposed on the positive current collector, and at least covers the side of the positive electrode film layer along the first direction.

22. The electrode assembly according to claim 21, wherein, The negative electrode film layer further includes a second protrusion, which protrudes from at least one side of the film body along the second direction. The second protrusion has a second gap with the positive electrode current collector. The second direction, the first direction, and the thickness direction are perpendicular to each other. The insulating layer is also located within the second gap and disposed in the positive electrode current collector, and covers the side of the positive electrode film layer along the second direction.

23. The electrode assembly according to claim 21 or 22, wherein, The insulating layer also includes an elastic material with a curvature of 0.04 mm at temperatures ranging from 300°C to 1200°C. -1 Up to 0.16mm -1 .

24. The electrode assembly according to any one of claims 21 to 23, wherein, The elastic material includes one or more of the following: silicon carbide, aluminum oxide, a composite of aluminum oxide and zirconium oxide, a composite of aluminum oxide and silicon carbide, and a composite of aluminum oxide and carbon.

25. The electrode assembly of claim 24, wherein, The elastic material includes silicon dioxide and aluminum oxide.

26. The electrode assembly according to any one of claims 21 to 25, wherein, The insulating layer also includes one or more of silicon oxide, silicon oxide and aluminum oxide composites.

27. The electrode assembly according to any one of claims 21 to 26, wherein, The insulating layer comprises a single-layer film.

28. The electrode assembly according to any one of claims 21 to 26, wherein, The insulating layer comprises a plurality of sub-layers stacked along the thickness direction, and at least one of the plurality of sub-layers comprises the elastic material.

29. The electrode assembly according to claim 28, wherein, The plurality of sublayers include a first sublayer, a second sublayer, and a third sublayer stacked sequentially along the thickness direction, wherein one of the first sublayer and the third sublayer comprises alumina and the other comprises silicon carbide, and the second sublayer comprises a composite of silicon carbide and alumina.

30. The electrode assembly according to claim 29, wherein, The first sublayer is disposed on the positive electrode current collector, and the first sublayer comprises aluminum oxide; The second sublayer is disposed on the side of the first sublayer away from the positive current collector; The third sublayer is disposed on the side of the second sublayer away from the positive current collector, and the third sublayer comprises silicon oxide.

31. A positive electrode plate, comprising: Positive current collector; A positive electrode film layer is disposed on at least one side of the positive electrode current collector along the thickness direction of the positive electrode sheet, the positive electrode film layer comprising a positive electrode active material; as well as An insulating layer containing an elastic material is disposed on the positive electrode current collector and covers the side of the positive electrode film layer along a first direction, the first direction being perpendicular to the thickness direction.

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