Battery cell, battery device, and electric device

Abstract

The application relates to a battery monomer, a battery device and a power utilization device, which comprise a current collector, an active material layer arranged on one side of the current collector in a thickness direction, and an insulation layer at least partially arranged on the outer side of the active material layer in a first direction, wherein the side of the current collector facing the insulation layer is provided with a first concave-convex structure, and the first concave-convex structure at least partially overlaps the insulation layer in the thickness direction. The application can effectively reduce the falling-off of the insulation layer, further reduce the risk of large self-discharge caused by the puncture of the diaphragm by the wrinkled current collector, solve the problem that the whole vehicle cannot better travel due to large pressure difference, and improve the reliability of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, and power supply device. Background Technology

[0002] With the gradual popularization of new energy technologies, lithium battery technology has continued to develop. Lithium batteries are favored by the new energy industry due to their superior characteristics such as large energy storage capacity, stable power supply, and long service life. A battery consists of a positive electrode, a separator, and a negative electrode, stacked or wound together. The separator is located between the positive and negative electrode. The positive electrode may include a positive current collector and a positive active material, and the negative electrode may include a negative current collector and a negative active material. However, the separator is easily punctured by the positive or negative electrode, and the positive and negative electrode can easily come into contact, making the battery prone to short circuits. Utility Model Content

[0003] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device that can enhance the adhesion between the insulating layer and the current collector surface, reduce the problem of the separator being easily punctured, causing the positive and negative electrode plates to overlap and form a short circuit, thereby reducing the risk of large battery self-discharge.

[0004] In a first aspect, this application provides a battery cell, comprising: a casing having a receiving cavity; an electrode assembly disposed in the receiving cavity, the electrode assembly comprising stacked or wound electrode sheets, the electrode sheets comprising: a current collector comprising a main body portion and a tab portion arranged along a first direction, the tab portion extending from the main body portion along the first direction; an active material layer disposed on one side of the main body portion in the thickness direction; and an insulating layer disposed at least partially on the outside of the active material layer along the first direction, the first direction being perpendicular to the thickness direction of the current collector; wherein, the side of the current collector facing the insulating layer is provided with a first uneven structure, and in the thickness direction, the first uneven structure at least partially overlaps with the insulating layer.

[0005] In the technical solution of this application embodiment, by setting an insulating layer, it is helpful to further isolate the positive and negative electrode plates on the basis of the separator, reducing the problem of contact between the positive and negative electrode plates caused by the current collector piercing the separator. By setting a first concave-convex structure on the side of the current collector facing the insulating layer, the first concave-convex structure at least partially overlaps with the insulating layer. In this way, since the battery undergoes a flattening process and the flattened surface is very close to the edge of the separator and the insulating layer, when the outer ring of the battery wrinkles, the insulating layer is prone to peeling off in pieces. The design of the first concave-convex structure helps to increase the roughness of the current collector surface, thereby increasing the contact area between the current collector and the insulating layer, enhancing the adhesion between the insulating layer and the current collector surface, effectively reducing the peeling of the insulating layer, further reducing the risk of large self-discharge caused by the wrinkled current collector piercing the separator, solving the problem of the whole vehicle not being able to drive well due to large pressure difference, and improving the reliability of the battery cell.

[0006] In some embodiments, along the thickness direction, the insulating layer completely covers the first uneven structure in the orthogonal projection of the current collector.

[0007] By setting the insulating layer to completely cover the first uneven structure, the bonding strength between the first uneven structure and the insulating layer can be improved, and the risk of the insulating layer falling off can be reduced.

[0008] In some embodiments, the cross-sectional shape of the first convex-concave structure along the thickness direction includes at least one of strip, arc, or square; wherein the extending direction of the first convex-concave structure is the same as the extending direction of the insulating layer.

[0009] By setting the first concave-convex structure, various shapes can be provided, offering diverse options for the bonding between the current collector and the insulating layer and improving flexibility; by setting the extension direction of the first concave-convex structure to be the same as the extension direction of the insulating layer, the two can fit tightly together in the same direction, further increasing the contact area and improving the adhesion between the current collector and the insulating layer.

[0010] In some embodiments, the dimension of the first concave-convex structure along its own thickness direction is H1, wherein H1 satisfies the condition: 1μm≤H1≤100μm.

[0011] By setting the thickness dimension of the first concave-convex structure to between 1μm and 100μm, on the one hand, an excessively thin first concave-convex structure cannot effectively increase the contact area between the current collector and the insulating layer, resulting in poor adhesion; on the other hand, an excessively thick first concave-convex structure may lead to excessive rigidity of the structure, which can easily cause stress concentration when the battery charge and discharge volume changes. Therefore, within a suitable thickness range, the adhesion between the current collector and the insulating layer can be effectively improved, while also reducing the problem of stress concentration.

[0012] In some embodiments, the dimension of the first concave-convex structure along the first direction is W1, and W1 satisfies the condition: 1mm≤W1≤10mm.

[0013] By setting the dimension of the first concave-convex structure along the first direction to between 1 mm and 10 mm, the first concave-convex structure can fully contact the insulating layer within a suitable width range, thereby increasing the contact area and enhancing the adhesion between the current collector and the insulating layer.

[0014] In some embodiments, the surface of the current collector facing the insulating layer is a first surface; the first uneven structure includes a plurality of protrusions that protrude from the first surface.

[0015] By setting multiple protrusions, these protrusions can fully contact the insulating layer, thereby enhancing the adhesion between the current collector and the insulating layer; at the same time, when the battery undergoes volume changes during charging and discharging, stress can be effectively dispersed.

[0016] In some embodiments, a plurality of the protrusions are arranged at intervals on the first surface and together form a convex structure; the insulating layer and the convex structure at least partially overlap.

[0017] By defining that the insulating layer and the convex structure at least partially overlap, the convex portion of the current collector can achieve large-area contact with the insulating layer, which provides a further enhancement to the bonding strength between the two.

[0018] In some embodiments, when the protrusions include multiple protrusions, the minimum distance between adjacent protrusions is D1, and D1 satisfies the condition: 0.1mm≤D1≤1mm.

[0019] By setting the distance between adjacent protrusions to between 0.1 mm and 1 mm, within a suitable distance range, the insulating material can fully fill the gaps between the protrusions, providing sufficient contact area to enhance intermolecular forces and effectively improve the bonding strength between the current collector and the insulating layer.

[0020] In some embodiments, the protrusion is integrally formed with the current collector; or, the protrusion is bonded to the surface of the current collector.

[0021] By incorporating protrusions into the current collector or bonding them together, the structural strength and stability of the battery cell can be enhanced.

[0022] In some embodiments, the surface of the current collector facing the insulating layer is a first surface; the first uneven structure includes a plurality of recesses that are recessed into the first surface.

[0023] By including multiple recesses, the surface area of ​​the current collector is increased, enhancing the adhesion between the current collector and the insulation layer, so that the insulation layer is firmly attached to the current collector, reducing the risk of the insulation layer falling off.

[0024] In some embodiments, a plurality of the recesses are arranged at intervals on the first surface and together form a concave structure; the insulating layer and the concave structure at least partially overlap.

[0025] By defining a concave structure composed of multiple recesses that overlaps with the insulating layer, the insulating layer material can be fully filled into the recesses, increasing the intermolecular forces and enhancing the adhesion between the current collector and the insulating layer.

[0026] In some embodiments, when the recess includes multiple recesses, the minimum distance between adjacent recesses is D2, and D2 satisfies the condition: 0.1mm≤D2≤1mm.

[0027] By setting the distance between adjacent recesses to between 0.1 mm and 1 mm, a reasonable distance can ensure that the insulating layer material fully fills the gap between the recesses, thus achieving good mechanical interlocking and providing sufficient contact area to increase intermolecular forces, effectively improving the bonding strength between the two.

[0028] In some embodiments, the recess includes a groove that is integrally formed with the current collector.

[0029] By setting a recess that is integrally formed with the current collector, the groove and the current collector are tightly combined into a whole, thereby enhancing the structural strength and stability of the battery cell.

[0030] In some embodiments, the surface of the current collector facing the insulating layer is a first surface; the first convex-concave structure includes a plurality of protrusions and a plurality of concave portions, the protrusions protruding from the first surface and the concave portions recessed into the first surface, and the plurality of protrusions and the plurality of concave portions are staggered along a first direction.

[0031] By simultaneously setting the protrusions and concave portions in a staggered arrangement, the insulating material can be filled into the concave portions at the same time and closely adhere to the surface of the protrusions, which greatly improves the adhesion between the current collector and the insulating layer and reduces the shedding of the insulating layer. At the same time, the staggered arrangement of the protrusions and concave portions can more effectively disperse stress, reduce the risk of damage to the current collector or insulating layer due to stress concentration, and improve the reliability of the battery cell.

[0032] In some embodiments, along the thickness direction of the current collector, the insulating layer and the active material layer are respectively disposed on both sides of the current collector along its own thickness direction, and the insulating layer is disposed on the outside of the active material layer along the first direction.

[0033] The first concave-convex structure is disposed on both sides of the current collector along its own thickness direction, and is located between the current collector and the insulating layer.

[0034] By setting insulating layers on both sides of the current collector, compared to a single-sided structure, it helps to reduce the peeling of the current collector caused by unilateral force.

[0035] In some embodiments, the insulating layer is located at both ends of the active material layer along the first direction, and the first uneven structure is located at both ends of the current collector along the first direction and at least partially overlaps with the corresponding insulating layer.

[0036] By setting insulating layers at both ends of the active material layer, the active material layer can be constrained and protected, preventing it from falling off from both ends, ensuring the normal progress of the electrochemical reaction, and improving the reliability of the battery cell.

[0037] In some embodiments, the roughness of the surface of the first uneven structure facing the insulating layer is greater than the roughness of the surface of the current collector facing the insulating layer.

[0038] By limiting the roughness of the first uneven structure surface to be greater than the roughness of the current collector surface, the roughness of the first uneven structure surface is greater, increasing the contact area with the insulating layer, thereby improving the adhesion between the insulating layer and the current collector.

[0039] In some embodiments, the dimension of the insulating layer along the first direction is W2, wherein W2 satisfies the condition: 3mm≤W2≤15mm; and / or, the dimension of the insulating layer along its own thickness direction is H2, wherein H2 satisfies the condition: 10μm≤H2≤30μm.

[0040] By limiting the width and thickness of the insulation layer to a suitable range, it is helpful to make the battery structure more compact and improve the space utilization of the battery cells while ensuring the isolation function.

[0041] In some embodiments, a connecting layer is further included, which is disposed between the current collector and the active material layer along the thickness direction of the current collector; wherein, in the direction from the active material layer to the insulating layer, the connecting layer is located between the first concave and convex structures at both ends.

[0042] By setting a connecting layer, the bonding effect between the active material layer and the current collector can be enhanced, effectively reducing the problem of active material layer shedding and improving the reliability of the battery cell.

[0043] In some embodiments, at least one side of the current collector facing the active material layer is provided with a second uneven structure; in the thickness direction, the second uneven structure at least partially overlaps with the active material layer.

[0044] By setting a second concave-convex structure in the current collector facing the active material layer, it helps to increase the contact area between the current collector and the active material layer and improve the adhesion between the current collector and the active material layer.

[0045] In some embodiments, the battery is a cylindrical battery.

[0046] Secondly, this application provides a battery device that includes the battery cell described in the above embodiments.

[0047] When the battery device provided in this application embodiment is used, the insulating layer helps to further isolate the positive and negative electrode plates on top of the separator, reducing the problem of contact between the positive and negative electrode plates caused by the current collector piercing the separator. A first uneven structure is provided on at least one side of the current collector facing the insulating layer, and the first uneven structure at least partially overlaps with the insulating layer. Thus, since the battery undergoes a flattening process and the flattened surface is very close to the edges of the separator and insulating layer, the insulating layer is prone to peeling off in large pieces when wrinkles occur on the outer ring of the battery. The design of the first uneven structure helps to increase the roughness of the current collector surface, thereby increasing the actual contact area between the current collector and the insulating layer, enhancing the adhesion between the insulating layer and the current collector surface, effectively reducing insulation layer peeling, further reducing the risk of high self-discharge caused by the wrinkled current collector piercing the separator, solving the problem of the vehicle not being able to drive well due to large pressure differences, and improving the reliability of the battery cells.

[0048] Thirdly, this application provides an electrical device, including the battery device in the above embodiments, wherein the battery device is used to provide electrical energy.

[0049] When the electrical device provided in this application embodiment is in use, the battery device composed of the battery cells provided in this application embodiment provides electrical energy to the electrical device. Due to the insulating layer, it helps to further isolate the positive and negative electrode plates on top of the separator, reducing the problem of the current collector piercing the separator and causing contact between the positive and negative electrode plates. A first concave-convex structure is provided on at least one side of the current collector facing the insulating layer, and the first concave-convex structure at least partially overlaps with the insulating layer. Thus, since the battery undergoes a flattening process and the flattened surface is very close to the edges of the separator and insulating layer, when wrinkles occur on the outer ring of the battery, the insulating layer is prone to peeling off in large pieces. The design of the first concave-convex structure helps to increase the roughness of the current collector surface, thereby increasing the actual contact area between the current collector and the insulating layer, enhancing the adhesion between the insulating layer and the current collector surface, effectively reducing insulation layer peeling, further reducing the risk of large self-discharge caused by the wrinkled current collector piercing the separator, solving the problem of the vehicle not being able to drive well due to large pressure differences, and improving the reliability of the battery cells.

[0050] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0052] Figure 1 The electrical device provided in some embodiments of this application is a structural schematic diagram of a vehicle.

[0053] Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application.

[0054] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application.

[0055] Figure 4 This is a top view of the electrode in a battery cell provided in some embodiments of this application.

[0056] Figure 5 This is a top view of the electrode in a battery cell provided in some other embodiments of this application.

[0057] Figure 6 This is a top view of the electrode in a battery cell provided in some embodiments of this application.

[0058] Figure 7 This is a schematic cross-sectional view of the current collector surface in a battery cell after the insulating layer has been removed, as provided in some embodiments of this application.

[0059] Figure 8 The electrode in the battery cell provided in some embodiments of this application is Figure 4 The diagram shows a cross-section at point AA.

[0060] Figure 9 for Figure 8 A magnified schematic diagram of the structure at point A in the middle.

[0061] Figure 10 This is a cross-sectional schematic diagram of a battery cell with insulating layers provided on both sides in the thickness direction, provided for other embodiments of this application.

[0062] Figure 11 This is a cross-sectional schematic diagram of the current collector surface in a battery cell after the insulating layer has been removed, provided for some embodiments of this application.

[0063] Figure 12 A cross-sectional schematic diagram showing an insulating layer disposed on the current collector surface in a battery cell according to some embodiments of this application.

[0064] Figure 13 This is a cross-sectional schematic diagram of the current collector surface in a battery cell after the insulating layer has been removed, provided for some embodiments of this application.

[0065] Figure 14 A cross-sectional schematic diagram showing an insulating layer disposed on the current collector surface in a battery cell according to some embodiments of this application.

[0066] Figure 15 This is a cross-sectional schematic diagram of the current collector surface in a battery cell after the insulating layer has been removed, provided for some embodiments of this application.

[0067] Figure 16 A cross-sectional schematic diagram showing an insulating layer disposed on the current collector surface in a battery cell according to some embodiments of this application.

[0068] Figure 17 This is a cross-sectional schematic diagram of the current collector surface in a battery cell after the insulating layer has been removed, provided for some embodiments of this application.

[0069] Figure 18 A cross-sectional schematic diagram showing an insulating layer disposed on the current collector surface in a battery cell according to some embodiments of this application.

[0070] Figure 19 This is a cross-sectional schematic diagram of the current collector in a battery cell provided in some embodiments of this application.

[0071] The reference numerals in the detailed embodiments are as follows:

[0072] 10000 - Vehicles;

[0073] 1000-battery;

[0074] 1100-cell battery;

[0075] 1110 - Electrode assembly; 1120 - Positive electrode top cover; 1130 - Negative electrode top cover; 1140 - Housing; 1150 - Positive electrode tab adhesive; 1160 - Negative electrode tab adhesive; 1170 - Insulating adhesive;

[0076] 100 - Current collector; 110 - Main body; 120 - Electrode;

[0077] 210 - First concave-convex structure; 211 - Convex part; 212 - Concave part; 220 - Second concave-convex structure;

[0078] 300 - Active material layer;

[0079] 400 - Insulation layer;

[0080] 500 - Connection Layer;

[0081] 1200 - Box body; 1210 - Storage space; 1220 - First section; 1230 - Second section;

[0082] 2110 - Controller;

[0083] 3000-motor. Detailed Implementation

[0084] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0085] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0086] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0087] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0088] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0089] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0090] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0091] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0092] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0093] A typical battery cell includes a positive electrode, a separator, and a negative electrode stacked or wound together. The separator is located between the positive and negative electrode. The positive electrode may include a positive current collector and a positive active material, and the negative electrode may include a negative current collector and a negative active material. The separator is a key component used to separate the negative and positive current collectors, preventing them from directly contacting each other and causing a short circuit, while allowing lithium ions to pass freely during charging and discharging.

[0094] When a battery cell is wound, its two ends are subjected to external forces to make its surface flat. The two end faces of the battery cell are close to the edge of the separator. The edge part of the separator (close to the two end faces of the battery) is more likely to bear these mechanical stresses because it does not have the uniform support of the middle area. When the stress exceeds the elastic limit of the separator, the edge of the separator will deform, such as wrinkles. Wrinkles will destroy the integrity and uniformity of the separator, making it easier for the current collector to puncture the separator, thereby causing a short circuit in the contact between the positive and negative electrode plates.

[0095] To address the issue of the separator being easily punctured, the applicant discovered that an insulating layer could be placed between the current collector and the separator to insulate the positive and negative electrode plates, preventing the positive electrode from puncturing the separator and connecting to the negative electrode. However, the applicant also considered that the two end faces of the battery cell are relatively close to the edge of the insulating layer. When wrinkles occur on the outer ring of the battery, the insulating layer is prone to peeling off in pieces. When the insulating layer peels off, the exposed part of the current collector can still easily puncture the separator, thus connecting to the anode and forming a micro-short circuit. This results in high battery self-discharge, which in turn causes a large voltage difference in the entire pack, making it impossible to drive.

[0096] Based on the above considerations, in order to improve the adhesion between the insulating layer and the current collector and solve the problem of easy puncture of the separator, this application provides a battery cell with a first uneven structure on the side of the current collector facing the insulating layer, the first uneven structure at least partially overlapping the insulating layer. This enhances the adhesion between the insulating layer and the current collector surface, effectively reduces insulation layer detachment, and improves the reliability of the battery cell.

[0097] The power batteries manufactured using the battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. Specifically, the electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0098] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0099] Please see Figure 1 , Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0100] Vehicle 10000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Vehicle 10000 has a battery internally installed, which can be located at the bottom, front, or rear of the vehicle. The battery can be used to power vehicle 10000; for example, it can serve as the operating power source for vehicle 10000. Vehicle 10000 may also include a controller and a motor. The controller is used to control the battery to power the motor, for example, to meet the power needs of vehicle 10000 during starting, navigation, and driving.

[0101] In some embodiments of this application, the battery can not only serve as the operating power source for the vehicle 10000, but also as the driving power source for the vehicle 10000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 10000.

[0102] Please see Figure 2 , Figure 2 Exploded views of batteries provided for some embodiments of this application.

[0103] The battery 1000 includes a housing 1200 and battery cells 1100, with the battery cells 1100 housed within the housing 1200. The housing 1200 provides a space for the battery cells 1100 and can have various structures. In some embodiments, the housing 1200 may include a first portion 1220 and a second portion 1230, which overlap each other, and together define a space 1211 for accommodating the battery cells 1100. The second part 1230 can be a hollow structure with one end open, and the first part 1220 can be a plate-like structure. The first part 1220 covers the open side of the second part 1230 so that the first part 1220 and the second part 1230 together define the receiving space 1211. Alternatively, the first part 1220 and the second part 1230 can both be hollow structures with one side open, and the open side of the first part 1220 covers the open side of the second part 1230. Of course, the box 1200 formed by the first part 1220 and the second part 1230 can be of various shapes, such as a cylinder, a cuboid, etc.

[0104] In battery 1000, there can be multiple battery cells 1100. These multiple battery cells 1100 can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 1100 are connected in both series and parallel. Multiple battery cells 1100 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 1100 is housed within a casing 1200. Alternatively, battery 1000 can also be composed of multiple battery cells 1100 first connected in series, parallel, or in a mixed manner to form battery modules, and then these modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within casing 1200. Battery 1000 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 1100.

[0105] Each battery cell 1100 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 1100 can be cylindrical, flat, cuboid, or other shapes.

[0106] Please see Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application. The battery cell 1100 refers to the smallest unit that makes up the battery. Figure 3 The battery cell 1100 includes a casing 1140, a positive electrode top cover 1120, a negative electrode top cover 1130, an electrode assembly 1110, and other functional components.

[0107] The positive electrode top cover 1120 and the negative electrode top cover 1130 are components that cover the opening of the outer casing 1140 to isolate the internal environment of the battery cell 1100 from the external environment. The shapes of the positive electrode top cover 1120 and the negative electrode top cover 1130 can be adapted to the shape of the outer casing 1140 to fit it. The positive electrode top cover 1120 and the negative electrode top cover 1130 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the positive electrode top cover 1120 and the negative electrode top cover 1130 are not easily deformed under compression and impact, giving the battery cell 1100 higher structural strength. Functional components such as electrode terminals can be provided on the positive electrode top cover 1120 and the negative electrode top cover 1130. The electrode terminals can be used to electrically connect to the electrode assembly 1110 for outputting or inputting electrical energy into the battery cell 1100. In some embodiments, the positive electrode top cover 1120 and the negative electrode top cover 1130 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 1100 reaches a threshold. The positive electrode top cover 1120 and the negative electrode top cover 1130 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating structure may also be provided on the inner side of the positive electrode top cover 1120 and the negative electrode top cover 1130. The insulating structure can be used to isolate the electrical connection components inside the housing 1140 from the positive electrode top cover 1120 and the negative electrode top cover 1130 to reduce the risk of short circuit. For example, the insulating structure can be plastic, rubber, etc.

[0108] The outer casing 1140 is a component used to cooperate with the positive electrode top cover 1120 and the negative electrode top cover 1130 to form the internal environment of the battery cell 1100. The formed internal environment can accommodate the electrode assembly 1110, electrolyte, and other components. The outer casing 1140, the positive electrode top cover 1120, and the negative electrode top cover 1130 can be independent components. An opening can be provided on the outer casing 1140, and the positive electrode top cover 1120 and the negative electrode top cover 1130 can be used to close the opening to form the internal environment of the battery cell 1100. Alternatively, the positive electrode top cover 1120, the negative electrode top cover 1130, and the outer casing 1140 can be integrated. Specifically, the positive electrode top cover 1120, the negative electrode top cover 1130, and the outer casing 1140 can form a common connecting surface before other components are inserted into the casing. When it is necessary to encapsulate the interior of the outer casing 1140, the positive electrode top cover 1120 and the negative electrode top cover 1130 are then used to close the outer casing 1140. The outer casing 1140 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the outer casing 1140 can be determined according to the specific shape and size of the electrode assembly 1110. The material of the outer casing 1140 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0109] Electrode assembly 1110 is the component in battery cell 1100 where electrochemical reactions occur. The casing 1140 may contain one or more electrode assemblies 1110. Electrode assembly 1110 mainly consists of a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes, thermally bonded to form a composite strip, and then stacked together. The portions of the positive and negative electrodes containing active material constitute the main body of electrode assembly 1110, while the portions of the positive and negative electrodes without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of battery 1000, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0110] Insulating adhesive 1170 can be provided between the outer wall of the electrode assembly 1110 and the inner wall of the outer casing 1140 to ensure the normal operation and reliability of the electrode assembly 1110. Positive electrode tab adhesive 1150 is provided between the positive electrode top cover 1120 and the electrode assembly 1110, and negative electrode tab adhesive 1160 is provided between the negative electrode top cover 1130 and the electrode assembly 1110. This serves as effective insulation, reducing the risk of short circuits.

[0111] The following section provides a detailed description of the structure of a single battery cell. Please refer to [link / reference needed]. Figures 4-18 , Figure 4 This shows a top view of the electrode in a single battery cell. Figure 5 This shows another top view of the electrode in a single battery cell. Figure 6 This shows another top view of the electrode in a single battery cell. Figure 7 This diagram shows a cross-sectional view of the current collector surface in a single battery cell after the insulating layer has been removed. Figure 8 This shows the electrode in a single battery cell. Figure 4 The cross-sectional diagram at point AA is shown below. Figure 9 It shows Figure 8 A magnified schematic diagram of the structure at point A in the middle. Figure 10 Another cross-sectional schematic diagram of a single battery cell is shown. Figure 11 This diagram shows a cross-sectional view of the current collector surface in another type of battery cell with the insulating layer removed. Figure 12 This diagram shows a cross-sectional view of another type of battery cell in which an insulating layer is disposed on the surface of the current collector. Figure 13 This diagram shows a cross-sectional view of the current collector surface in another type of battery cell with the insulating layer removed. Figure 14 This diagram shows a cross-sectional view of another type of battery cell in which an insulating layer is disposed on the surface of the current collector. Figure 15 This diagram shows a cross-sectional view of the current collector surface in another type of battery cell with the insulating layer removed. Figure 16 This diagram shows a cross-sectional view of another type of battery cell in which an insulating layer is disposed on the surface of the current collector. Figure 17 This diagram shows a cross-sectional view of the current collector surface in another type of battery cell with the insulating layer removed. Figure 18 This shows a cross-sectional schematic diagram of an insulating layer disposed on the surface of the current collector in another type of battery cell; Figure 19 A schematic cross-sectional view of the current collector in a battery cell of some embodiments is shown.

[0112] Please see Figures 3 to 18 This application provides a single battery cell. In this embodiment, the single battery cell 1100 is mainly used as a cylindrical battery for illustration.

[0113] like Figure 3 The battery cell includes a housing 1140 and an electrode assembly 1110. The housing 1140 has a receiving cavity, and the electrode assembly 1110 is disposed in the receiving cavity. The electrode assembly 1110 includes electrode sheets that are stacked or wound.

[0114] It should be noted that stacking refers to laying out and stacking the positive electrode sheet, separator, and negative electrode sheet layer by layer to form a multi-layer stacked structure. After repeating several layers, the whole structure is placed into the receiving cavity of the outer casing 1140. This method is suitable for square or pouch batteries. Winding refers to spirally winding the positive electrode sheet, separator, and negative electrode sheet into a cylindrical or square structure. It generally requires a core support and is wound continuously for many turns before being placed into the outer casing 1140. This method is more suitable for cylindrical batteries. The electrode sheet is long and strip-shaped, and the tabs are usually led out from both ends after winding.

[0115] The electrode assembly 1110 includes a main body portion 110 and an electrode tab portion 120 arranged along a first direction, with the electrode tab portion 120 extending from the main body portion 110 along the first direction. Figure 3 In this context, direction A can be the first direction, which is the direction in which the tab 120 extends.

[0116] like Figure 4 The electrode includes a current collector 100 and an active material layer 300, with the active material layer 300 disposed on one side of the current collector 100 along the thickness direction.

[0117] like Figure 7 , Figure 7 The z-direction is the thickness direction of the current collector 100.

[0118] The current collector 100 serves as the basic structure of the battery cell. It is made of materials with good conductivity, such as copper foil for the negative electrode current collector 100 and aluminum foil for the positive electrode current collector 100. Its main function is to collect and conduct current, and to transmit the current generated by the active material layer 300 to the external circuit.

[0119] The active material layer 300 is a core material participating in the electrochemical reaction of the battery. For example, in lithium-ion batteries, it includes lithium cobalt oxide and lithium nickel cobalt manganese oxide as the positive electrode, and graphite as the negative electrode. The performance of the active material layer 300, such as capacity and charge / discharge efficiency, directly affects the overall performance of the battery.

[0120] During battery charging, lithium ions are extracted from the crystal lattice structure of the positive electrode active material layer and enter the electrolyte. Simultaneously, atoms in the active material layer 300 undergo oxidation, losing electrons, which flow to the negative electrode through the external circuit. Lithium ions migrate towards the negative electrode in the electrolyte and eventually embed themselves into the lattice voids of the negative electrode active material layer (e.g., graphite). At this point, electrical energy is stored in the active material layer, and the battery voltage increases.

[0121] During battery discharge, lithium ions in the negative electrode active material layer are deintercalated into the electrolyte and migrate to the positive electrode. Simultaneously, electrons flow from the negative electrode to the positive electrode through the external circuit, recombine with the lithium ions that have migrated from the electrolyte in the positive electrode active material layer 300, causing a reduction reaction in the atoms of the active material layer 300. With the migration of lithium ions and the flow of electrons, the active material layer 300 releases electrical energy, providing current to the external circuit, and the battery voltage decreases.

[0122] The active material layer 300 can be connected to the current collector 100 by coating. For example, the active material layer 300 can be mixed with additives such as binders and conductive agents to form a uniform slurry. Then, the slurry can be uniformly coated onto the surface of the current collector 100 using a coating device. After drying, rolling, and other processes, the active material layer 300 can be firmly adhered to the current collector 100. Exemplarily, an adhesive can be used to bond the active material layer 300 to the current collector 100. This embodiment does not limit this approach.

[0123] In some embodiments, the active material layer 300 may be disposed on one side of the current collector 100 along the thickness direction z, or the active material layer 300 may be disposed on both sides of the current collector 100. This embodiment does not limit this.

[0124] To improve the insulation effect between the current collector 100 and the diaphragm, please refer to Figures 4 to 6 In some embodiments, the battery cell may further include an insulating layer 400, at least a portion of which is disposed on the outer side of the active material layer 300 along a first direction A. The first direction A is perpendicular to the thickness direction z of the current collector 100 and is the extension direction of the tab portion 120.

[0125] It should be noted that the z-direction perpendicular to the thickness of the current collector 100, i.e., the first direction, can be the width direction of the current collector 100, or the length direction of the current collector 100. The width direction of the current collector 100 can be as follows: Figure 4 and Figure 5 As shown in the x-direction, the length direction of the current collector 100 can be as follows: Figure 4 and Figure 5 Shown in the y direction.

[0126] It should be noted that "at least part of the insulating layer 400 is disposed on the outside of the active material layer 300" means that: along the first direction, the insulating layer 400 may be entirely disposed on the outside of the active material layer 300; or, along the first direction, a portion of the insulating layer 400 may cover the active material layer 300 and extend to the outside of the active material layer 300. This embodiment does not limit this.

[0127] It should be noted that the positional relationship between the insulating layer 400 and the active material layer 300 is not limited. In some embodiments, such as Figure 4 The insulating layer 400 may be disposed on the outside of the active material layer 300 in the width direction x of the current collector 100; or, in some embodiments, such as Figure 5 The insulating layer 400 may be disposed on the outside of the active material layer 300 in the longitudinal direction y of the current collector 100; or, in some embodiments, such as Figure 6 An insulating layer 400 is provided on the outer side of the active material layer 300 in both the length direction (y) and width direction (x) of the current collector 100. This embodiment does not limit this aspect.

[0128] In some embodiments, in the width direction x of the current collector 100, the insulating layer 400 may be located at one end of the active material layer 300; or, the insulating layer 400 may be located at both ends of the active material layer 300. In the length direction y of the current collector 100, the insulating layer 400 may be located at one end of the active material layer 300; or, the insulating layer 400 may be located at both ends of the active material layer 300. This embodiment does not limit this.

[0129] It should be noted that when the cylindrical battery is wound and then flattened, the flattening process is a step in the manufacturing process. After the flattening process, the surface morphology of the battery cell 1100 will change. During the flattening process, the two ends of the battery cell 1100 are subjected to external force to make its surface flat. When the components such as the tab 120 inside the battery cell 1100 are subjected to the flattening force, they will be squeezed and pulled. The bending of the base of the tab 120 will cause the insulating layer 400 at the bending point to fall off, making it easier for the current collector 100 to puncture the separator, thereby causing a short circuit in the contact between the positive and negative electrodes.

[0130] To further improve the adhesion between the insulation layer 400 and the current collector 100, and to reduce the problem of the insulation layer 400 detaching from the surface of the current collector 100 at the bend due to bending at the root of the tab 120, please refer to... Figures 7 to 9 In this embodiment of the application, a first concave-convex structure 210 is provided on the side of the current collector 100 facing the insulating layer 400. In the thickness direction of the current collector 100, the first concave-convex structure 210 at least partially overlaps with the insulating layer 400.

[0131] In some embodiments, the insulating layer 400 may be coated on the surface of the current collector 100. In some embodiments, the insulating layer 400 may be disposed on one side of the current collector 100 along the thickness direction of the current collector 100, or the insulating layer 400 may be disposed on both sides of the current collector 100.

[0132] In some embodiments, at least a portion of the insulating layer 400 may be disposed on the main body portion 110, and at least a portion may be disposed on the tab portion 120. A first uneven structure 210 is provided on the side of the current collector 100 facing the insulating layer 400. For example, the first uneven structure 210 may be located on the side of the main body portion 110 facing the insulating layer 400 to enhance the bonding strength between the insulating layer 400 and the main body portion 110; or, the first uneven structure 210 may be located on the side of the tab portion 120 facing the insulating layer 400 to enhance the bonding strength between the insulating layer 400 and the tab portion 120; or, it may be located on both the side of the main body portion 110 and the side of the tab portion 120 facing the insulating layer 400 to increase the overall bonding strength between the current collector 100 and the insulating layer 400. This embodiment does not limit this, and the specific configuration can be made according to actual needs. In this way, if the base of the tab 120 is bent, it helps to further reduce the risk of the insulation layer 400 easily falling off at the bend and enhances the bonding strength between the insulation layer 400 and the current collector 100.

[0133] It should be noted that the first concave-convex structure 210 and the insulating layer 400 at least partially overlap. This can be understood as the area occupied by the first concave-convex structure 210 and the area occupied by the insulating layer 400 having a common coverage along the first direction.

[0134] "At least partially overlapping" can include the following situations: In some embodiments, a portion of the first convex-concave structure 210 overlaps with a region of the insulating layer 400, while other portions do not overlap with the insulating layer 400. For example, the first convex-concave structure 210 is distributed in a strip shape on the current collector 100, and the insulating layer 400 is also strip-shaped, but their lengths or widths are not exactly the same. In some embodiments, the entire region of the first convex-concave structure 210 completely overlaps with a region of the insulating layer 400, that is, when viewed from a direction perpendicular to the thickness of the current collector 100, their projections are exactly the same. For example, the first convex-concave structure 210 on the current collector 100 is a circular region, and the insulating layer 400 is also a circular region of the same size and position.

[0135] It should be noted that during the process of setting the first uneven structure 210 onto the surface of the current collector 100, the convex portion protrudes beyond the original plane, while the concave portion is recessed into the original plane. This results in the surface no longer being a single smooth surface, but rather forming an undulating shape. The presence of these protrusions and concave portions increases the complexity of the surface's micro-geometry, thereby increasing the surface irregularity and thus increasing the roughness. For example, when processing strip-shaped protrusions or concave portions on the surface of the current collector 100, compared to a flat surface, its geometry is more complex, and the roughness is correspondingly increased.

[0136] In this way, when the insulating layer 400 is connected to the current collector 100, the material of the insulating layer 400 fills the recess and the protrusion is embedded in the insulating layer 400, which increases the contact area and friction between the current collector 100 and the insulating layer 400. The intermolecular forces are also enhanced due to the increased contact area, which greatly improves the adhesion between the two. This reduces the risk that the insulating layer 400 may easily fall off the current collector 100 when the base of the tab 120 is bent during the flattening process of the battery, and further enhances the adhesion strength between the insulating layer 400 and the current collector 100.

[0137] By providing a first uneven structure 210 on the side of the current collector 100 facing the insulating layer 400, the first uneven structure 210 at least partially overlaps with the insulating layer 400. This helps to increase the surface roughness of the current collector 100, thereby increasing the actual contact area between the current collector 100 and the insulating layer 400, enhancing the adhesion between the insulating layer 400 and the surface of the current collector 100, effectively reducing the shedding of the insulating layer 400, further reducing the risk of high self-discharge caused by the wrinkled current collector 100 puncturing the separator, solving the problem of the vehicle not being able to drive well due to large pressure difference, and improving the reliability of the battery cell.

[0138] Please see Figure 8 In some embodiments, along the thickness direction of the current collector 100, the insulating layer 400 completely covers the first convex-concave structure 210 in the orthogonal projection of the current collector 100.

[0139] By setting the first concave-convex structure 210 to completely overlap with the insulating layer 400, the bonding strength between the first concave-convex structure 210 and the insulating layer 400 can be improved, reducing the risk of the insulating layer 400 falling off.

[0140] Please see Figure 8 and Figure 9 In some embodiments, the cross-sectional shape of the first concave-convex structure 210 along the thickness direction may include at least one of strip, arc or square; wherein the extension direction of the first concave-convex structure 210 is the same as the extension direction of the insulating layer 400.

[0141] The cross-sectional shape of the first concave-convex structure 210 is not limited, and can be set according to the actual shape of the insulating layer 400.

[0142] The first uneven structure 210 can be configured in various shapes, providing diverse options for the bonding between the current collector 100 and the insulating layer 400, thus improving flexibility. By ensuring that the extension direction of the first uneven structure 210 is the same as that of the insulating layer 400, the two can fit tightly together along the same direction, working synergistically under stress or during operation. This reduces relative displacement or misalignment caused by inconsistent directions, increases the contact area, and enhances the adhesion between the current collector 100 and the insulating layer 400.

[0143] In some of these embodiments, such as Figures 11 to 14 The first concave-convex structure 210 has an arc-shaped cross-section; in some embodiments, such as Figure 15 and Figure 16 The cross-sectional shape of the first concave-convex structure 210 is strip-shaped.

[0144] Please see Figure 9 In some embodiments, the first concave-convex structure 210 has a dimension of H1 along its own thickness direction, and H1 satisfies the condition: 1μm≤H1≤100μm.

[0145] In some embodiments, the dimension H1 of the first concave-convex structure 210 along its own thickness direction can be 1μm, 10μm, 30μm, 50μm, 70μm, 80μm, 100μm, or any value between 1μm and 100μm. This embodiment does not limit this.

[0146] If the thickness of the first concave-convex structure 210 is less than 1 μm, the first concave-convex structure 210 is too thin overall. The thin first concave-convex structure 210 cannot provide sufficient surface area, the contact area between the current collector 100 and the insulating layer 400 is small, the adhesion is poor, and the insulating layer 400 is easy to fall off from the surface of the current collector 100. If the overall thickness of the first concave-convex structure 210 is greater than 100 μm, the first concave-convex structure 210 is too thick overall, which may lead to excessive rigidity of the structure, and stress concentration is easy to occur when the battery charging and discharging volume changes.

[0147] Therefore, by setting the thickness of the first uneven structure 210 to between 1 μm and 100 μm, the first uneven structure 210 can provide more contact area, thereby increasing the number of contact points between the insulating layer 400 and the current collector 100, which in turn improves the adhesion between the two and enhances the bonding strength.

[0148] In some embodiments, the dimension H1 of the first concave-convex structure 210 along its own thickness direction can satisfy: 5μm≤H1≤30μm, but this embodiment does not limit this.

[0149] Please see Figure 9 In some embodiments, the dimension of the first concave-convex structure 210 along the first direction can be W1, where W1 satisfies the condition: 1mm≤W1≤10mm.

[0150] In some embodiments, the dimension W1 of the first concave-convex structure 210 along the first direction can be 1mm, 3mm, 5mm, 7mm, 8mm, 9mm, 10mm, or any value between 1mm and 10mm. This embodiment does not limit this.

[0151] If the width of the first concave-convex structure 210 is less than 1 mm, the contact area between the first concave-convex structure 210 and the insulating layer 400 is small. Due to the insufficient contact area, the intermolecular attraction between the insulating layer 400 and the current collector 100 cannot be well utilized, the adhesion force is reduced, the adhesion of the insulating layer 400 on the surface of the current collector 100 decreases, and the insulating layer 400 is easy to fall off. If the width of the first concave-convex structure 210 is greater than 10 mm, within the limited battery space, the excessively wide first concave-convex structure 210 will reduce the active material layer 300, and reduce the energy density and capacity of the battery.

[0152] By setting the dimension of the first concave-convex structure 210 along the first direction to between 1 mm and 10 mm, the first concave-convex structure 210 can fully contact the insulating layer 400 within a suitable width range, thereby increasing the contact area and enhancing the adhesion between the current collector 100 and the insulating layer 400.

[0153] In some embodiments, the dimension W1 of the first concave-convex structure 210 along the first direction can satisfy: 2mm≤W1≤8mm. This embodiment does not limit this.

[0154] In some of these embodiments, such as Figure 9 When specifically measuring the minimum thickness H1 of the first concave-convex structure 210, the measurement should be performed perpendicular to the surface of the first concave-convex structure 210, for example from the top of the protruding part to the bottom of the concave part (or in the opposite direction), record the thickness value of each measurement point, and find the minimum value, which is the minimum thickness of the first concave-convex structure.

[0155] In some of these embodiments, such as Figure 9 When specifically measuring the dimension W1 of the first concave-convex structure 210 along the first direction, the measurement should be performed perpendicular to the first direction, from one edge to the other edge, and the width value of each measurement point should be recorded. The minimum value should be found, which is the minimum width of the first concave-convex structure 210.

[0156] Please see Figures 11 to 16 In some embodiments, the surface of the current collector 100 facing the insulating layer 400 is a first surface, and the first uneven structure 210 may include a plurality of protrusions 211, all of which protrude from the first surface.

[0157] In some embodiments, the cross-sectional shape of the protrusion 211 can be strip-shaped, square, or other shapes. Multiple protrusions 211 may have the same shape and maintain consistency within a certain height range, which helps to provide a relatively stable and uniform contact area for the insulating layer 400. This embodiment does not limit this.

[0158] In some embodiments, the multiple protrusions 211 can be arranged according to a certain pattern, such as a square array, a rectangular array, or other arrangements. This embodiment does not limit this. In addition, the number of protrusions 211 is not limited and can be set according to the actual situation.

[0159] In some of these embodiments, such as Figure 11 and Figure 12 The cross-sectional shape of the protrusion 211 is arc-shaped, and multiple protrusions 211 are arranged at intervals; for example Figure 13 and Figure 14 Multiple protrusions 211 are arranged continuously, meaning there are no gaps between adjacent protrusions 211; for example Figure 15 and Figure 16 The cross-sectional shape of the protrusion 211 is strip-shaped, and multiple protrusions 211 are arranged at intervals.

[0160] By setting multiple protrusions 211 arranged at intervals, the multiple protrusions 211 can fully contact the insulating layer 400, thereby enhancing the adhesion between the current collector 100 and the insulating layer 400; at the same time, when the volume changes during the charging and discharging of the battery, stress can be effectively dispersed.

[0161] In some embodiments, along a first direction, a plurality of protrusions 211 are arranged at intervals on a first surface and together form a convex structure; the insulating layer 400 and the convex structure at least partially overlap.

[0162] By defining that the insulating layer 400 and the convex structure at least partially overlap, the convex portion of the current collector 100 can achieve large-area contact with the insulating layer 400, which provides a further enhancement to the bonding strength between the two.

[0163] Please see Figure 11 In some embodiments, when the protrusion 211 includes multiple protrusions, the minimum distance between adjacent protrusions 211 can be D1, where D1 satisfies the condition: 0.1mm≤D1≤1mm.

[0164] If the distance between adjacent protrusions 211 is less than 0.1 mm, the protrusions 211 are too dense, which may cause the insulating layer 400 to not be able to fill the gap between the protrusions 211 well, weakening the mechanical connection and reducing the contact area between the protrusions 211 and the insulating layer 400. If the distance between adjacent protrusions 211 is greater than 1 mm, it will reduce the number of contact points and the contact area between the protrusions 211 and the insulating layer 400. When subjected to external force, the insulating layer 400 is more likely to detach from the surface of the current collector 100, resulting in a decrease in adhesion.

[0165] By setting the distance between adjacent protrusions 211 to between 0.1 mm and 1 mm, within a suitable distance range, the insulating layer 400 material can fully fill the gap between the protrusions 211, providing sufficient contact area to enhance intermolecular forces and effectively improve the bonding strength between the current collector 100 and the insulating layer 400.

[0166] In some embodiments, the minimum distance D1 between adjacent protrusions 211 can satisfy the condition: 0.1mm≤D1≤0.8mm, but this embodiment does not limit this.

[0167] In some embodiments, when measuring the distance between adjacent protrusions 211, it can be the distance between the center line of one protrusion 211 and the center line of the adjacent protrusion 211; or, it can be the distance between the vertex of one protrusion 211 and the vertex of the adjacent protrusion 211. This embodiment does not limit this.

[0168] In some embodiments, the protrusion 211 is integrally formed with the current collector 100; or, the protrusion 211 is bonded to the surface of the current collector 100.

[0169] In some embodiments, the protrusion 211 is integrally formed with the current collector 100, for example, by directly forming the protrusion 211 structure on the raw material used to make the current collector 100 using methods such as stamping, etching, or casting. This helps to improve the reliability and stability of the overall structure.

[0170] In some embodiments, the protrusion 211 can be bonded to the current collector 100, for example by using an adhesive or other bonding method, to fix the protrusion 211 to the surface of the current collector 100, which helps to enhance the structural strength and stability of the battery cell.

[0171] Please see Figure 17 and Figure 18 In some embodiments, the surface of the current collector 100 facing the insulating layer 400 is a first surface, and the first concave-convex structure 210 may include a plurality of recesses 212, all of which are recessed into the first surface.

[0172] In some embodiments, the cross-sectional shape of the recess 212 can be strip-shaped, square, or other shapes. Multiple recesses 212 may have the same shape and maintain consistency within a certain height range, which helps to provide a relatively stable and uniform contact area for the insulating layer 400. This embodiment does not limit this.

[0173] The surface area of ​​the current collector 100 is increased by including multiple recesses 212 arranged at intervals, which enhances the adhesion between the current collector 100 and the insulating layer 400, so that the insulating layer 400 is firmly attached to the current collector 100 and the risk of the insulating layer 400 falling off is reduced.

[0174] Please see Figure 17 and Figure 18 In some embodiments, a plurality of recesses 212 are arranged at intervals on the first surface and together form a recessed structure; the insulating layer 400 and the recessed structure at least partially overlap.

[0175] By defining a concave structure composed of multiple recesses that overlaps with the insulating layer 400, the insulating layer material can be fully filled into the recesses, increasing the intermolecular forces and enhancing the adhesion between the current collector 100 and the insulating layer 400.

[0176] Please see Figure 17 In some embodiments, when the recess 212 includes multiple recesses, the minimum distance between adjacent recesses 212 can be D2, where D2 satisfies the condition: 0.1mm≤D2≤1mm.

[0177] If the distance between adjacent recesses 212 is less than 0.1 mm, the insulating layer 400 may only cover a part of the surface of the recess 212 and cannot penetrate into the interior of the recess 212, thus reducing the actual contact area. If the distance between adjacent recesses 212 is greater than 1 mm, it will reduce the number of contact points and the contact area between the current collector 100 and the insulating layer 400, thereby reducing the adhesion.

[0178] By setting the distance between adjacent recesses 212 to between 0.1 mm and 1 mm, a reasonable distance can ensure that the insulating layer 400 material fully fills the gap between the recesses 212, which not only achieves good mechanical interlocking, but also provides sufficient contact area to increase intermolecular forces and effectively improve the bonding strength between the two.

[0179] In some embodiments, when measuring the distance between adjacent recesses 212, it can be the distance between the center line of one recess 212 and the center line of the adjacent recess 212; or, it can be the distance between the vertex of one recess 212 and the vertex of the adjacent recess 212. This embodiment does not limit this.

[0180] In some embodiments, the recess 212 may include a groove, for example, which may be formed on the current collector 100 by a one-time stamping process. This embodiment is not limited to this.

[0181] The groove and the current collector 100 are integrally formed, so that the groove and the current collector 100 are tightly combined into a whole, which enhances the structural strength and stability of the battery cell.

[0182] In some embodiments, the surface of the current collector 100 facing the insulating layer 400 is a first surface, and the first concave-convex structure includes a plurality of protrusions 211 and a plurality of concave portions 212. The protrusions 211 protrude from the first surface, and the concave portions 212 are recessed into the first surface. Along the first direction, the plurality of protrusions 211 and the plurality of concave portions 212 are staggered.

[0183] It is understandable that "misaligned arrangement" means that in the first direction, the convex part 211 and the concave part 212 are not completely aligned, but are distributed in a staggered manner. That is to say, when observing a certain convex (or concave) on one side of the current collector 100, the corresponding position on the other side of the current collector 100 is not the same convex (or concave) as before, presenting a staggered and non-overlapping arrangement.

[0184] By simultaneously setting the convex and concave portions in a staggered arrangement, the insulating layer material can be filled into the concave portions at the same time and closely adhere to the surface of the convex portions. This significantly improves the adhesion between the current collector 100 and the insulating layer 400, reducing the likelihood of the insulating layer 400 detaching. At the same time, the staggered arrangement of the convex portions 211 and concave portions 212 can more effectively disperse stress, reducing the risk of damage to the current collector 100 or the insulating layer 400 due to stress concentration, and improving the reliability of the battery cell.

[0185] Please see Figure 10 In some embodiments, along the thickness direction of the current collector 100, the insulating layer 400 and the active material layer 300 are respectively disposed on both sides of the current collector 100 along its own thickness direction, and the insulating layer 400 is disposed on the outer side of the active material layer 300 along the first direction; the first concave-convex structure 210 is disposed on both sides of the current collector 100 along its own thickness direction and is located between the current collector 100 and the insulating layer 400.

[0186] By providing insulating layers 400 on both sides of the current collector 100, compared to a single-sided structure, it helps to reduce the peeling of the current collector 100 caused by unilateral force.

[0187] Please see Figure 8 In some embodiments, along a first direction, the insulating layer 400 is located at both ends of the active material layer 300, and the first convex-concave structure 210 is located at both ends of the current collector 100 along the first direction and at least partially overlaps with the corresponding insulating layer 400.

[0188] By setting the insulating layer 400 at both ends of the active material layer 300, the active material layer 300 can be constrained and protected, preventing the active material layer 300 from falling off from both ends, ensuring the normal progress of the electrochemical reaction, and improving the reliability of the battery cell.

[0189] In some embodiments, the surface roughness of the first uneven structure 210 is greater than the surface roughness of the current collector 100.

[0190] Understandably, "roughness" refers to the error in the micro-geometric shape of a material surface, or simply the degree of unevenness of the surface. By limiting the roughness of the surface of the first uneven structure 210 to be greater than the roughness of the surface of the current collector 100, the roughness of the surface of the first uneven structure 210 is greater, increasing the contact area with the insulating layer 400, thereby improving the adhesion between the insulating layer 400 and the current collector 100.

[0191] It should be noted that when testing roughness, for example, the stylus method (contact measurement) can be used, where the instrument's stylus directly contacts the surface being tested, sensing the undulations of the surface's micro-geometry, converting the displacement into an electrical signal, and then processing it to obtain the roughness parameter; alternatively, the optical sectioning method can be used, where the beam of an optical sectioning microscope illuminates the surface being tested, forming a light band tangent to the surface profile, and the roughness parameter is calculated by measuring the curvature of the light band; or, the laser scanning method (non-contact measurement) can be used, where a laser scans the surface being tested, and the height change of the surface profile is calculated through the reflection or scattering signal of the laser beam to obtain the roughness coefficient.

[0192] Please see Figure 9 In some embodiments, the dimension of the insulating layer 400 along the first direction can be W2, and W2 can satisfy the condition: 3mm≤W2≤15mm; the dimension of the insulating layer 400 along its own thickness direction can be H2, and H2 can satisfy the condition: 10μm≤H2≤30μm.

[0193] In some embodiments, the dimension of the insulating layer 400 along the first direction can be 3 mm, 5 mm, 8 mm, 12 mm, 15 mm, or any value between 3 mm and 15 mm. The dimension of the insulating layer 400 along its own thickness direction can be 10 μm, 20 μm, 25 μm, 28 μm, 30 μm, or any value between 10 μm and 30 μm.

[0194] In this embodiment, the dimension of the insulating layer 400 along the first direction can be the width of the insulating layer 400.

[0195] When the width of the insulating layer 400 is too small, it is easily displaced or damaged by external forces. When the width of the insulating layer 400 is too large, it will occupy too much internal space of the battery. When the thickness of the insulating layer 400 is too small, it may be punctured or damaged in an electrochemical environment, resulting in contact between the positive and negative electrodes. When the thickness of the insulating layer 400 is too large, it will increase the path length of ion transport and reduce ion conduction efficiency.

[0196] By limiting the width and thickness of the insulating layer 400 to a suitable range, it helps to make the battery structure more compact and improve the space utilization of the battery cells while ensuring the isolation function.

[0197] Please see Figure 8 In some embodiments, the electrode may further include a connecting layer 500, which is disposed between the current collector 100 and the active material layer 300 along the thickness direction of the current collector 100; the connecting layer 500 is located between the first concave and convex structures 210 at both ends in the direction from the active material layer 300 to the insulating layer 400.

[0198] In some of these embodiments, such as Figure 8 In the thickness direction of the current collector 100, the connecting layer 500 can be disposed on one side of the current collector 100, or, as... Figure 10 The connecting layer 500 can be disposed on both sides of the current collector 100.

[0199] By setting the connecting layer 500, since the connecting layer 500 at least partially overlaps with the active material layer 300, it can provide more contact points and a larger contact area, allowing the active material to adhere better to the current collector 100, enhancing the bonding effect between the active material layer 300 and the current collector 100, reducing the active material layer 300 from falling off the surface of the current collector 100, and improving the reliability of the battery cell.

[0200] In some embodiments, the connecting layer 500 may include a conductive agent, a dispersant and a binder, wherein the mass ratio of the conductive agent, the dispersant and the binder is (55-65): (1-10): (30-40).

[0201] In some embodiments, the content of the conductive agent can be 55%, 57%, 60%, 65%, or any value between 55% and 65%. This embodiment primarily uses a conductive agent content of 60% as an example. The high proportion of the conductive agent in the mass ratio ensures that the connecting layer 500 has good conductivity, improves electron conduction efficiency, and thus enables the battery cells to quickly and stably transmit current during charging and discharging, thereby improving the battery's charging and discharging efficiency and power performance.

[0202] In some embodiments, the conductive agent may include one of conductive agent sp, KS-6, conductive graphite, carbon nanotubes, and graphene. In this embodiment, conductive agent sp is mainly used as an example of the above-mentioned conductive agent for illustration.

[0203] In some embodiments, the content of the dispersant can be 1%, 3%, 5%, 10%, or any value between 1% and 10%. In this embodiment, the dispersant content is mainly described as 5%. The relatively small mass percentage of the dispersant ensures that the conductivity and adhesion of the bonding layer 500 are not affected, while also allowing the conductive agent to be uniformly dispersed in the coating system, reducing the agglomeration of conductive agent particles and minimizing performance differences between batteries.

[0204] In some embodiments, the dispersant may include at least one of sodium carboxymethyl cellulose (CMC-Na), methylcellulose, and ethylcellulose. In this embodiment, sodium carboxymethyl cellulose (CMC-Na) is used as an example of the dispersant.

[0205] In some embodiments, the adhesive content can be 30%, 32%, 35%, 40%, or any value between 30% and 40%. This embodiment primarily uses an adhesive content of 30% as an example. The appropriate mass percentage of adhesive ensures sufficient adhesion between the bonding layer 500 and the current collector 100.

[0206] In some embodiments, the binder may be at least one of styrene-butadiene rubber (SBR), polyacrylate, ethylene propylene rubber, nitrile rubber, and polyvinylidene fluoride (PVDF). In this embodiment, styrene-butadiene rubber (SBR) is mainly used as an example for illustration.

[0207] By adopting the above-mentioned formula, while enhancing the adhesion between the current collector 100 and the active material layer 300, its own conductivity can provide a good conductive path between the current collector 100 and the active material layer 300, reduce the obstruction in the electron transport process, and thus improve the charging and discharging efficiency of the battery.

[0208] In some embodiments, the connecting layer 500 may include an active material, a conductive agent, a binder, and an auxiliary agent, wherein the mass ratio of the active material, the conductive agent, the binder, and the auxiliary agent is (95-98): (0.4-0.8): (1.5-2.0): (0.1-0.5).

[0209] In some embodiments, the content of the active material can be 95%, 96%, 97%, 97.3%, 98%, or any value between 95% and 98%. This embodiment primarily uses an active material content of 97.3% as an example. The higher proportion of active material by mass allows the battery to store more lithium ions per unit mass or unit volume, thereby significantly improving the battery's energy density.

[0210] In some embodiments, the active material may be one of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, and lithium manganese cobalt oxide.

[0211] In some embodiments, the content of the conductive agent can be 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or any value between 0.4% and 0.8%. This embodiment primarily uses a conductive agent content of 0.6% as an example. In some embodiments, the conductive agent may include one of conductive agent sp, KS-6, conductive graphite, carbon nanotubes, and graphene. Although the proportion of the conductive agent is relatively small, it can construct an effective conductive network between the active material particles, reduce the resistance of the active material layer 300, and improve the electron conduction efficiency.

[0212] In some embodiments, the binder content can be 1.5%, 1.6%, 1.7%, 1.8%, 2.0%, or any value between 1.5% and 2.0%. This embodiment primarily uses a binder content of 1.8% as an example. In some embodiments, the binder can be at least one of styrene-butadiene rubber (SBR), polyacrylate, ethylene propylene rubber, nitrile rubber, and polyvinylidene fluoride (PVDF). The binder content is controlled within a suitable range to provide sufficient adhesion to the active material layer 300, ensuring a tight bond between the active material particles and the conductive agent, and firm attachment to the current collector 100.

[0213] In some embodiments, the content of the auxiliary agent can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any value between 0.1% and 0.5%. This embodiment primarily uses an auxiliary agent content of 0.3% as an example. In some embodiments, the auxiliary agent can be a fluorosurfactant (FS-1), which can significantly reduce the surface tension of the aqueous solution, improve the wetting and penetration of the electrolyte into electrode materials, battery separators, etc., allowing the electrolyte to better contact with other components, promoting lithium-ion transport, and contributing to improved battery performance.

[0214] By adopting the above-mentioned formula, the connecting layer 500, which originally played a role in connecting and enhancing adhesion, is set as an active material layer. The active material layer also assumes the function of the connecting layer 500. The connecting layer 500 can directly participate in the electrochemical reaction of the battery and directly contact the current collector 100, which can more effectively promote the electrochemical reaction and improve the charging and discharging performance of the battery.

[0215] Please see Figure 19 In some embodiments, at least one side of the current collector 100 facing the active material layer 300 may be provided with a second concave-convex structure 220, which is a conductive structure; in the direction perpendicular to the thickness of the current collector 100, the second concave-convex structure 220 at least partially overlaps with the active material layer 300.

[0216] By providing a second concave-convex structure 220 on the current collector 100 facing the active material layer 300, it helps to increase the contact area between the current collector 100 and the active material layer 300, and improve the adhesion between the current collector 100 and the active material layer 300; at the same time, by providing the second concave-convex structure 220 as a conductive structure, the electron transport path is smoother, which is beneficial to improving the charging and discharging efficiency of the battery cell.

[0217] The battery cell provided in this application embodiment includes a current collector 100. An active material layer 300 and an insulating layer 400 are disposed on one side along the thickness direction of the current collector 100. At least a portion of the insulating layer 400 is disposed on at least a portion of the outer periphery of the active material layer 300 along a first direction. A first uneven structure 210 is provided on the side of the main body 110 of the current collector 100 facing the insulating layer 400. In the extension direction of the tab portion 120, the first uneven structure 210 at least partially overlaps with the insulating layer 400. Specifically, in the direction perpendicular to the thickness of the current collector 100, the first uneven structure 210 completely overlaps with the insulating layer 400. In this embodiment, the cross-sectional shape of the first uneven structure 210 along the direction perpendicular to the first direction includes at least one of strip, arc, or square. The surface of the current collector 100 facing the insulating layer 400 is the first surface. When the first uneven structure 210 consists of multiple protrusions 211, the protrusions 211 protrude from the first surface, and the insulating layer 400 is coated on the surface of the protrusions 211. When the first uneven structure 210 consists of multiple recesses 212, the recesses 212 are recessed into the first surface, and the insulating layer 400 is coated in the recesses 212. When an uneven substrate is used below the insulating layer 400, the dimension of the insulating layer 400 along the first direction satisfies 3mm≤W2≤15mm, and the dimension of the insulating layer 400 along its own thickness direction satisfies 10μm≤H2≤30μm.

[0218] When the battery cell provided in this application embodiment is manufactured, by setting an insulating layer 400 on the current collector 100, it helps to further isolate the positive and negative electrode plates on the basis of the separator, reducing the problem of the current collector 100 piercing the separator and causing the positive and negative electrode plates to come into contact. By providing a first concave-convex structure 210 on the side of the current collector 100 facing the insulating layer 400, the first concave-convex structure 210 at least partially overlaps with the insulating layer 400 in the thickness direction of the current collector 100. In this way, since the battery undergoes a flattening process and the flattened surface is very close to the edge of the separator and the insulating layer 400, the insulating layer 400 is prone to peeling off in pieces when wrinkles occur on the outer ring of the battery. The design of the first concave-convex structure 210 helps to increase the surface roughness of the current collector 100, thereby increasing the contact area between the current collector 100 and the insulating layer 400, enhancing the adhesion between the insulating layer 400 and the surface of the current collector 100, effectively reducing the peeling off of the insulating layer 400, further reducing the risk of large self-discharge caused by the wrinkled current collector 100 puncturing the separator, solving the problem of the whole vehicle not being able to drive well due to large pressure difference, and improving the reliability of the battery cell. By ensuring the first uneven structure 210 completely overlaps with the insulating layer 400, the uneven surface of the current collector 100 and the insulating layer 400 are tightly bonded from all directions, significantly improving the adhesion between them. By providing various shapes of the first uneven structure 210, diverse options are available for the bonding between the current collector 100 and the insulating layer 400, increasing flexibility. By configuring the first uneven structure 210 as multiple protrusions 211, which protrude from the surface of the current collector 100, and coating the surface of the protrusions 211 with the insulating layer 400, the adhesion between the current collector 100 and the insulating layer 400 is enhanced. By configuring the first uneven structure 210 as multiple recesses 212, the insulating layer 400 is firmly attached to the current collector 100, reducing the risk of the insulating layer 400 detaching. By setting the width of the insulating layer 400 to satisfy 3mm≤W2≤15mm and the thickness of the insulating layer 400 to satisfy 10μm≤H2≤30μm, it helps to make the battery structure more compact and improve the space utilization of the battery cell while ensuring the isolation function.

[0219] Please see Figure 2 This application also provides a battery device, which includes a housing 1200 and a battery cell 1100, wherein the battery cell 1100 is housed within the housing 1200.

[0220] When the battery device provided in this application embodiment is used, the insulating layer 400 helps to further isolate the positive and negative electrode plates on the basis of the separator, reducing the problem of the current collector 100 piercing the separator and causing the positive and negative electrode plates to come into contact; by providing a first concave-convex structure 210 on at least one side of the current collector 100 facing the insulating layer 400, the first concave-convex structure 210 at least partially overlaps with the insulating layer 400. Thus, because the battery undergoes a flattening process and the flattened surface is very close to the edge of the separator and the insulating layer 400, the insulating layer 400 is prone to peeling off in large pieces when wrinkles occur on the outer ring of the battery. The design of the first concave-convex structure 210 helps to increase the surface roughness of the current collector 100, thereby increasing the actual contact area between the current collector 100 and the insulating layer 400, enhancing the adhesion between the insulating layer 400 and the surface of the current collector 100, effectively reducing the peeling off of the insulating layer 400, further reducing the risk of large self-discharge caused by the wrinkled current collector 100 puncturing the separator, solving the problem that the whole vehicle cannot drive well due to large pressure difference, and improving the reliability of the battery cell.

[0221] Please see Figure 1 This application also provides an electrical device, including the battery device of any of the above embodiments, the battery device being used to provide electrical energy to the electrical device.

[0222] When the electrical device provided in this application embodiment is in use, the battery device composed of the battery cells 1100 provided in this application embodiment provides electrical energy to the electrical device. The insulating layer 400 helps to further isolate the positive and negative electrode plates on top of the separator, reducing the problem of the current collector 100 piercing the separator and causing contact between the positive and negative electrode plates; a first uneven structure 210 is provided on at least one side of the current collector 100 facing the insulating layer 400, and the first uneven structure 210 at least partially overlaps with the insulating layer 400. Thus, because the battery undergoes a flattening process and the flattened surface is very close to the edge of the separator and the insulating layer 400, the insulating layer 400 is prone to peeling off in large pieces when wrinkles occur on the outer ring of the battery. The design of the first concave-convex structure 210 helps to increase the surface roughness of the current collector 100, thereby increasing the actual contact area between the current collector 100 and the insulating layer 400, enhancing the adhesion between the insulating layer 400 and the surface of the current collector 100, effectively reducing the peeling off of the insulating layer 400, further reducing the risk of large self-discharge caused by the wrinkled current collector 100 puncturing the separator, solving the problem that the whole vehicle cannot drive well due to large pressure difference, and improving the reliability of the battery cell.

[0223] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The outer casing (1140) has a receiving cavity; Electrode assembly (1110), disposed in the receiving cavity, the electrode assembly (1110) includes stacked or wound electrode sheets, the electrode sheets comprising: The current collector (100) includes a main body portion (110) and an electrode portion (120) arranged along a first direction, the electrode portion (120) extending from the main body portion (110) along the first direction; An active material layer (300) is disposed on one side of the main body (110) in the thickness direction; An insulating layer (400) is disposed at least partially on the outside of the active material layer (300) along the first direction, which is perpendicular to the thickness direction of the current collector (100). The current collector (100) has a first concave-convex structure (210) on the side facing the insulating layer (400), and in the thickness direction, the first concave-convex structure (210) at least partially overlaps with the insulating layer (400).

2. The battery cell according to claim 1, characterized in that, Along the thickness direction, the insulating layer (400) completely covers the first uneven structure (210) in the orthogonal projection of the current collector (100).

3. The battery cell according to claim 1, characterized in that, The cross-sectional shape of the first concave-convex structure (210) along the thickness direction includes at least one of strip shape, arc shape or square shape; The first concave-convex structure (210) extends in the same direction as the insulating layer (400).

4. The battery cell according to claim 1, characterized in that, The first concave-convex structure (210) has a dimension H1 along its own thickness direction, and H1 satisfies the following condition: 1μm≤H1≤100μm.

5. The battery cell according to claim 1, characterized in that, The dimension of the first concave-convex structure (210) along the first direction is W1, and W1 satisfies the condition: 1mm≤W1≤10mm.

6. The battery cell according to any one of claims 1-5, characterized in that, The surface of the current collector (100) facing the insulating layer (400) is the first surface; The first concave-convex structure (210) includes a plurality of protrusions (211), which protrude from the first surface.

7. The battery cell according to claim 6, characterized in that, The plurality of protrusions (211) are arranged at intervals on the first surface and together form a convex structure; the insulating layer (400) and the convex structure at least partially overlap.

8. The battery cell according to claim 7, characterized in that, When there are multiple protrusions (211), the minimum distance between adjacent protrusions (211) is D1, and D1 satisfies the following condition: 0.1mm≤D1≤1mm.

9. The battery cell according to claim 8, characterized in that, The protrusion (211) is integrally formed with the current collector (100); or, the protrusion (211) is bonded to the first surface.

10. The battery cell according to any one of claims 1-5, characterized in that, The surface of the current collector (100) facing the insulating layer (400) is the first surface; The first concave-convex structure (210) includes a plurality of recesses (212) that are recessed into the first surface.

11. The battery cell according to claim 10, characterized in that, The plurality of recesses (212) are arranged at intervals on the first surface and together form a concave structure; the insulating layer (400) and the concave structure at least partially overlap.

12. The battery cell according to claim 11, characterized in that, When there are multiple recesses (212), the minimum distance between adjacent recesses (212) is D2, and D2 satisfies the following condition: 0.1mm≤D2≤1mm.

13. The battery cell according to claim 12, characterized in that, The recess (212) includes a groove, which is integrally formed with the current collector (100).

14. The battery cell according to any one of claims 1-5, characterized in that, The surface of the current collector (100) facing the insulating layer (400) is the first surface; The first concave-convex structure includes a plurality of protrusions (211) and a plurality of concave portions (212). The protrusions (211) protrude from the first surface, and the concave portions (212) are recessed into the first surface. Along the first direction, the plurality of protrusions (211) and the plurality of concave portions (212) are staggered.

15. The battery cell according to any one of claims 1-5, characterized in that, Along the thickness direction of the current collector (100); The insulating layer (400) and the active material layer (300) are respectively disposed on both sides of the current collector (100) along its own thickness direction, and the insulating layer (400) is disposed on the outside of the active material layer (300) along the first direction. The first concave-convex structure (210) is disposed on both sides of the current collector (100) along its own thickness direction, and is located between the current collector (100) and the insulating layer (400).

16. The battery cell according to any one of claims 1-5, characterized in that, The insulating layer (400) is located at both ends of the active material layer (300) along the first direction, and the first uneven structure (210) is located at both ends of the current collector (100) along the first direction and at least partially overlaps with the corresponding insulating layer (400).

17. The battery cell according to any one of claims 1-5, characterized in that, The surface roughness of the first uneven structure (210) facing the insulating layer (400) is greater than the surface roughness of the current collector (100) facing the insulating layer (400).

18. The battery cell according to any one of claims 1-5, characterized in that, The dimension of the insulating layer (400) along the first direction is W2, and W2 satisfies the condition: 3mm≤W2≤15mm; And / or, the dimension of the insulating layer (400) along its own thickness direction is H2, wherein H2 satisfies the condition: 10μm≤H2≤30μm.

19. The battery cell according to any one of claims 1-5, characterized in that, The electrode further includes a connecting layer (500), which is disposed between the current collector (100) and the active material layer (300) along the thickness direction of the current collector (100). In this case, the connecting layer (500) is located between the first concave-convex structures (210) at both ends, in the direction from the active material layer (300) to the insulating layer (400).

20. The battery cell according to any one of claims 1-5, characterized in that, The current collector (100) has a second concave-convex structure (220) on at least one side facing the active material layer (300). In the thickness direction, the second convex-concave structure (220) at least partially overlaps with the active material layer (300).

21. The battery cell according to any one of claims 1-5, characterized in that, The battery is a cylindrical battery.

22. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-21.

23. An electrical appliance, characterized in that, Includes the battery device of claim 22, the battery device being used to provide electrical energy.

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