Battery cell and method of manufacturing the same, battery device, and electric device

Abstract

The application discloses a battery cell, a manufacturing method thereof, a battery device and a power utilization device. The battery cell comprises a first pole piece, the first pole piece comprises a current collector and a film layer, and the film layer is arranged on at least one side of the current collector in the thickness direction. The film layer comprises a first film layer and a second film layer, at least part of the first film layer is located between the second film layer and the current collector in the thickness direction of the current collector, the first film layer has a first non-flat edge in a first direction, the first non-flat edge comprises first convex parts and first concave parts arranged alternately in a second direction, the first direction, the second direction and the thickness direction are perpendicular to each other, the second film layer has a second non-flat edge in the first direction, the second non-flat edge is arranged on the same side as the first non-flat edge, and the second non-flat edge comprises second convex parts and second concave parts arranged alternately in the second direction. The technical scheme provided by the application can improve the yield and reliability of the battery device.

Description

Technical Field

[0001] This application relates to the technical field, and more specifically, to a battery cell and its manufacturing method, a battery device, and an electrical device. Background Technology

[0002] Battery devices are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery technology, how to improve the yield and reliability of battery devices is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] This application provides a battery cell and its manufacturing method, a battery device, and an electrical device. The technical solution provided by this application can improve the yield and reliability of the battery device.

[0005] This application is achieved through the following technical solution: In a first aspect, some embodiments of this application provide a battery cell, the battery cell including a first electrode, the first electrode including a current collector and a film layer, the film layer being disposed on at least one side in the thickness direction of the current collector. The film layer includes a first film layer and a second film layer, along the thickness direction of the current collector, at least a portion of the first film layer being located between the second film layer and the current collector, the first film layer having a first non-straight edge in a first direction, the first non-straight edge including a first protrusion and a first concave portion alternately arranged along a second direction, the first direction, the second direction and the thickness direction being perpendicular to each other, the second film layer having a second non-straight edge in the first direction, the second non-straight edge being disposed on the same side as the first non-straight edge, the second non-straight edge including a second protrusion and a second concave portion alternately arranged along the second direction.

[0006] In the battery cell provided above, the first film layer has a first non-straight edge in the first direction, and the first non-straight edge is partially concave, so that the first film layer has first protrusions and first concave portions arranged alternately along the second direction. On the one hand, during the manufacturing process of the battery cell, the concave area of ​​the first film layer can provide a space for the active material that migrates in the first direction due to external force (such as roller pressure), improve the edge thickness uniformity of the film layer in the first direction, reduce the problem of poor welding due to inconsistent root thickness during tab welding, and enable the battery cell to have a higher yield and reliability. On the other hand, after the battery cell has undergone a certain number of charge and discharge cycles, the concave area of ​​the first film layer can provide a space for the active material that migrates in the first direction due to expansion, reduce the amount of expansion of the film layer in the first direction, thereby reducing the risk of cracking at the welding joint between the tab and the current collector due to excessive expansion of the active material, enabling the battery cell to have higher reliability, and thus enabling the battery device to have higher reliability. Meanwhile, the second film layer has a second non-straight edge in the first direction, and the second non-straight edge is locally concave, so that the edge of the second film layer forms a second convex part and a second concave part arranged alternately along the second direction. This can effectively accommodate the active material that migrates to the first direction due to external force or internal expansion force, improve the problem of inconsistent film layer edge thickness or excessive film layer expansion along the first direction, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0007] According to some embodiments of this application, the outline of the first protrusion is triangular, arc-shaped, or trapezoidal.

[0008] In the above solution, by setting the outline of the first protrusion to a triangle, arc, or trapezoid, the concave areas on both sides of the first protrusion effectively provide a space for the active material that migrates in the film layer due to external force or expansion force, thereby improving the problem of inconsistent film layer edge thickness or excessive expansion of the film layer along the first direction, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0009] According to some embodiments of this application, the first non-straight edge includes a plurality of first protrusions and a plurality of first recesses.

[0010] In the above scheme, the first non-straight edge of the first film layer forms a plurality of first protrusions and a plurality of first concave portions arranged alternately along the second direction, which can provide multiple accommodating spaces for the active material, effectively improving the problem of inconsistent thickness at the edge of the film layer or excessive expansion of the active material layer along the first direction, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0011] According to some embodiments of this application, a plurality of first protrusions are arranged continuously or spaced apart along a second direction.

[0012] In the above scheme, by arranging the multiple first protrusions in a continuous manner, the coating cycle of the first active material layer can be effectively improved, which is beneficial to improving the manufacturing efficiency of the battery cell. By arranging the multiple first protrusions in a spaced manner, the risk of film cracking caused by stress concentration due to sharp corners between the first protrusions and first recesses can be reduced, which is beneficial to improving the reliability of the battery cell.

[0013] According to some embodiments of this application, along the second direction, the distance between two adjacent first protrusions and the distance between two adjacent second protrusions are different.

[0014] In the above scheme, by setting the spacing of the first protrusion to be different from the spacing of the second protrusion, the first protrusion and the second concave can at least partially overlap. The first concave and the first protrusion at least partially overlap, which on the one hand can increase the connection area between the first non-straight edge and the second non-straight edge, which is beneficial to improving the structural stability of the film layer. On the other hand, it allows the active material to migrate to the thinner part between the first film layer and the second film layer when subjected to external force or expansion force, thereby making the thickness uniformity of the edge part of the film layer high and the expansion degree of the film layer in the first direction low, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0015] According to some embodiments of this application, the first protrusion and the second protrusion are misaligned along the second direction.

[0016] In the above scheme, by misaligning the first convex part and the second convex part along the second direction, the first convex part is located in the second concave part, and the second convex part is located in the first concave part. On the one hand, this can increase the connection area between the first non-straight edge and the second non-straight edge, which is beneficial to improving the structural stability of the film layer. On the other hand, it can cause the active material to migrate to the thinner part between the first film layer and the second film layer when subjected to external force or expansion force, thereby making the thickness uniformity of the edge part of the film layer high and the expansion degree of the film layer in the first direction low, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0017] According to some embodiments of this application, along the first direction, the maximum dimension L of the first protrusion satisfies: 0.5mm≤L≤3mm.

[0018] In the above scheme, the maximum size of the first protrusion is greater than or equal to 0.5 mm, which can provide a larger accommodation space for the migration of the film layer along the first direction, improve the problem of inconsistent film layer edge thickness or excessive film layer expansion along the first direction, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability; the maximum size of the first protrusion is less than or equal to 3 mm, which can reduce the risk of a decrease in the amount of active material caused by the excessive size of the first protrusion, resulting in a decrease in the energy density of the battery cell, so that the battery cell has a high energy density.

[0019] According to some embodiments of this application, along a first direction, at least a portion of the first film layer extends beyond the second film layer.

[0020] In the above scheme, by setting at least a portion of the first film layer to extend beyond the second film layer, the first film layer can effectively support the second film layer, and the film layer forms a transition region with gradually decreasing thickness along the edge of the first direction. When the film layer migrates in the first direction under external force or internal expansion force, it can fill the thickness of the transition region, resulting in high uniformity of thickness of the entire first electrode sheet, which is beneficial to improving the yield and reliability of battery cells, and thus to improving the yield and reliability of battery devices.

[0021] According to some embodiments of this application, along a first direction, the second film layer extends beyond the first recess.

[0022] In the above scheme, the second film layer can be located in the concave area of ​​the first film layer, which can make the thickness of the edge of the film layer transition smoothly. When the second film layer is subjected to external force or internal expansion force, it can effectively guide the active material of the second film layer to fill the concave area of ​​the first film layer, thereby improving the problem of inconsistent thickness at the edge of the film layer or excessive expansion of the film layer along the first direction, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0023] According to some embodiments of this application, a portion of the first protrusion is located between the second film layer and the current collector, and another portion of the first protrusion extends beyond the second film layer along a first direction.

[0024] In the above scheme, a portion of the first protrusion is sandwiched between the second film layer and the current collector, which can improve the structural stability of the edge portion of the first film layer and reduce the risk of the edge portion of the first film layer falling off from the current collector. The other portion of the first protrusion extends beyond the second film layer, which can effectively accommodate the active material of the second film layer that migrates in the first direction due to external force or internal expansion force, so that the battery cell has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0025] According to some embodiments of this application, the first electrode is a negative electrode, the first film layer is a first active material layer, and the second film layer is a second active material layer.

[0026] According to some embodiments of this application, the coefficient of expansion of the first active material layer is smaller than that of the second active material layer.

[0027] In the above scheme, the first active material layer has a small coefficient of expansion, which can provide stable support for the upper second active material layer, effectively absorb and buffer the expansion stress from the second active material layer, and prevent the current collector from wrinkling or being damaged. Furthermore, by forming a first non-straight edge at the edge of the first active material layer, it can effectively accommodate active material migrating from the second active material layer due to external forces or expansion forces, resulting in higher yield and reliability for the battery cells, and consequently, higher yield and reliability for the battery device.

[0028] According to some embodiments of this application, the material of the first active material layer includes graphite, and the material of the second active material layer includes a silicon-carbon composite material.

[0029] In the above scheme, the first active material layer includes graphite. Utilizing the characteristics of graphite's small expansion and excellent adhesion to the current collector, it provides a robust support platform for the second active material layer, effectively absorbing and buffering the expansion stress from the second active material layer and preventing wrinkling or damage to the current collector. The second active material layer includes a high-specific-capacity silicon-carbon composite material, which can effectively improve the energy density of the battery cell. To this end, the support of the lower graphite layer restricts most of the expansion of the silicon-carbon composite material to the vertical direction, rather than the horizontal direction, thereby significantly reducing the overall lateral stress of the active material layer, improving structural integrity, and enabling the battery cell to have a higher energy density.

[0030] According to some embodiments of this application, the mass of the first active material layer is greater than the mass of the second active material layer.

[0031] In the above scheme, by setting the mass of the first active material layer to be greater than that of the second active material layer, on the one hand, the first active material layer can provide stable support for the second active material layer, and on the other hand, it can ensure the low internal resistance of the negative electrode to a certain extent, so that the battery cell has a high charge and discharge rate.

[0032] According to some embodiments of this application, the mass ratio of the first active material layer to the second active material layer is greater than 1 and less than 9.

[0033] According to some embodiments of this application, the first electrode is a positive electrode, the first film layer includes a third active material layer and a first insulating layer that are interconnected, the first insulating layer and the third active material layer are arranged along the first direction, the first insulating layer has a first non-straight edge, and the second film layer includes a fourth active material layer.

[0034] In the battery cell provided above, the first electrode is a positive electrode, which improves the overall performance of the battery cell through the synergistic effect of the third and fourth active material layers. The side of the first insulating layer away from the third active material layer is locally concave, so that the side of the first insulating layer away from the third active material layer forms a first convex portion and a first concave portion arranged alternately along the second direction. On the one hand, during the manufacturing process of a battery cell, the concave area of ​​the first insulating layer provides space for the third and fourth active material layers and the active material that migrates in the first direction due to external forces (such as roller pressure) on the first insulating layer. This ensures uniform thickness at the edge of the entire positive electrode sheet in the first direction, reducing the problem of incomplete welding due to inconsistent thickness at the root during positive electrode tab welding. This results in a higher yield and reliability for the battery cell. On the other hand, after a certain number of charge-discharge cycles, the concave area of ​​the first insulating layer provides space for the active material that migrates in the first direction due to expansion of the third and fourth active material layers. This reduces the amount of expansion of the active material in the first direction, thereby reducing the risk of cracking at the welding point between the positive electrode tab and the current collector due to excessive expansion of the active material. This results in higher reliability for the battery cell, and consequently, higher reliability for the battery device.

[0035] According to some embodiments of this application, the second film layer includes a second insulating layer connected to a fourth active material layer. Along the thickness direction, a third active material layer is located between the fourth active material layer and the current collector, and at least a portion of the first insulating layer is located between the second insulating layer and the current collector.

[0036] In the above scheme, by providing a second insulating layer on one side of the fourth active material layer along the first direction, and with at least a portion of the first insulating layer located between the second insulating layer and the current collector, the connection stability between the first insulating layer and the current collector can be high. This allows the recessed area of ​​the first insulating layer to effectively provide a space for the active materials of the third and fourth active material layers to migrate in the first direction due to external force or expansion, which is beneficial to improving the reliability of the battery cell and thus the reliability of the battery device.

[0037] According to some embodiments of this application, the coefficient of expansion of the third active material layer is greater than that of the fourth active material layer.

[0038] According to some embodiments of this application, the active material of the third active material layer includes ternary materials, and the active material of the fourth active material layer includes lithium iron phosphate.

[0039] In the above scheme, the third active material layer is an energy layer with high active material energy density, and the fourth active material layer is a safety layer with stable active material structure, which can effectively reduce the risk of thermal runaway.

[0040] According to some embodiments of this application, the mass of the fourth active material layer is greater than the mass of the third active material layer.

[0041] In the above scheme, by setting the mass of the third active material layer to be less than that of the fourth active material layer, the fourth active material layer effectively acts as a safety layer, which is beneficial to improving the reliability of the battery cell.

[0042] According to some embodiments of this application, the mass ratio of the fourth active material layer to the mass ratio of the third active material layer is greater than 1 and less than 9.

[0043] According to some embodiments of this application, the battery cell is a right parallelepiped, and includes a current collector and an electrode assembly. The electrode assembly includes a first electrode plate, and the current collector includes a body and at least one first tab. The body has a third edge in a first direction, and at least one first tab extends from the third edge. The first tab is electrically connected to the current collector. The first film layer includes a first portion and a second portion. The first portion is disposed on the body, and the second portion is disposed on the first tab. The first non-straight edge is the edge of the second portion that faces away from the first portion.

[0044] In the above scheme, the edge of the first film layer near the first tab is locally concave, which can effectively absorb the expansion of the active material layer toward the first tab, reduce the risk of cracking at the electrical connection between the first tab and the current collector due to the impact of the expansion of the active material layer, and make the battery cell have high reliability.

[0045] According to some embodiments of this application, the battery cell is cylindrical and includes a current collector and an electrode assembly. The electrode assembly is a wound structure and includes a first electrode sheet. The current collector includes a coating area and an empty foil area arranged along a first direction. A film layer is disposed in the coating area. Along the first direction, the first non-straight edge is the edge of the first film layer near the empty foil area.

[0046] In the above scheme, the edge of the first film layer near the empty foil area is locally concave, which can effectively absorb the expansion of the film layer toward the empty foil area, reduce the risk of cracking at the electrical connection between the empty foil area and the current collector due to the impact of the expansion of the active material layer, and make the battery cell have high reliability.

[0047] Secondly, some embodiments of this application provide a battery device including the battery cell provided in the first aspect.

[0048] Thirdly, some embodiments of this application provide an electrical device, including a single battery cell provided in the first aspect, or a battery device provided in the second aspect.

[0049] Fourthly, some embodiments of this application provide a method for manufacturing a single battery cell, including: Provide current collectors; The first active slurry is coated on at least one side of the current collector along its thickness direction, and the edge of the first active slurry in the first direction has a first non-straight edge, the first non-straight edge including a first protrusion and a first concave arranged alternately along the second direction, the first direction, the second direction and the thickness direction being perpendicular to each other. At least a portion of the second active slurry is coated onto the side of the first active slurry away from the current collector.

[0050] In the above scheme, by making the edge of the first active slurry locally concave in the first direction and forming a first non-straight edge, it can effectively provide a space for the first and second active slurries to migrate in the first direction under external force (such as roller pressure), improve the edge thickness uniformity of the negative electrode sheet in the first direction, reduce the problem of poor welding caused by inconsistent root thickness during electrode tab welding, and enable the battery cell to have a high yield and reliability.

[0051] According to some embodiments of this application, coating at least a portion of the second active slurry onto the side of the first active slurry away from the current collector includes: The second active slurry has a second non-straight edge in the first direction, and the second non-straight edge and the first non-straight edge are disposed on the same side. The second non-straight edge includes a second protrusion and a second concave portion arranged alternately along the second direction.

[0052] In the above scheme, by making the edge of the first active slurry locally concave in the first direction to form a first non-straight edge, and making the edge of the second active slurry locally concave in the first direction to form a second non-straight edge, it can effectively provide a space for the first and second active slurries to migrate in the first direction under external force (such as roller pressure), improve the edge thickness uniformity of the electrode in the first direction, reduce the problem of poor welding caused by inconsistent root thickness during electrode tab welding, and enable the battery cell to have a high yield and reliability.

[0053] Fifthly, some embodiments of this application provide a method for manufacturing a single battery cell, including: Provide current collectors; A third active slurry and a first insulating slurry are coated onto the current collector, such that the first insulating slurry has a first non-straight edge away from the third active slurry. The first non-straight edge includes a first protrusion and a first concave portion arranged alternately along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other. At least a portion of the fourth active slurry is coated onto the side of the third active slurry opposite to the current collector.

[0054] According to some embodiments of this application, coating at least a portion of the fourth active slurry onto the side of the third active slurry opposite to the current collector includes: A fourth active slurry and a second insulating slurry are coated on the third active slurry and the first insulating slurry, the third active slurry being located between the fourth active slurry and the current collector, and at least a portion of the first insulating slurry being located between the second insulating slurry and the current collector, such that the second insulating slurry has a second non-straight edge away from the fourth active slurry, the second non-straight edge including a second convex portion and a second concave portion alternately arranged along the second direction.

[0055] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0056] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a schematic diagram of a vehicle in some embodiments of this application; Figure 2 This is an exploded perspective view of a battery device provided in some embodiments of this application; Figure 3 An exploded perspective view of a battery cell provided in some embodiments of this application; Figure 4 This is a schematic diagram of the structure of the first electrode provided in some embodiments of this application; Figure 5 This is a schematic diagram of the internal structure of the first electrode sheet provided in some embodiments of this application; Figure 6 This is a schematic diagram of the current collector and the first membrane layer provided in some embodiments of this application; Figure 7 for Figure 4 Enlarged view of point A in the middle; Figure 8 This is a partial enlarged view of the first electrode in some other embodiments of this application; Figure 9 This is a partial enlarged view of the first electrode in some other embodiments of this application; Figure 10 This is a schematic diagram of the structure of the first electrode provided in other embodiments of this application; Figure 11 Schematic diagram of the internal structure of the first electrode provided in other embodiments of this application; Figure 12 The following is an exploded perspective view of a battery cell in some embodiments of this application, wherein the battery cell is a right parallelepiped; Figure 13 This is a schematic diagram of the structure of the first electrode sheet before slitting, provided in some embodiments of this application; Figure 14 A schematic diagram of the structure of the first electrode of a cylindrical battery cell provided in some embodiments of this application; Figure 15 A flowchart illustrating a method for manufacturing a single battery cell according to some embodiments of this application; Figure 16 A flowchart illustrating a method for manufacturing a battery cell according to other embodiments of this application.

[0058] Icons: 1000 - Vehicle; 100 - Battery Unit; 200 - Controller; 300 - Motor; 20 - Housing; 21 - First Housing Body; 22 - Second Housing Body; 10 - Battery Cell; 11 - Electrode Assembly; 12 - Housing; 120 - Shell; 121 - End Cap; 13 - Current Collector; 14 - Electrode Terminal; 15 - First Electrode; 16 - Current Collector; 160 - Main Body; 161 - First Tab; 162 - Coating Area; 163 - Empty Foil Area; 17 - Film Layer; 18 - First Film Layer; 18a - Third active material layer; 18b - First insulating layer; 180 - First non-straight edge; 1810 - First convex portion; 1811 - First concave portion; 19 - Second film layer; 19a - Fourth active material layer; 19b - Second insulating layer; 190 - Second non-straight edge; 1910 - Second convex portion; 1911 - Second concave portion; z - Thickness direction; x - First direction; y - Second direction; 2000 - First method for manufacturing a battery cell; 3000 - Second method for manufacturing a battery cell. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0061] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0062] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0063] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0064] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0065] In this application, "multiple" means two or more (including two).

[0066] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0067] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0068] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, serves to prevent short circuits to some extent while allowing active ions to pass through.

[0069] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0070] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0071] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0072] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM1), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM6), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0073] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0074] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0075] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0076] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0077] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0078] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0079] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0080] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0081] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0082] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0083] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0084] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0085] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0086] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0087] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0088] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0089] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0090] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0091] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0092] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0093] In some implementations, the electrode assembly has a stacked structure.

[0094] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0095] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0096] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0097] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0098] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0099] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0100] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0101] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0102] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0103] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0104] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0105] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0106] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0107] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0108] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0109] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0110] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0111] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. The energy storage device includes energy storage containers, energy storage cabinets, etc. In some embodiments, one or more energy storage devices may constitute at least part of an energy storage system.

[0112] Battery devices possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of today's new energy development. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters like energy density, cycle life, and discharge capacity. Furthermore, the charge and discharge performance of the battery device must also be taken into account.

[0113] A battery cell includes an electrode, which includes a current collector and a film layer. The film layer may include an active material layer and is coated on at least one side of the current collector in the thickness direction. Generally, after the film layer is coated on the current collector, the electrode is rolled. However, due to changes in processing stress and adhesion, the film layer often migrates towards the edge. Because of varying degrees of migration, a significant thickness abruptness zone forms at the edge of the film layer, causing inconsistent electrode edge thickness. This affects subsequent processes (such as tab shaping and tab welding), impacting yield. Simultaneously, as the number of charge-discharge cycles of the battery cell increases, the active material in the film layer expands and migrates towards the edge, impacting the connection between the tab and the current collector. This can cause cracking at the connection, leading to battery cell failure and affecting the yield and reliability of the battery assembly. To improve the performance of a single battery cell, related technologies may use two film layers arranged along the thickness direction of the current collector. Since the current collector is coated with two film layers, the risk of abrupt thickness changes is higher, and the connection between the tab and the current collector is more likely to crack due to film expansion.

[0114] In view of this, to improve the problem of battery device yield and reliability affected by film migration along the electrode edge, some embodiments of this application provide a battery cell. The battery cell includes a first electrode, which includes a current collector and a film. The film is disposed on at least one side of the current collector in the thickness direction. The film includes a first film and a second film. Along the thickness direction of the current collector, at least a portion of the first film is located between the second film and the current collector. The first film has a first non-straight edge in a first direction. The first non-straight edge includes alternating first protrusions and first concave portions along a second direction. The first direction, the second direction, and the thickness direction are perpendicular to each other.

[0115] In the battery cell provided above, the first film layer has a first non-straight edge in the first direction, and the first non-straight edge is partially concave, so that the first film layer has first protrusions and first concave portions arranged alternately along the second direction. On the one hand, during the manufacturing process of the battery cell, the concave area of ​​the first film layer can provide a space for the active material in the film layer to migrate in the first direction due to external force (such as roller pressure), improve the edge thickness uniformity of the film layer in the first direction, reduce the problem of poor welding due to inconsistent root thickness during tab welding, and make the battery cell have a higher yield and reliability. On the other hand, after the battery cell has undergone a certain number of charge and discharge cycles, the concave area of ​​the first film layer can provide a space for the active material in the film layer to migrate in the first direction due to expansion, reduce the amount of expansion of the film layer in the first direction, thereby reducing the risk of cracking at the welding point between the tab and the current collector due to excessive expansion of the active material, making the battery cell have higher reliability, and thus making the battery device have higher reliability.

[0116] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft.

[0117] The technical solutions described in the embodiments of this application are applicable to battery devices, energy storage devices using battery devices, and electrical devices using battery devices.

[0118] Energy storage devices may include energy storage containers, energy storage cabinets, etc. For example, an energy storage cabinet may include a cabinet and one or more battery cells and / or battery devices mounted on the cabinet.

[0119] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be new energy vehicles, including pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The electrical devices in the embodiments of this application include, but are not limited to, those mentioned above.

[0120] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0121] Figure 1 A schematic diagram of a vehicle provided for some embodiments of this application.

[0122] The electrical device is a vehicle 1000. Inside the vehicle 1000, a controller 200, a motor 300, and a battery device 100 can be installed. The controller 200 controls the battery device 100 to supply power to the motor 300. For example, the battery device 100 can be installed at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, it can serve as the operating power source for the vehicle 1000's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000 but also as the driving power source, replacing or partially replacing fuel or natural gas to provide driving power to the vehicle 1000.

[0123] Please refer to Figure 2 , Figure 2This is an exploded perspective view of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 20 and a battery cell 10, with the battery cell 10 housed within the housing 20.

[0124] The housing 20 provides assembly space for the battery cell 10 and can adopt various structures. In some embodiments, the housing 20 may include a first housing body 21 and a second housing body 22, which overlap each other and together define an assembly space for accommodating the battery cell 10. The second housing body 22 may be a hollow structure open at one end, and the first housing body 21 may be a plate-like structure, with the first housing body 21 covering the open side of the second housing body 22 so that the first housing body 21 and the second housing body 22 together define the assembly space; alternatively, the first housing body 21 and the second housing body 22 may both be hollow structures open on one side, with the open side of the first housing body 21 covering the open side of the second housing body 22.

[0125] Of course, the box formed by the first box body 21 and the second box body 22 can be of various shapes, such as cylinder, cuboid or cube.

[0126] In the battery device 100, there can be one or more battery cells 10 disposed within the housing 20. When there are multiple battery cells 10 disposed within the housing 20, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 10 are connected in both series and parallel configurations. Multiple battery cells 10 can be directly connected in series, in parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 10 is housed within the housing 20. Alternatively, the battery device 100 can also consist of multiple battery cells 10 first connected in series, in parallel, or in a mixed configuration to form battery modules, and then multiple battery modules connected in series, in parallel, or in a mixed configuration to form a whole, which is then housed within the housing.

[0127] In some embodiments, the battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar for connecting multiple battery cells 10 to achieve electrical connection between the multiple battery cells 10.

[0128] For example, the housing 20 is provided with a plurality of battery cell assemblies, each battery cell assembly including a plurality of battery cells 10, and the plurality of battery cells 10 are connected in series with each other through a busbar. In some embodiments, the plurality of battery cell assemblies can be connected in series with each other through a busbar.

[0129] Each battery cell 10 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.

[0130] Some embodiments of this application provide a single battery cell 10; please refer to [link to relevant documentation]. Figures 3-7 , Figure 3 This is an exploded perspective view of the battery cell 10 provided in some embodiments of this application. Figure 4 This is a schematic diagram of the structure of the first electrode 15 provided in some embodiments of this application. Figure 5 This is a schematic diagram of the internal structure of the first electrode 15 provided in some embodiments of this application. Figure 6 This is a schematic diagram of the structure of the current collector 16 and the first active material layer provided in some embodiments of this application. Figure 7 for Figure 4 Enlarged view of point A in the middle.

[0131] The battery cell 10 includes a first electrode 15, which includes a current collector 16 and a film layer 17. The film layer 17 is disposed on at least one side of the current collector 16 in the thickness direction z. The film layer 17 includes a first film layer 18 and a second film layer 19. Along the thickness direction z of the current collector 16, at least a portion of the first film layer 18 is located between the second film layer 19 and the current collector 16. The first film layer 18 has a first non-straight edge 180 in a first direction x. The first non-straight edge 180 includes first protrusions and first recesses arranged alternately along a second direction. The first direction x, the second direction y, and the thickness direction z are all perpendicular to each other.

[0132] The battery cell 10 includes a housing 12. The housing 12 is a component for housing the electrode assembly 11 and the electrolyte (such as electrolyte solution). In some embodiments, the housing 12 is cylindrical, square, or other prismatic in shape.

[0133] In some embodiments, the housing 12 can be a sealed structure or a non-sealed structure. As an example, when the housing 12 is a sealed structure, it can protect the electrode assembly 11 and prevent, to some extent, electrolyte leakage. When the housing 12 is a non-sealed structure, it can still protect the electrode assembly 11, and a sealing bag may be included between the housing 12 and the electrode assembly 11. The sealing bag is used to encapsulate the electrode assembly 11 and the electrolyte, etc. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0134] Optionally, please see Figure 3 The housing 12 may include a housing 120 and an end cap 121. The electrode assembly 11 is disposed inside the housing 120. The end cap 121 is connected to the housing 120 to close the opening of the housing 120, so that the electrode assembly 11 is located in a closed space.

[0135] The electrode assembly 11 includes a positive electrode, a negative electrode, and a separator. The separator is disposed between the positive and negative electrode. Optionally, the electrode assembly 11 can be a stacked structure. Optionally, the electrode assembly 11 can be a wound structure. The first electrode 15 can be either a positive electrode or a negative electrode. Alternatively, both the positive and negative electrode can adopt the structure of the first electrode 15.

[0136] The first electrode 15 includes a current collector 16 and a film layer 17. The current collector 16 can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. The composite current collector can include a polymer material base layer and a metal layer. The film layer 17 can refer to a structural layer containing active material. When the first electrode 15 is a negative electrode, the active material in the film layer 17 includes at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. When the first electrode 15 is a positive electrode, the active material in the film layer 17 includes at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds.

[0137] In some embodiments, when the first electrode 15 is a positive electrode, the film layer 17 may include an active material layer and an insulating layer. The insulating layer may refer to a structural layer containing insulating material. The insulating material in the insulating layer includes, but is not limited to, insulating materials such as ceramics (Al2O3, SiO2), PVDF, and PI.

[0138] Optionally, the membrane layer 17 is disposed on one surface of the current collector 16 in the thickness direction z. Optionally, the membrane layer 17 is disposed on two opposite surfaces of the current collector 16 in the thickness direction z.

[0139] The membrane layer 17 includes a first membrane layer 18 and a second membrane layer 19. Along the thickness direction z of the current collector 16, at least a portion of the first membrane layer 18 is located between the second membrane layer 19 and the current collector 16.

[0140] Optionally, the entire first membrane layer 18 is located between the second membrane layer 19 and the current collector 16.

[0141] Optionally, a portion of the first membrane layer 18 is located between the second membrane layer 19 and the current collector 16, and another portion of the first membrane layer 18 extends beyond the second membrane layer 19, that is, the side of this other portion away from the current collector 16 is not provided with the second membrane layer 19.

[0142] For example, in the manufacturing process of the first electrode 15, a first film layer 18 is first coated on the surface of the current collector 16, and then a second film layer 19 is coated. Subsequently, the surface of the first electrode 15 is subjected to processes such as rolling and drying.

[0143] The active material of the first film layer 18 and the active material of the second film layer 19 may be the same or different. For example, both the active material of the first film layer 18 and the active material of the second film layer 19 may include graphite. Alternatively, the active material of the first film layer 18 may include graphite, and the active material of the second film layer 19 may include a silicon-carbon composite material.

[0144] In some embodiments, the current collector 16 includes a coated area and an uncoated area, with a film layer 17 disposed in the coated area and the uncoated area not coated with the film layer 17. The uncoated area can serve as an electrical output structure for electrical connection to the electrode terminals 14 of the battery cell 10 to realize the input or output of electrical energy. Optionally, the uncoated area can be directly connected to the electrode terminals 14, or the uncoated area can be electrically connected to the electrode terminals 14 through the current collector 13.

[0145] The first direction x is perpendicular to the thickness direction z of the current collector 16. In some embodiments, the first direction x can be the direction from the coated area to the uncoated area.

[0146] Please see Figures 4-7 The first film layer 18 has a first non-straight edge 180 in the first direction x. The first non-straight edge 180 can be understood as the edge of the first active material layer in the first direction x being locally concave to form first convex portions 1810 and first concave portions 1811 alternately arranged along the second direction.

[0147] The term "local concavity" can refer to the fact that at least one position on the edge of the first active material layer in the first direction x is recessed from the uncoated area to the coated area to form a first concave portion 1811, and the first concave portion 1811 forms a first convex portion 1810 on the side along the second direction y.

[0148] In the battery cell 10 provided above, the first film layer 18 has a first non-straight edge 180 in the first direction x, and the first non-straight edge 180 is partially concave, so that the first film layer 18 has a first protrusion 1810 and a first concave portion 1811 alternately arranged in the second direction. On the one hand, during the manufacturing process of the battery cell 10, the concave area of ​​the first film layer 18 can provide a space for the active material of the film layer 17 to migrate in the first direction x due to external force (such as roller pressure), thereby improving the edge thickness uniformity of the film layer 17 in the first direction x and reducing the problem of poor welding caused by inconsistent thickness at the root during electrode welding, thus enabling the battery cell 10 to have a high yield and reliability. On the other hand, after the battery cell 10 has undergone a certain number of charge and discharge cycles, the concave area of ​​the first film layer 18 can provide a space for the active material of the film layer 17 to migrate in the first direction x due to expansion, thereby reducing the amount of expansion of the active material layer along the first direction x, thereby reducing the risk of cracking at the welding point between the electrode and the current collector 13 due to excessive expansion of the active material, thus enabling the battery cell 10 to have high reliability, and consequently enabling the battery device 100 to have high reliability.

[0149] According to some embodiments of this application, the outline of the first protrusion 1810 is triangular, arc-shaped, or trapezoidal.

[0150] The outline of the first protrusion 1810 can be triangular, arc-shaped, or trapezoidal. This can be understood as follows: when viewing the first electrode 15 along the thickness direction z of the current collector 16, the outline shape of the first protrusion 1810 can be triangular, arc-shaped, or trapezoidal.

[0151] Please see Figure 7 The triangular outline of the first protrusion 1810 can be understood as having two outline lines, both of which are straight or approximately straight. The ends of the two outline lines facing the uncoated area are connected to form one corner of the triangle. Along the second direction y, when two adjacent first protrusions 1810 are connected, the outline of the first recess 1811 between the two adjacent first protrusions 1810 can also be triangular, meaning the ends of the two adjacent outline lines of the two adjacent first protrusions 1810 are connected to form the first recess 1811. Along the second direction y, when two adjacent first protrusions 1810 are spaced apart, the ends of the two adjacent outline lines of the two adjacent first protrusions 1810 are spaced apart, and the ends of the two outline lines are connected by a straight transition edge or an arc-shaped transition edge, so that the two outline lines and the transition edge together form a trapezoidal or similar trapezoidal first recess 1811.

[0152] Please see Figure 8 , Figure 8The enlarged view of the first electrode in some embodiments of this application shows that the outline of the first protrusion 1810 is arc-shaped, which can be understood as the outline of the first protrusion 1810 being an arc line. Optionally, along the second direction y, the outlines of two adjacent first protrusions 1810 are directly connected and form a sharp point, so that the outline of the first concave portion 1811 between the two first protrusions 1810 is a conical shape with a pointed inner edge and a larger outer edge. Optionally, along the second direction y, the outlines of two adjacent first protrusions 1810 are connected by a transition edge, so that the outline of the first concave portion 1811 between the two first protrusions 1810 is a frustum-shaped cone.

[0153] Please see Figure 9 , Figure 9 The enlarged view of the first electrode sheet in some embodiments of this application shows that the trapezoidal outline of the first protrusion 1810 can be understood as having three outline lines, all of which are straight or approximately straight. These three outline lines include a first outline line, a second outline line, and a third outline line. Along the second direction y, the first and second outline lines are positioned opposite each other. The ends of the first and second outline lines facing the uncoated area are connected by the third outline line. The first and second outline lines can be the two sides of a trapezoid, and the third outline line can be the upper base of the trapezoid. Along the second direction y, when two adjacent first protrusions 1810 are connected, the outline of the first recess 1811 between two adjacent first protrusions 1810 can be triangular. Along the second direction y, when two adjacent first protrusions 1810 are spaced apart, the outline of the first recess 1811 between two adjacent first protrusions 1810 can be trapezoidal.

[0154] In the above solution, by setting the outline of the first protrusion 1810 to a triangle, arc, or trapezoid, the area where the first concave portion 1811 is located effectively provides a space for the active material of the film layer 17 to migrate due to external force or expansion force, thereby improving the problem of inconsistent edge thickness of the film layer 17 or excessive expansion of the film layer 17 along the first direction x, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0155] Optionally, when the first protrusion 1810 is triangular, its sharp corner features have good stress release and dispersion characteristics; when the first protrusion 1810 is arc-shaped, its smooth transition contour can effectively avoid stress concentration and prevent the coating from peeling off during processing to the greatest extent; when the first protrusion 1810 is trapezoidal, it achieves an excellent balance between mechanical stability, mold life and process simplicity.

[0156] Optionally, the first non-straight edge 180 can be achieved through high-precision die cutting, laser cutting, or digital spraying mask techniques.

[0157] According to some embodiments of this application, the first non-straight edge 180 includes a plurality of first protrusions 1810 and a plurality of first recesses 1811.

[0158] In some embodiments, the first non-straight edge 180 of the first film layer 18 is recessed at multiple locations to form a plurality of first protrusions 1810 and a plurality of first recesses 1811.

[0159] In the above scheme, the first non-straight edge 180 of the first film layer 18 forms a plurality of first protrusions 1810 and a plurality of first recesses 1811 arranged alternately along the second direction y, which can provide multiple accommodating spaces for the active material, effectively improving the problem of inconsistent edge thickness of the film layer 17 or excessive expansion of the film layer 17 along the first direction x, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0160] According to some embodiments of this application, a plurality of first protrusions 1810 are arranged continuously or spaced apart along the second direction y.

[0161] The continuous arrangement of multiple first protrusions 1810 can be understood as the outlines of two adjacent first protrusions 1810 being directly connected.

[0162] The multiple first protrusions 1810 are spaced apart, which can be understood as the outlines of two adjacent first protrusions 1810 being connected by a transition edge.

[0163] For example, with Figure 7 For example, the outline of the first protrusion 1810 is triangular, and two adjacent first protrusions 1810 are spaced apart. The outlines of two adjacent first protrusions 1810 are connected by a straight transition edge, so that the outline of the first concave part 1811 is trapezoidal.

[0164] For example, with Figure 8 For example, the outline of the first protrusion 1810 is arc-shaped, and two adjacent first protrusions 1810 are continuously arranged. The outlines of two adjacent first protrusions 1810 are connected, so that the outline of the first concave part 1811 is a conical shape with a pointed inner part and a larger outer part.

[0165] In the above solution, by setting the multiple first protrusions 1810 continuously, the coating cycle of the first film layer 18 can be effectively improved, which is beneficial to improving the manufacturing efficiency of the battery cell 10. By setting the multiple first protrusions 1810 spaced apart, the risk of stress concentration caused by sharp corners between the first protrusions 1810 and the first recesses 1811, which leads to cracking of the film layer 17, can be reduced, which is beneficial to improving the reliability of the battery cell 10.

[0166] According to some embodiments of this application, the second film layer 19 has a second non-straight edge 190 in the first direction x, the second non-straight edge 190 and the first non-straight edge 180 are disposed on the same side, and the second non-straight edge 190 includes a second protrusion 1910 and a second concave portion 1911 alternately arranged along the second direction y.

[0167] Please see Figure 4 , Figure 5 and Figure 7 The second film layer 19 has a second non-straight edge 190 in the first direction x.

[0168] The second non-straight edge 190 can be understood as the edge of the second film layer 19 being locally concave in the first direction x to form a second convex portion 1910 and a second concave portion 1911 alternating along the second direction y.

[0169] The local concavity can be understood as at least one location of the second non-straight edge 190 being concave in the direction from the uncoated area to the coated area, so that the edge of the second film layer 19 forms a continuous concave-convex second non-straight edge 190 similar to a tooth arrangement.

[0170] In the above scheme, the second film layer 19 has a second non-straight edge 190 in the first direction x. The second non-straight edge 190 is partially concave, so that the edge of the second film layer 19 forms a second convex part and a second concave part arranged alternately along the second direction. This can effectively accommodate the active material that migrates to the first direction x due to external force or internal expansion force, improve the problem of inconsistent edge thickness of film layer 17 or excessive expansion of film layer 17 along the first direction x, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0171] According to some embodiments of this application, along the second direction, the distance between two adjacent first protrusions 1810 and the distance between two adjacent second protrusions 1910 are different.

[0172] Along the second direction, the distance between two adjacent first protrusions 1810 can refer to the maximum distance between two adjacent first protrusions 1810. Along the second direction, the distance between two adjacent second protrusions 1910 can refer to the maximum distance between two adjacent second protrusions 1910.

[0173] For example, please see Figure 7 Taking the outline of the first protrusion 1810 as a triangle as an example, the distance between two first protrusions 1810 can refer to the distance between the apex of two adjacent first protrusions 1810. Figure 7 The symbol P in the middle indicates the distance between the two first protrusions 1810.

[0174] In the above scheme, by setting the spacing of the first protrusion 1810 to be different from the spacing of the second protrusion 1910, the first protrusion 1810 and the second concave portion 1911 can at least partially overlap. The second protrusion 1910 and the first concave portion 1811 can at least partially overlap. On the one hand, this can increase the connection area between the first non-straight edge 180 and the second non-straight edge 190, which is beneficial to improving the structural stability of the film layer 17. On the other hand, it can cause the active material to migrate to the thinner part of the stack between the first film layer and the second film layer when subjected to external force or expansion force. This results in high thickness consistency at the edge of the film layer 17 and low expansion of the film layer 17 in the first direction x. This makes the battery cell 10 have a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0175] Optionally, the distance between two adjacent first protrusions 1810 can be greater than the distance between two adjacent second protrusions 1910. Optionally, the first protrusion 1810 has a larger dimension along the second direction y, and the second protrusion 1910 has a smaller dimension along the second direction y. In the first electrode 15, the lower first film layer has large serrations, and the upper second film layer has small serrations. This structure utilizes the tooth distribution characteristics of the upper and lower film layers to achieve efficient stress dispersion in the transverse and longitudinal directions and form a smooth thickness transition zone. This design can significantly improve the mechanical matching characteristics at the interface during subsequent processing such as electrode tab folding and welding, providing better buffering and adaptability, and fundamentally improving the integrity and reliability of the electrode tab connection.

[0176] According to some embodiments of this application, the first protrusion 1810 and the second protrusion 1910 are misaligned along the second direction y.

[0177] The misalignment of the first protrusion 1810 and the second protrusion 1910 can be understood as the first concave portion 1811 and the second protrusion 1910 being at least partially overlapping.

[0178] For example, the second protrusion 1910 may be located in the area where the first recess 1811 is located.

[0179] In the above scheme, by staggering the first protrusion 1810 and the second protrusion 1910 along the second direction y, on the one hand, the connection area between the first non-straight edge 180 and the second non-straight edge 190 can be increased, which is beneficial to improving the structural stability of the film layer 17. On the other hand, when the active material is subjected to external force or expansion force, it migrates to the part with thinner stacking thickness between the first film layer and the second film layer, thereby making the thickness uniformity of the edge part of the film layer 17 high and the expansion degree of the film layer 17 towards the first direction x low, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0180] According to some embodiments of this application, along the first direction x, the maximum dimension L of the first protrusion 1810 satisfies: 0.5mm≤L≤3mm.

[0181] The maximum dimension of the first protrusion 1810 along the first direction x can be understood as the maximum depth of the inward recess of the first non-straight edge 180. See also... Figure 6 Along the first direction x, the maximum dimension L of the first protrusion 1810 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm...2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm or any value between two adjacent values.

[0182] Optionally, along the first direction x, the maximum dimension L of the first protrusion 1810 satisfies: 0.5mm≤L≤2mm.

[0183] Optionally, along the first direction x, the maximum dimension L of the first protrusion 1810 satisfies: 0.5mm≤L≤1.5mm.

[0184] Optionally, the electrode assembly is unfolded, the first electrode 15 is laid flat, and the maximum dimension L of the first protrusion 1810 is measured by a laser rangefinder.

[0185] In the above scheme, the maximum size of the first protrusion 1810 along the first direction x is greater than or equal to 0.5 mm, which can provide a larger accommodation space for the migration of the active material layer along the first direction x, improve the problem of inconsistent edge thickness of the film layer 17 or excessive expansion of the film layer 17 along the first direction x, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability; the maximum size of the first protrusion 1810 along the first direction x is less than or equal to 3 mm, which can reduce the risk of a decrease in the amount of active material caused by the excessive size of the first protrusion, resulting in a decrease in the energy density of the battery cell 10, so that the battery cell 10 has a high energy density.

[0186] According to some embodiments of this application, at least a portion of the first film layer 18 extends beyond the second film layer 19 along a first direction x.

[0187] In some embodiments, the first film layer 18 may extend beyond the second film layer 19, that is, the dimension of the first film layer 18 along the first direction x is greater than the dimension of the second film layer 19 along the first direction x. For example, the first non-straight edge 180 of the first film layer 18 may extend beyond the second film layer 19 along the first direction x.

[0188] In some embodiments, a portion of the first film layer 18 may extend beyond the second film layer 19. For example, a portion of the first non-straight edge 180 may be located between the second film layer 19 and the uncoated area.

[0189] Optionally, the first protrusion 1810 may extend beyond the second film layer 19 along the first direction x, and a portion of the second film layer 19 may be located in the region where the first recess 1811 is located.

[0190] In the above scheme, by setting at least a portion of the first film layer 18 to extend beyond the second film layer 19, the first film layer 18 can effectively support the second film layer 19, and the film layer 17 forms a transition region with gradually decreasing thickness along the edge of the first direction x. When the film layer 17 is subjected to external force or internal expansion force and migrates in the first direction x, it can fill the thickness of the transition region, so that the thickness uniformity of the entire first electrode 15 is high, which is beneficial to improving the yield and reliability of the battery cell 10, and thus beneficial to improving the yield and reliability of the battery device 100.

[0191] Alternatively, in other embodiments, the first film layer 18 and the second film layer 19 are stacked along the thickness direction z and have the same size.

[0192] Alternatively, in other embodiments, a portion of the second film layer 19 extends beyond the first film layer 18 along the first direction x.

[0193] According to some embodiments of this application, along the first direction x, the second film layer 19 extends beyond the first recess 1811.

[0194] In some embodiments, the first non-straight edge 180 of the first film layer 18 is recessed to the inside of the second non-straight edge 190 of the second film layer 19, so that a portion of the second film layer 19 can be located in the region where the first recess 1811 is located.

[0195] In some embodiments, at least a portion of the second protrusion 1910 of the second film layer 19 may be located in the region where the first recess 1811 is located.

[0196] In the above scheme, a portion of the second film layer 19 can be located in the concave region of the first film layer 18, which allows for a smooth transition in thickness at the edge of the film layer 17. When the second film layer 19 is subjected to external force or internal expansion force, it can effectively guide the active material of the second film layer 19 to fill the concave region of the first film layer 18, thereby improving the problem of inconsistent thickness at the edge of the film layer 17 or excessive expansion of the film layer 17 along the first direction x, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0197] According to some embodiments of this application, a portion of the first protrusion 1810 is located between the second film layer 19 and the current collector 16, and another portion of the first protrusion 1810 extends beyond the second film layer 19 along a first direction x.

[0198] In some embodiments, a portion of the second film layer 19 may be located on the first protrusion 1810, such that a portion of the first protrusion 1810 is held by the second film layer 19 and the current collector 16.

[0199] In some embodiments, see Figure 7 A portion of the first protrusion 1810 is located between the second film layer 19 and the current collector 16, and another portion of the first protrusion 1810 is located on the current collector 16 and extends beyond the second film layer 19 along the first direction x.

[0200] In the above scheme, a portion of the first protrusion 1810 is sandwiched between the second film layer 19 and the current collector 16, which can improve the structural stability of the edge portion of the first active material layer and reduce the risk of the first protrusion 1810 falling off from the current collector 16. Another portion of the first protrusion 1810 extends beyond the second film layer 19, which can effectively accommodate the active material of the second film layer 19 that migrates in the first direction x due to external force or internal expansion force in the concave area of ​​the first active material layer, so that the battery cell 10 has a high yield and reliability, and thus the battery device 100 has a high yield and reliability.

[0201] According to some embodiments of this application, the first electrode 15 is a negative electrode, the first film layer 18 is a first active material layer, and the second film layer 19 is a second active material layer. The first active material layer can be a structural layer containing a negative electrode active material, and the second active material layer can be a structural layer containing a negative electrode active material.

[0202] According to some embodiments of this application, the coefficient of expansion of the first active material layer is smaller than that of the second active material layer.

[0203] The coefficient of thermal expansion refers to the degree of volume change of active materials during battery charging and discharging due to lithium ion insertion / extraction, reflecting the volume deformation capability of active materials in electrochemical reactions. For example, graphite expands by about 10-12% when fully lithium-intercalated; silicon-based materials can expand by more than 300%.

[0204] Alternatively, the method for measuring the expansion coefficient may include in-situ XRD (real-time monitoring of lattice parameter changes), SEM / TEM (observation of particle morphology evolution), or electrochemical dilatometer measurement.

[0205] In the above scheme, the first active material layer has a small coefficient of expansion, which can provide stable support for the upper second active material layer and effectively absorb and buffer the expansion stress from the second active material layer, preventing the current collector 16 from wrinkling or being damaged. Furthermore, by using a first non-straight edge 180 at the edge of the first active material layer, it can effectively accommodate active material that migrates from the second active material layer due to external forces or expansion forces, resulting in higher yield and reliability for the battery cell 10, and consequently, higher yield and reliability for the battery device 100.

[0206] According to some embodiments of this application, the material of the first active material layer includes graphite, and the material of the second active material layer includes a silicon-carbon composite material.

[0207] Graphite can be artificial graphite. Silicon-carbon composites include silicon (Si) particles, and the composite methods of silicon-carbon composites include, but are not limited to, coating type (carbon-coated silicon core-shell structure), embedding type (silicon embedded in carbon matrix), and hybrid type.

[0208] In the above scheme, the first active material layer includes graphite. Utilizing the characteristics of graphite's small expansion and excellent adhesion to the current collector 16, it provides a robust support platform for the second active material layer, effectively absorbing and buffering the expansion stress from the second active material layer and preventing wrinkles or damage to the current collector 16. The second active material layer includes a high-specific-capacity silicon-carbon composite material, which can effectively improve the energy density of the battery cell 10. To this end, the support of the lower graphite layer restricts most of the expansion of the silicon-carbon composite material to the vertical direction, rather than the horizontal direction, thereby significantly reducing the overall lateral stress of the film layer 17, improving structural integrity, and enabling the battery cell 10 to possess a higher energy density.

[0209] According to some embodiments of this application, the mass of the first active material layer is greater than the mass of the second active material layer.

[0210] In the above scheme, by setting the mass of the first active material layer to be greater than that of the second active material layer, on the one hand, the first active material layer can provide stable support for the second active material layer, and on the other hand, it can ensure the low internal resistance of the first electrode 15 to a certain extent, so that the battery cell 10 has a high charge and discharge rate.

[0211] According to some embodiments of this application, the mass ratio of the first active material layer to the second active material layer is greater than 1 and less than 9.

[0212] In some embodiments, the ratio of the mass of the first active material layer to the mass of the second active material layer can be 1, 2, 3...9 or between two adjacent values.

[0213] For example, the mass of the first active material layer accounts for 80% of the total mass of the membrane layer 17, and the mass of the second active material layer accounts for 20% of the total mass of the membrane layer 17.

[0214] According to some embodiments of this application, please see Figure 10 and Figure 11 , Figure 10 This is a schematic diagram of the structure of the first electrode provided in other embodiments of this application. Figure 11 A schematic diagram of the internal structure of the first electrode provided for other embodiments of this application.

[0215] The first electrode 15 is a positive electrode, the first film layer 18 includes a third active material layer 18a and a first insulating layer 18b that are interconnected, the first insulating layer 18b and the third active material layer 18a are arranged along a first direction x, the first insulating layer 18b has a first non-straight edge 180, and the second film layer 19 includes a fourth active material layer 19a.

[0216] The active material in the third active material layer 18a includes at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. The first insulating layer 18b may refer to a structural layer containing insulating material, and the insulating material in the first insulating layer 18b includes, but is not limited to, insulating materials such as ceramics (Al2O3, SiO2), PVDF, and PI.

[0217] The active material in the fourth active material layer 19a includes at least one of the following materials: lithium phosphate, lithium transition metal oxide and their respective modified compounds.

[0218] For example, during the manufacturing process of the positive electrode sheet, a first positive electrode active slurry and a first insulating slurry are coated on the current collector 16 to form a third active material layer 18a and a first insulating layer 18b on the current collector 16, and then a second positive electrode active slurry is coated to form a fourth active material layer 19a.

[0219] Optionally, the first insulating layer 18b is located on the current collector 16 and is connected to the third active material layer 18a. Along the first direction x, the edge of the first insulating layer 18b away from the third active material layer 18a is partially concave to form a first non-straight edge 180. The first non-straight edge 180 includes a first protrusion 1810 and a first concave portion 1811 arranged alternately along the second direction y, so that the edge portion of the first insulating layer 18b forms a tooth-like structure with continuous concavity and convexity along the second direction y.

[0220] Optionally, along the first direction x, the edge of the fourth active material layer 19a is partially concave to form a second non-straight edge 190. The second non-straight edge 190 includes a second convex portion 1910 and a second concave portion 1911 arranged alternately along the second direction y, so that the edge portion of the fourth active material layer 19a forms a tooth-like structure with continuous concavity and convexity along the second direction y.

[0221] In the battery cell provided above, the first electrode 15 is the positive electrode, and the positive electrode improves the overall performance of the battery cell through the synergistic effect of the third active material layer 18a and the fourth active material layer 19a. The side of the first insulating layer 18b away from the third active material layer 18a is locally concave, so that the side of the first insulating layer 18b away from the third active material layer 18a forms a first protrusion 1810 and a first concave portion 1811 alternately arranged along the second direction. On the one hand, during the manufacturing process of the battery cell, the concave area of ​​the first insulating layer 18b can provide a space for the active materials of the third active material layer 18a, the fourth active material layer 19a, and the first insulating layer 18b to migrate in the first direction under external force (such as roller pressure), making the edge thickness of the entire positive electrode sheet uniform in the first direction, reducing the problem of poor welding caused by inconsistent thickness at the root during positive electrode tab welding, and enabling the battery cell to have a high yield and reliability. On the other hand, after the battery cell has undergone a certain number of charge and discharge cycles, the concave area of ​​the first insulating layer 18b can provide a space for the active materials of the third active material layer 18a and the fourth active material layer 19a to migrate in the first direction due to expansion, reducing the amount of expansion of the active materials along the first direction, thereby reducing the risk of cracking at the welding point between the positive electrode tab and the current collector due to excessive expansion of the active materials, making the battery cell have high reliability, and thus enabling the battery device to have high reliability.

[0222] According to some embodiments of this application, the second film layer 19 includes a second insulating layer 19b connected to a fourth active material layer 19a along the thickness direction z. A third active material layer 18a is located between the fourth active material layer 19a and the current collector 16, and at least a portion of the first insulating layer 18b is located between the second insulating layer 19b and the current collector 16.

[0223] The second insulating layer 19b may refer to a structural layer containing insulating material. The insulating material in the second insulating layer 19b includes, but is not limited to, insulating materials such as ceramics (Al2O3, SiO2), PVDF, and PI.

[0224] For example, during the manufacturing process of the positive electrode sheet, a first positive electrode active slurry and a first insulating slurry are coated on the current collector 16 to form a third active material layer 18a and a first insulating layer 18b on the current collector 16, and then a second positive electrode active slurry and a second insulating slurry are coated to form a fourth active material layer 19a and a second insulating layer 19b.

[0225] Optionally, the first insulating layer 18b is located on the current collector 16 and is connected to the third active material layer 18a, and the second insulating layer 19b is located entirely on the side of the first insulating layer 18b away from the current collector 16.

[0226] Optionally, the first insulating layer 18b is located on the current collector 16 and is connected to the third active material layer 18a. A portion of the second insulating layer 19b is located on the side of the first insulating layer 18b away from the current collector 16, and another portion of the second insulating layer 19b extends beyond the first insulating layer 18b along the first direction x and is located on the current collector 16.

[0227] Optionally, along the first direction x, the edge of the second insulating layer 19b away from the fourth active material layer 19a is partially recessed to form a second non-straight edge 190. The second non-straight edge 190 includes a second convex portion 1910 and a second concave portion 1911 arranged alternately along the second direction y, so that the edge portion of the second insulating layer 19b forms a tooth-like structure with continuous concavity and convexity along the second direction y.

[0228] In the above scheme, by providing a second insulating layer 19b on one side of the fourth active material layer 19a along the first direction x, and at least a portion of the first insulating layer 18b being located between the second insulating layer 19b and the current collector 16, the connection stability between the first insulating layer 18b and the current collector 16 can be high. This allows the concave area of ​​the first insulating layer 18b to effectively provide a space for the active materials of the third active material layer 18a and the fourth active material layer 19a to migrate in the first direction x due to external force or expansion, which is beneficial to improving the reliability of the battery cell and thus the reliability of the battery device.

[0229] According to some embodiments of this application, the expansion coefficient of the third active material layer 18a is greater than that of the fourth active material layer 19a.

[0230] The coefficient of thermal expansion refers to the relative change in length or volume caused by a unit change in temperature. The fact that the coefficient of thermal expansion of the third active material layer 18a is greater than that of the fourth active material layer 19a can be understood as follows: after a certain number of charge-discharge cycles of the battery cell 10, the expansion amount of the third active material layer 18a is greater than that of the fourth active material layer 19a.

[0231] In the above scheme, the side of the first insulating layer 18b away from the third active material layer 18a is partially concave, which can effectively accommodate the active material that migrates due to the expansion of the third active material layer 18a and the fourth active material layer 19a, so that the battery cell 10 has a high yield and reliability, and thus the battery device has a high yield and reliability.

[0232] According to some embodiments of this application, the active material of the third active material layer 18a includes a ternary material, and the active material of the fourth active material layer 19a includes lithium iron phosphate.

[0233] In the above scheme, the third active material layer 18a is an energy layer with high active material energy density, and the fourth active material layer 19a is a safety layer with stable active material structure, which can effectively reduce the risk of thermal runaway.

[0234] Optionally, in some embodiments where the active material of the third active material layer 18a includes a ternary material and the active material of the fourth active material layer 19a includes lithium iron phosphate, the size of the teeth of the first tooth structure can be larger than that of the teeth of the second tooth structure.

[0235] According to some embodiments of this application, the mass of the fourth active material layer 19a is greater than the mass of the third active material layer 18a.

[0236] In the above scheme, by setting the mass of the third active material layer 18a to be less than the mass of the fourth active material layer 19a, the fourth active material layer 19a effectively acts as a safety layer, which is beneficial to improving the reliability of the battery cell 10.

[0237] According to some embodiments of this application, the mass ratio of the fourth active material layer 19a to the mass ratio of the third active material layer 18a is greater than 1 and less than 9.

[0238] In some embodiments, the ratio of the mass of the fourth active material layer 19a to the mass of the third active material layer 18a can be 1, 2, 3...9 or between two adjacent values.

[0239] For example, the mass of the fourth active material layer 19a accounts for 70% of the total mass of the active material layer (the sum of the masses of the third active material layer 18a and the fourth active material layer 19a), and the mass of the third active material layer 18a accounts for 30% of the total mass of the active material layer.

[0240] According to some embodiments of this application, please refer to Figure 12 , Figure 12 This is an exploded perspective view of a battery cell 10 in some embodiments of this application, wherein the battery cell 10 is a right parallelepiped. The battery cell 10 includes a current collector 13 and an electrode assembly 11. The electrode assembly 11 includes a first electrode 15. The current collector 16 includes a body 160 and at least one first tab 161. The body 160 has a third edge in a first direction x, and at least one first tab 161 extends from the third edge and is electrically connected to the current collector 13. The first film layer 18 includes a first portion and a second portion. The first portion is disposed on the body 160, and the second portion is disposed on the first tab 161. A first non-straight edge 180 is the edge of the second portion that faces away from the first portion.

[0241] The fact that the battery cell 10 is a right parallelepiped can be understood as the battery cell 10 being square, and the outer casing 12 of the battery cell 10 being square.

[0242] In some embodiments, in the square-shaped battery cell 10, the electrode assembly 11 has a stacked structure. The electrode assembly 11 includes a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators, with the plurality of positive electrode plates and the plurality of negative electrode plates alternately stacked, and the separators located between the positive electrode plates and the negative electrode plates.

[0243] The first electrode 15 can be either a positive or negative electrode. During the manufacturing process of the first electrode 15, after coating, the roll of the first electrode 15 can be die-cut to form multiple first electrode tabs 161, and then slitting can be performed to divide the roll into multiple first electrode sheets 15. See also... Figure 13 , Figure 13 This is a schematic diagram of the structure of the first electrode 15 before slitting, as provided in some embodiments of this application. The roll of the first electrode 15 is slitting. Figure 13 The slitting line is shown by dashed line B. After slitting, the first electrode is obtained. The current collector 16 of the first electrode includes a main body 160 and a first tab 161. The main body 160 is the main part of the current collector 16 and its surface is coated with a film layer 17. The first tab 161 is a structural member extending from the third edge of the main body 160. The first tab 161 is used to electrically connect with the current collector 13 and is electrically connected to the electrode terminal 14 through the current collector 13.

[0244] In some embodiments, at least a portion of the first protrusion 1810 may be located on the first tab 161.

[0245] For example, the entire first protrusion 1810 may be located on the first tab 161.

[0246] In some embodiments, at least a portion of the first recess 1811 may be located on the first tab 161. Exemplarily, a portion of the first recess 1811 may be located on the body 160, and another portion may be located on the first tab 161.

[0247] Optionally, the second protrusion 1910 and / or the second recess 1911 may be located at least partially on the first tab 161.

[0248] In the above scheme, the edge of the first film layer 18 near the first tab 161 is partially concave, which can effectively absorb the expansion of the film layer 17 toward the first tab 161, reduce the risk of cracking of the electrical connection between the first tab 161 and the current collector 13 due to the impact of the expansion of the film layer 17, and make the battery cell 10 have high reliability.

[0249] According to some embodiments of this application, please refer to Figure 3 and Figure 14 , Figure 14 This is a schematic diagram of the structure of the first electrode 15 of a cylindrical battery cell 10 provided in some embodiments of this application. The battery cell 10 is cylindrical and includes a current collector 13 and an electrode assembly 11. The electrode assembly 11 has a wound structure and includes the first electrode 15. The current collector 16 includes a coating area 162 and an empty foil area 163 arranged along the first direction x. A film layer 17 is disposed in the coating area 162. The empty foil area 163 is electrically connected to the current collector 13. Along the first direction x, the first non-straight edge 180 is the edge of the first film layer 18 near the empty foil area 163.

[0250] The fact that the battery cell 10 is cylindrical can be understood as the battery cell 10 being cylindrical and the outer casing 12 of the battery cell 10 being cylindrical.

[0251] In some embodiments, in the cylindrical battery cell 10, the electrode assembly 11 has a wound structure. The electrode assembly 11 includes a positive electrode, a negative electrode, and a separator. The separator is disposed between the positive and negative electrode and is wound about the winding axis to form a wound structure. The first electrode 15 can be either a positive electrode or a negative electrode.

[0252] Optionally, the current collector 16 of the first electrode 15 includes a coated area 162 and an empty foil area 163 arranged along the first direction x. The coated area 162 is the area coated with the film layer 17, and the empty foil area 163 is the area not coated with the film layer 17. The empty foil area 163 serves as the first electrode tab and is electrically connected to the current collector 13. The current collector 13 can be electrically connected to the electrode terminal 14. In some embodiments, after the negative electrode, positive electrode, and separator are wound into a wound structure, the empty foil area 163 located on the first direction x side can be kneaded into a single unit by a flattening process to be electrically connected to the current collector 13.

[0253] Please see Figure 14 The first non-straight edge 180 of the first film layer 18 is the edge of the first film layer 18 near the empty foil area 163. In some embodiments, after the empty foil area 163 is flattened, at least a portion of the first protrusion 1810 and / or the first concave portion 1811 of the first film layer 18 can be bent along with the empty foil area 163. In some embodiments, after the empty foil area 163 is flattened, at least a portion of the second protrusion 1910 and / or the second concave portion 1911 of the second film layer 19 can be bent along with the empty foil area 163.

[0254] In the above scheme, the first film layer 18 is partially concave at the edge near the empty foil area 163, which can effectively absorb the expansion of the film layer 17 toward the empty foil area 163, reduce the risk of cracking at the electrical connection between the empty foil area 163 and the current collector 13 due to the impact of the expansion of the film layer 17, and make the battery cell 10 have high reliability.

[0255] Some embodiments of this application provide a battery device 100, including the battery cell 10 described above. See also... Figure 2 The battery device 100 includes a battery cell 10.

[0256] For example, the battery device 100 includes a housing and battery cells 10, the battery cells 10 being housed within the housing. In the battery device 100, the battery cells 10 disposed within the housing can be one or more. When there are multiple battery cells 10 disposed within the housing, the multiple battery cells 10 can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that the multiple battery cells 10 are connected in both series and parallel configurations.

[0257] Some embodiments of this application also provide an electrical device, which includes the battery cell 10 or battery device 100 described above.

[0258] For example, the electrical device is a vehicle 1000, and the battery cell 10 and / or battery device 100 can serve as the operating power source for the vehicle 1000, for example, for the power requirements of the vehicle 1000 during startup, navigation and operation.

[0259] This application provides a method for manufacturing a first type of battery cell, 2000, in some embodiments. Please refer to [link to relevant documentation]. Figure 15 , Figure 15 A flowchart of a method 2000 for manufacturing a first type of battery cell provided in some embodiments of this application.

[0260] The first method for manufacturing a single battery cell 2000 includes: S1, Provide current collector 16; S2. The first active slurry is coated on at least one side of the current collector 16 along its thickness direction z, and the edge of the first active slurry in the first direction x has a first non-straight edge 180, the first non-straight edge 180 including a first protrusion 1810 and a first concave portion 1811 arranged alternately along the second direction y, the first direction x, the second direction y and the thickness direction z are perpendicular to each other. S3. At least a portion of the second active slurry is coated onto the side of the first active slurry away from the current collector 16.

[0261] In some embodiments, a method for manufacturing a battery cell 10 is provided, which can manufacture the first electrode 15 in the battery cell 10 described above.

[0262] The first active slurry is a fluid-like active material that, after drying, forms a first active material layer. The second active slurry is also a fluid-like active material that, after drying, forms a second active material layer. The first electrode 15 can be a negative electrode. Both the first and second active slurries can contain negative electrode active materials.

[0263] Optionally, in step S2, after coating the current collector 16 with the first active slurry, a first non-straight edge 180 can be formed at the edge of the first film layer 18 by means of high-precision die cutting, laser cutting or digital spraying mask.

[0264] Optionally, in step S2, during the process of coating the first active slurry on the current collector 16, the coating die pad can be optimized and the die pad can be designed to correspond to the shape of the first non-straight edge 180, so that the active slurry is intermittently distributed at the die outlet, so that after the first active slurry dries to form the first film layer 18, the edge of the first film layer 18 forms the first non-straight edge 180.

[0265] Optionally, in step S2, during the process of coating the first active slurry on the current collector 16, the zebra coating method can be used. By adjusting the coating pressure in the mold cavity and the Teflon treatment on both sides of the mold cavity, an uneven coating thickness can be achieved in the edge area of ​​the first active slurry, thereby indirectly forming the first non-straight edge 180.

[0266] Optionally, in step S2, before coating the current collector 16 with the first active slurry, an adhesive tape corresponding to the first non-straight edge 180 is provided on the edge of the current collector 16, and then the first active slurry is coated. After removing the adhesive tape, the first non-straight edge 180 is formed.

[0267] Optionally, during the coating of the first active slurry onto the current collector 16, edge processing can be controlled by reducing or increasing the surface tension of the slurry to control the flowability of the slurry during drying in order to form a first non-straight edge 180.

[0268] In the above scheme, by making the edge of the first active slurry locally concave in the first direction x and forming a first non-straight edge 180, it can effectively provide a space for the first and second active slurries to migrate in the first direction x under external force (such as roller pressure), improve the edge thickness uniformity of the first electrode 15 in the first direction x, reduce the problem of poor welding caused by inconsistent root thickness during electrode tab welding, and enable the battery cell 10 to have a high yield and reliability.

[0269] According to some embodiments of this application, step S3, coating at least a portion of the second active slurry onto the side of the first active slurry away from the current collector 16, includes: The second active slurry has a second non-straight edge 190 in the first direction x, the second non-straight edge 190 and the first non-straight edge 180 are disposed on the same side, and the second non-straight edge 190 includes a second protrusion 1910 and a second concave portion 1911 alternately arranged along the second direction y.

[0270] In the above scheme, by making the edge of the first active slurry locally concave in the first direction x to form a first non-straight edge 180, and making the edge of the second active slurry locally concave in the first direction x to form a second non-straight edge 190, it can effectively provide a space for the first and second active slurries to migrate in the first direction x under external force (e.g., roller pressure), improve the edge thickness uniformity of the first electrode 15 in the first direction x, reduce the problem of poor welding caused by inconsistent root thickness during electrode tab welding, and enable the battery cell 10 to have a high yield and reliability.

[0271] A second method for manufacturing a battery cell is provided according to some embodiments of this application. Please refer to [link to relevant documentation]. Figure 16 , Figure 16 A flowchart illustrating a second battery cell manufacturing method 3000 provided for other embodiments of this application.

[0272] The second method for manufacturing a single battery cell 3000 includes: S11, Provide current collector 16; S12. The third active slurry and the first insulating slurry are coated on the current collector 16, and the first insulating slurry has a first non-straight edge 180 away from the third active slurry. The first non-straight edge 180 includes a first protrusion 1810 and a first concave portion 1811 arranged alternately along the second direction y. The first direction x, the second direction y and the thickness direction z are perpendicular to each other. S13. At least a portion of the fourth active slurry is coated onto the side of the third active slurry away from the current collector 16.

[0273] In some embodiments, a method for manufacturing a battery cell 10 is provided, which can manufacture a first electrode 15 in the battery cell 10 described above. The first electrode 15 can be a positive electrode.

[0274] The third active slurry is a fluid-like active material that, after drying, forms a third active material layer. The fourth active slurry is also a fluid-like active material that, after drying, forms a fourth active material layer. Both the third and fourth active slurries may contain positive electrode active materials.

[0275] After drying, the first insulating grout can form the first insulating layer.

[0276] Optionally, in step S12, after the first insulating slurry is coated on the current collector 16, a first non-straight edge 180 can be formed at the edge of the first insulating slurry away from the third active slurry by means of high-precision die cutting, laser cutting or digital spraying mask.

[0277] Optionally, in step S12, during the process of coating the insulating slurry on the current collector 16, the coating die gasket can be optimized and the die gasket can be designed to correspond to the shape of the first non-straight edge 180, so that the active slurry is intermittently distributed at the die outlet, so that after the first insulating slurry dries to form the first insulating layer, the edge of the first insulating layer is formed as the first non-straight edge 180.

[0278] Optionally, in step S12, during the process of coating the first insulating slurry on the current collector 16, the zebra coating method can be used. By adjusting the coating pressure in the mold cavity and the Teflon treatment on both sides of the mold cavity, an uneven coating thickness can be achieved in the edge area of ​​the first insulating slurry, thereby indirectly forming the first non-straight edge 180.

[0279] Optionally, in step S12, before applying insulating paste to the current collector 16, adhesive tape corresponding to the first non-straight edge 180 is provided on the edge of the current collector 16, then the first insulating paste is applied, and the first non-straight edge 180 is formed after removing the adhesive tape.

[0280] Optionally, during the coating of insulating slurry onto the current collector 16, edge processing control can be used to reduce or increase the surface tension of the slurry during drying to control the flowability of the slurry to form a first non-straight edge 180.

[0281] In the above scheme, by making the first insulating slurry locally concave at the edge away from the first active slurry and forming a first non-straight edge 180, it can effectively provide a space for the active slurry to migrate in the first direction x under external force (such as roller pressure) or adhesion force, improve the edge thickness uniformity of the positive electrode sheet in the first direction x, reduce the problem of poor welding caused by inconsistent root thickness during positive electrode tab welding, and enable the battery cell 10 to have a high yield and reliability.

[0282] According to some embodiments of this application, S13, coating at least a portion of the fourth active slurry onto the side of the third active slurry away from the current collector 16 includes: A fourth active slurry and a second insulating slurry are coated on a third active slurry and a first insulating slurry. The third active slurry is located between the fourth active slurry current collector 16, and at least a portion of the first insulating slurry is located between the second insulating slurry and the current collector 16, such that the second insulating slurry has a second non-straight edge 190 away from the fourth active slurry. The second non-straight edge 190 includes a second convex portion 1910 and a second concave portion 1911 alternately arranged along a second direction y.

[0283] Some embodiments of this application provide a single battery cell 10; please refer to [link to relevant documentation]. Figures 3-9 The battery cell 10 includes a first electrode 15, which includes a current collector 16 and a film layer 17. The film layer 17 is disposed on at least one side of the current collector 16 in the thickness direction z. The film layer 17 includes a first film layer 18 and a second film layer 19.

[0284] Optionally, the first electrode 15 can be a negative electrode or a positive electrode. Taking the first electrode 15 as a negative electrode as an example: the first film layer 18 includes artificial graphite and is disposed on the current collector 16; the second film layer 19 includes silicon-carbon composite material and at least a portion of the second film layer 19 is located on the side of the first film layer 18 away from the current collector 16.

[0285] Along a first direction x, a first film layer 18 has a first non-straight edge 180, and a second film layer 19 has a second non-straight edge 190. The first non-straight edge 180 includes a plurality of first protrusions 1810 and a plurality of first recesses 1811 alternately arranged along a second direction y. The outline of the first protrusions 1810 is triangular, arc-shaped, or trapezoidal. The second non-straight edge 190 includes a plurality of second protrusions 1910 and a plurality of second recesses 1911 alternately arranged along the second direction y. The outline of the second protrusions 1910 is triangular, arc-shaped, or trapezoidal.

[0286] In some embodiments, the dimension of the first protrusion 1810 along the second direction y is greater than the dimension of the second protrusion 1910 along the second direction y, the first protrusion 1810 extends beyond the second protrusion 1910 along the first direction x, and a portion of the second protrusion 1910 is located in the first recess 1811.

[0287] In the battery cell 10 provided above, the two edges of the first film layer 18 and the second film layer 19 located on the same side along the first direction x are partially concave to form a first non-straight edge 180 and a second non-straight edge 190, respectively. On the one hand, during the manufacturing process of the battery cell 10, the concave regions of the first film layer 18 and the second film layer 19 can provide a space for the active material of the film layer 17 to migrate in the first direction x under external force (such as roller pressure), thereby improving the edge thickness uniformity of the film layer 17 in the first direction x and reducing the problem of poor welding caused by inconsistent root thickness during electrode welding, thus enabling the battery cell 10 to have a high yield and reliability. On the other hand, after the battery cell 10 has undergone a certain number of charge and discharge cycles, the concave regions of the first film layer 18 and the second film layer 19 can provide a space for the active material of the film layer 17 to migrate in the first direction x due to expansion, thereby reducing the amount of expansion of the active material along the first direction x, thus reducing the risk of cracking at the welding point between the electrode and the current collector 13 due to excessive expansion of the active material, thereby enabling the battery cell 10 to have high reliability, and consequently enabling the battery device 100 to have high reliability.

[0288] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, comprising a first electrode, the first electrode comprising a current collector and a film layer, the film layer being disposed on at least one side in the thickness direction of the current collector, characterized in that, The membrane layer includes a first membrane layer and a second membrane layer. Along the thickness direction of the current collector, at least a portion of the first membrane layer is located between the second membrane layer and the current collector. The first membrane layer has a first non-straight edge in a first direction. The first non-straight edge includes alternating first protrusions and first concave portions along a second direction. The first direction, the second direction, and the thickness direction are perpendicular to each other. The second film layer has a second non-straight edge in the first direction, the second non-straight edge and the first non-straight edge are disposed on the same side, and the second non-straight edge includes a second protrusion and a second concave portion arranged alternately along the second direction; Along the second direction, the first protrusion and the second protrusion are misaligned; The current collector includes a body and at least one first tab, the body having a third edge in the first direction, at least one first tab extending from the third edge, and the first non-straight edge being the edge of the first film layer near the first tab.

2. The battery cell according to claim 1, characterized in that, The outline of the first protrusion is triangular, arc-shaped, or trapezoidal.

3. The battery cell according to claim 1, characterized in that, The first non-straight edge includes a plurality of first protrusions and a plurality of first recesses.

4. The battery cell according to claim 1, characterized in that, Along the second direction, the distance between two adjacent first protrusions is different from the distance between two adjacent second protrusions.

5. The battery cell according to claim 1, characterized in that, Along the first direction, the maximum dimension L of the first protrusion satisfies: 0.5mm≤L≤3mm.

6. The battery cell according to claim 1, characterized in that, Along the first direction, at least a portion of the first film layer extends beyond the second film layer.

7. The battery cell according to claim 6, characterized in that, Along the first direction, the second film layer extends beyond the first recess.

8. The battery cell according to claim 6, characterized in that, A portion of the first protrusion is located between the second film layer and the current collector, and another portion of the first protrusion extends beyond the second film layer along the first direction.

9. The battery cell according to any one of claims 1-8, characterized in that, The first electrode is a negative electrode, the first film layer is a first active material layer, and the second film layer is a second active material layer.

10. The battery cell according to claim 9, characterized in that, The expansion coefficient of the first active material layer is smaller than that of the second active material layer.

11. The battery cell according to claim 9, characterized in that, The first active material layer is made of graphite, and the second active material layer is made of silicon-carbon composite material.

12. The battery cell according to claim 11, characterized in that, The mass of the first active material layer is greater than the mass of the second active material layer.

13. The battery cell according to claim 12, characterized in that, The mass ratio of the first active material layer to the second active material layer is greater than 1 and less than 9.

14. The battery cell according to any one of claims 1-8, characterized in that, The first electrode is a positive electrode, the first film layer includes a third active material layer and a first insulating layer that are interconnected, the first insulating layer and the third active material layer are arranged along the first direction, the first insulating layer has the first non-straight edge, and the second film layer includes a fourth active material layer.

15. The battery cell according to claim 14, characterized in that, The second membrane layer includes a second insulating layer connected to the fourth active material layer. Along the thickness direction, the third active material layer is located between the fourth active material layer and the current collector, and at least a portion of the first insulating layer is located between the second insulating layer and the current collector.

16. The battery cell according to claim 15, characterized in that, The expansion coefficient of the third active material layer is greater than that of the fourth active material layer.

17. The battery cell according to claim 15, characterized in that, The active material in the third active material layer includes ternary materials, and the active material in the fourth active material layer includes lithium iron phosphate.

18. The battery cell according to claim 15, characterized in that, The mass of the fourth active material layer is greater than the mass of the third active material layer.

19. The battery cell according to claim 18, characterized in that, The mass ratio of the fourth active material layer to the mass of the third active material layer is greater than 1 and less than 9.

20. The battery cell according to claim 1, characterized in that, The battery cell is in the shape of a parallelepiped and includes a current collector and an electrode assembly. The first electrode tab is electrically connected to the current collector. The first membrane layer includes a first part and a second part. The first part is disposed on the main body, and the second part is disposed on the first tab. The first non-straight edge is the edge of the second part that is opposite to the first part.

21. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-20.

22. An electrical appliance, characterized in that, Includes the battery cell according to any one of claims 1-20, or the battery device according to claim 21.

23. A method for manufacturing a single battery cell, characterized in that, include: A current collector is provided, the current collector comprising a body and at least one first electrode tab, the body having a third edge in a first direction, and at least one first electrode tab extending from the third edge; The first active slurry is coated on at least one side of the current collector along its thickness direction, and the first active slurry has a first non-straight edge in the first direction. The first non-straight edge is the edge of the first active slurry near the first tab. The first non-straight edge includes a first protrusion and a first concave portion arranged alternately along a second direction. The first direction, the second direction and the thickness direction are perpendicular to each other. At least a portion of the second active slurry is coated on the side of the first active slurry away from the current collector, such that the second active slurry has a second non-straight edge in a first direction. The second non-straight edge is disposed on the same side as the first non-straight edge. The second non-straight edge includes a second protrusion and a second concave portion arranged alternately along the second direction. Along the second direction, the first protrusion and the second protrusion are staggered.

24. A method for manufacturing a single battery cell, characterized in that, include: A current collector is provided, the current collector comprising a body and at least one first electrode tab, the body having a third edge in a first direction, and at least one first electrode tab extending from the third edge; A third active slurry and a first insulating slurry are coated on at least one side of the current collector along its thickness direction, such that the first insulating slurry has a first non-straight edge away from the third active slurry along a first direction. The first non-straight edge is the edge of the third active slurry near the first tab. The first non-straight edge includes a first protrusion and a first concave portion arranged alternately along a second direction. The first direction, the second direction, and the thickness direction are perpendicular to each other. At least a portion of the fourth active slurry is coated on the side of the third active slurry away from the current collector. The fourth active slurry and the second insulating slurry are coated on the third active slurry and the first insulating slurry. The third active slurry is located between the fourth active slurry and the current collector. At least a portion of the first insulating slurry is located between the second insulating slurry and the current collector. The second insulating slurry has a second non-straight edge away from the fourth active slurry. The second non-straight edge includes a second convex portion and a second concave portion arranged alternately along the second direction. Along the second direction, the first convex portion and the second convex portion are misaligned.

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