Battery cell and method for manufacturing the same, battery device, electric device, and energy storage device

Abstract

The application relates to the field of batteries, and provides a battery monomer, a preparation method of the battery monomer, a battery device, a power utilization device and an energy storage device, which are used for improving the safety and stability of the battery monomer. The battery monomer comprises a battery shell, a cavity in the battery shell, and an electrolyte in the cavity; an electric core assembly is located in the cavity, and the electric core assembly is located in the electrolyte; the electric core assembly comprises a positive plate, a diaphragm and a negative plate; the negative plate comprises a negative current collector and a carbon-silicon active layer; an elastic layer is located on the carbon-silicon active layer, the elastic layer comprises a conductive framework and a carbon layer, the conductive framework is located in the carbon layer, and the conductive framework is constructed in a honeycomb structure by a plurality of hexagonal copper metal units.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell and its preparation method, a battery device, an electrical device, and an energy storage device. Background Technology

[0002] With the rapid development of the energy storage market, energy storage cells are undergoing accelerated upgrades and iterations. Currently, cell products are developing towards larger capacity and higher energy density. The main performance of cell products depends on the performance of the positive electrode material constituting the positive electrode and the negative electrode material constituting the negative electrode. Traditionally, graphite is the negative electrode material, but traditional graphite negative electrode materials in lithium-ion batteries suffer from low diffusion rate and poor rate performance. Volume expansion leads to the rupture of the SEI film (solid electrolyte interface / membrane), limiting cycle life.

[0003] Based on this, in addition to developing positive and negative electrode materials with higher specific capacity, in cell design, the energy density of the cell is often improved by increasing the coating density and compaction density of the electrode. However, this will significantly increase the electrochemical impedance of the electrode. In particular, for the negative electrode, the increase in the electrochemical impedance of the electrode will increase the risk of lithium plating during the charging process, leading to the capacity decay of the cell.

[0004] Currently, the challenge lies in how to reduce the electrochemical impedance of the electrode and improve its safety while altering its performance—that is, improving the capacity of both positive and negative electrode materials. Summary of the Invention

[0005] This application provides a battery cell and its preparation method, a battery device, an electrical device, and an energy storage device, which at least help improve the safety and stability of the battery cell.

[0006] According to some embodiments of this application, one aspect of this application provides a battery cell, including: a battery casing having a cavity inside the battery casing containing an electrolyte; a cell assembly located within the cavity and within the electrolyte; the cell assembly including a positive electrode, a separator, and a negative electrode, wherein the negative electrode includes: a negative current collector and a silicon carbide active layer; an elastic layer located on the silicon carbide active layer, the elastic layer including a conductive framework and a carbon layer, the conductive framework being located within the carbon layer, the conductive framework being constructed from multiple hexagonal copper metal units in a honeycomb structure.

[0007] In some embodiments, the elastic layer includes 2 to 3 layers of the conductive framework; the thickness of the conductive framework ranges from 100 nm to 200 nm.

[0008] In some embodiments, the ratio of the unfolded area of ​​the conductive framework to that of the carbon layer is 1:(5~8).

[0009] In some embodiments, the side length of the copper metal unit ranges from 50 μm to 80 μm.

[0010] In some embodiments, the system further includes a plasma active layer located between the silicon carbide active layer and the elastic layer.

[0011] In some embodiments, the thickness of the plasma active layer is 1 nm to 100 nm.

[0012] According to some embodiments of this application, another aspect of this application provides a method for preparing a battery cell, comprising: forming a negative electrode sheet, the negative electrode sheet comprising: a negative electrode current collector and a silicon carbide active layer; an elastic layer, the elastic layer being located on the silicon carbide active layer, the elastic layer comprising a conductive framework and a carbon layer, the conductive framework being located within the carbon layer, the conductive framework being constructed of a plurality of hexagonal copper metal units in a honeycomb structure; providing a positive electrode sheet and a separator; sequentially stacking the negative electrode sheet, separator and positive electrode sheet, and obtaining a cell assembly by winding or stacking the negative electrode sheet, placing the cell assembly into a battery casing, injecting electrolyte into the battery casing, and then encapsulating it to obtain a battery cell.

[0013] In some embodiments, the process steps for forming the negative electrode sheet include: providing a negative electrode current collector; forming a silicon-carbon active layer located on the surface of the negative electrode current collector; performing plasma activation treatment on the silicon-carbon active layer to form an uneven structure on the surface of the silicon-carbon active layer; forming an initial elastic film having an initial conductive framework composed of copper atoms and carbon atoms, the carbon atoms being located within the initial conductive framework and encapsulating silicon particles within the silicon-carbon active layer; performing a conditioning treatment on the initial elastic film to cause the copper atoms in the initial conductive framework to self-assemble into hexagonal copper metal units and construct a honeycomb structure; and constructing the carbon layer with the carbon atoms.

[0014] In some embodiments, the process steps for forming the initial elastic film include: sputtering copper atoms onto the silicon-carbon active layer using a copper target to form an initial conductive framework; and sputtering carbon atoms onto the silicon-carbon active layer using a carbon target to form carbon atoms located within the initial conductive framework, wherein the carbon atoms encapsulate silicon particles within the silicon-carbon active layer.

[0015] In some embodiments, the process steps for regulating the initial elastic membrane include: rotating the initial elastic membrane at a constant speed of 5 rpm to 20 rpm, using centrifugal force and plasma irradiation to drive copper atoms to periodically nucleate, so that the copper atoms self-assemble into hexagonal copper metal units, and constructing a honeycomb structure.

[0016] In some embodiments, the sputtering power of sputtering the silicon-carbon active layer with a copper target to form copper atoms is a first power; the sputtering power of sputtering the silicon-carbon active layer with a carbon target to form carbon atoms is a second power, and the ratio of the second power to the first power is 1.3 to 20.

[0017] In some embodiments, the first power is 100W~180W; the second power is 270W~350W.

[0018] In some embodiments, after plasma activation treatment of the silicon carbide active layer, the process includes: evacuating to a pressure ≤ 5 × 10⁻⁶. -4 Pa; introduce argon gas to 0.3 Pa~0.8 Pa, and pre-sputter through copper and carbon targets for 2 min~5 min.

[0019] According to some embodiments of this application, another aspect of this application provides a battery device, including a battery cell as described in any of the above embodiments or a battery cell prepared by a method described in any of the above embodiments, the battery device including one or more of a battery module, a battery pack, and an energy storage battery.

[0020] According to some embodiments of this application, another aspect of this application provides an electrical device, including a battery device as described in the above embodiments, the battery device being used to provide electrical energy.

[0021] According to some embodiments of this application, another aspect of this application provides an energy storage device, including a battery device as described in the above embodiments, the battery device being used to store electrical energy.

[0022] The technical solution provided in this application has at least the following advantages:

[0023] The negative electrode sheet provided in this application embodiment includes a silicon-carbon active layer composed of silicon-carbon composite material. The silicon-carbon active layer, as a silicon-carbon negative electrode, has advantages such as good stability, small volume change and excellent conductivity, thereby improving the expansion and failure problems of silicon-based negative electrode materials.

[0024] The elastic layer, located on top of the silicon carbide active layer, consists of a conductive framework (copper metal units in a honeycomb structure) and a carbon layer. Its buffering effect is primarily based on the following mechanisms: First, the conductive framework is constructed from multiple hexagonal copper metal units in a honeycomb structure, which possesses high specific strength, high toughness, and excellent energy absorption characteristics. When the silicon carbide active layer undergoes volume changes during lithium-ion insertion / extraction, the honeycomb structure can absorb and disperse stress through elastic deformation, acting like a spring to buffer mechanical impacts. Specifically, the isotropic nature of the honeycomb structure allows it to uniformly withstand multi-directional stresses, reducing stress concentration points and effectively suppressing silicon particle breakage and electrode layer peeling. Copper itself has good ductility and conductivity, ensuring that the elastic layer does not break during buffering while maintaining the continuity of the electron conduction path. Second, the carbon layer enhances interface stability and adaptability: the carbon layer is encased within the conductive framework. Carbon materials typically possess good flexibility and lubricity, further adapting to the volume changes of silicon. The carbon layer can fill the gaps in the honeycomb structure, forming a more continuous buffer layer and reducing the direct contact pressure between the silicon carbide active layer and the separator. The carbon layer also helps stabilize the formation of the SEI film because carbon materials have good compatibility with the electrolyte, which can reduce side reactions and thus alleviate interfacial instability caused by volume changes.

[0025] The elastic layer, combined with the silicon carbide active layer, forms a "stress buffer." During lithium-ion insertion / extraction, the expansion of silicon is first absorbed by the elastic layer, preventing stress from being directly transmitted to the current collector and separator. During contraction, the elastic restoring force of the elastic layer maintains the tightness of the electrode structure, preventing electrode loosening. This design is similar to adding a flexible layer between a rigid material (silicon) and a rigid component (such as the negative electrode current collector), thereby improving the electrode's resilience. By buffering stress and deformation, the elastic layer reduces the mechanical degradation of the silicon carbide active layer, delaying capacity decay and allowing the battery cell to withstand more charge-discharge cycles. The elastic layer prevents damage to the electrode structure and reduces the risk of internal short circuits. The conductive framework ensures good electronic conduction, avoiding the impedance increase caused by the buffer layer, allowing the battery to maintain stable performance even at high rates.

[0026] During prolonged charging, the elastic layer of this battery cell absorbs the expansion force of silicon, preventing excessive compression of the separator and significantly reducing the risk of separator deformation or damage due to stress accumulation. Secondly, by stabilizing the SEI film, interfacial side reactions and lithium consumption are reduced, ensuring long-term capacity retention and efficient operation. Furthermore, this fundamentally solves the short lifespan limitation of silicon anodes, allowing the battery to stably undergo complete and drastic volume expansion and contraction during long-term charge and discharge processes. It can withstand deep cycling for several years, once a day, significantly improving cycle life and meeting the stringent requirements for cycle count in long-term energy storage. For example, it can be applied to 5h, 6h, and 8h energy storage scenarios. Long-term energy storage refers to continuous discharge at rated power for 4 hours or even longer, or large-scale, low-cost energy storage for several days or months. This solution helps improve the quality retention rate of battery products during warehousing and transportation, as well as the performance of end-user equipment after long-term idle periods. Attached Figure Description

[0027] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A cross-sectional view of a battery cell provided in an embodiment of this application;

[0029] Figure 2 A cross-sectional view of a negative electrode sheet provided in an embodiment of this application;

[0030] Figure 3 This is another cross-sectional view of a negative electrode sheet provided in an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 100, Negative current collector; 101, Silicon carbide active layer; 102, Plasma active layer; 11, Elastic layer; 110, Conductive framework; 111, Copper metal unit; 120, Carbon layer; 1, Positive electrode sheet; 2, Negative electrode sheet; 3, Separator. Detailed Implementation

[0033] As can be seen from the background technology, current battery cells have safety and stability issues.

[0034] Analysis reveals that one of the safety issues currently existing in battery cells lies in the fact that while silicon, as an anode active material, has a high theoretical capacity (approximately 4200 mAh / g), it undergoes drastic volume changes during charge and discharge (shrinking during lithium delithiation and expanding during lithium insertion, with volume changes exceeding 300%). These repeated volume changes lead to: mechanical stress concentration: high stress is generated inside and at the interface of silicon particles, easily causing particle breakage and pulverization, resulting in the loss of active material. Electrode structure damage: volume changes can cause electrode coating detachment and current collector deformation, compromising electrode integrity. Interface instability: repeated changes in the solid-liquid interface between silicon and the electrolyte easily lead to the formation of an unstable SEI film, exacerbating capacity decay. During long-term charge and discharge processes, silicon materials undergo complete and drastic volume expansion and contraction. This "breathing effect," after thousands of repetitions, causes cumulative and irreversible damage to the electrode structure, a major cause of early failure in traditional silicon-carbon anode batteries for long-term energy storage applications.

[0035] This application provides a battery cell that forms a "stress buffer" by incorporating a silicon-carbon active layer and an elastic layer. During lithium-ion insertion / extraction, the expansion of silicon is first absorbed by the elastic layer, preventing stress from being directly transmitted to the current collector and separator. During contraction, the elastic restoring force of the elastic layer maintains the tightness of the electrode structure, preventing electrode loosening. This design is similar to adding a flexible layer between a rigid material (silicon) and a rigid component (such as the negative electrode current collector), thereby improving the electrode's resilience. By buffering stress and deformation, the elastic layer reduces the mechanical degradation of the silicon-carbon active layer, delays capacity decay, and allows the battery cell to withstand more charge-discharge cycles. The elastic layer prevents damage to the electrode structure and reduces the risk of internal short circuits. The conductive framework ensures good electronic conduction, avoids the impedance increase caused by the buffer layer, and allows the battery to maintain stable performance even at high rates.

[0036] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0039] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0040] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0041] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0042] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0043] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0044] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0045] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0046] According to some embodiments of this application, one aspect of this application provides a battery cell for improving the safety of battery cells.

[0047] Figure 1 A cross-sectional view of a battery cell provided in an embodiment of this application; Figure 2 This is a cross-sectional view of a negative electrode sheet provided in an embodiment of this application.

[0048] refer to Figure 1 and Figure 2 The battery cell includes: a battery casing with a cavity inside containing an electrolyte; a cell assembly located inside the cavity and within the electrolyte; the cell assembly includes a positive electrode 1, a separator 3, and a negative electrode 2, wherein the negative electrode 2 includes: a negative current collector 100 and a silicon carbide active layer 101; an elastic layer 11 located on the silicon carbide active layer 101, the elastic layer 11 including a conductive framework 110 and a carbon layer 120, the conductive framework 110 being located within the carbon layer 120, the conductive framework 110 being constructed from multiple hexagonal copper metal units 111 in a honeycomb structure.

[0049] The negative electrode sheet provided in this application embodiment includes a silicon-carbon active layer 101 composed of silicon-carbon composite material. The silicon-carbon active layer 101, as a silicon-carbon negative electrode, has advantages such as good stability, small volume change and excellent conductivity, thereby improving the expansion and failure problems of silicon-based negative electrode materials.

[0050] The elastic layer 11 is located on the silicon carbide active layer 101 and consists of a conductive framework 110 (a honeycomb-structured copper metal unit 111) and a carbon layer 120. Its buffering effect is mainly based on the following mechanisms: First, the conductive framework 110 is constructed from multiple hexagonal copper metal units 111 in a honeycomb structure. The honeycomb structure has high specific strength, high toughness, and good energy absorption characteristics. When the silicon carbide active layer undergoes volume changes during lithium-ion insertion / extraction, the honeycomb structure can absorb and disperse stress through elastic deformation, buffering mechanical impacts like a spring. Specifically, the isotropic nature of the honeycomb structure allows it to uniformly withstand multi-directional stresses, reducing stress concentration points and effectively suppressing silicon particle breakage and electrode layer peeling. Copper itself has good ductility and conductivity, ensuring that the elastic layer 11 will not break during buffering while maintaining the continuity of the electron conduction path. Second, the carbon layer 120 enhances interface stability and adaptability: the carbon layer 120 is wrapped within the conductive framework 110. Carbon materials typically have good flexibility and lubricity, further adapting to the volume changes of silicon. The carbon layer 120 can fill the gaps in the honeycomb structure, forming a more continuous buffer layer and reducing the direct contact pressure between the silicon carbide active layer and the separator. The carbon layer 120 also helps stabilize the formation of the SEI film because carbon materials have good compatibility with the electrolyte, reducing side reactions and thus mitigating interfacial instability caused by volume changes.

[0051] The elastic layer 11, combined with the silicon carbide active layer 101, forms a "stress buffer." During lithium-ion insertion / extraction, the expansion of silicon is first absorbed by the elastic layer 11, preventing stress from being directly transmitted to the current collector and separator. During contraction, the elastic restoring force of the elastic layer 11 maintains the tightness of the electrode structure, preventing the electrode from loosening. This design is similar to adding a flexible layer between a rigid material (silicon) and a rigid component (such as the negative electrode current collector 100), thereby improving the electrode's resilience. By buffering stress and deformation, the elastic layer 11 reduces the mechanical degradation of the silicon carbide active layer 101, delaying capacity decay and allowing the battery cell to withstand more charge-discharge cycles. The elastic layer 11 prevents damage to the electrode structure and reduces the risk of internal short circuits. The conductive framework 110 ensures good electronic conduction, avoiding the impedance increase caused by the buffer layer, enabling the battery to maintain stable performance even at high rates.

[0052] During prolonged charging, the elastic layer 11 of this battery cell absorbs the expansion force of silicon, preventing excessive compression of the separator and greatly reducing the risk of separator deformation or damage due to stress accumulation. Secondly, by stabilizing the SEI film, interfacial side reactions and lithium consumption are reduced, ensuring long-term capacity retention and efficient operation. Furthermore, this fundamentally solves the short lifespan limitation of silicon anodes, allowing the battery to stably undergo complete and drastic volume expansion and contraction during long-term charge and discharge processes. It can withstand deep cycling for several years, once a day, significantly improving the battery's cycle life and meeting the stringent requirements for cycle count in long-term energy storage.

[0053] The battery cell described above will be explained in detail below with reference to the accompanying drawings.

[0054] Based on their shape, the prepared battery cells can be classified into square cells, round cells, or pouch cells. Based on their capacity, battery cells can be classified into models such as 50Ah, 100Ah, 150Ah, 200Ah, 280Ah, 306Ah, 314Ah, 500+Ah, 800+Ah, and 1000+Ah. Based on the chemical composition and working principle of the battery cell components, battery cells can be classified as lithium-ion batteries, lead-acid batteries, sodium-ion batteries, or nickel-metal hydride batteries. This application uses a lithium-ion battery preparation method as an example. Those skilled in the art can replace the lithium ions in the positive electrode 1, negative electrode 2, and electrolyte with corresponding metal ions according to actual needs. For example, in sodium-ion batteries, the lithium transition metal oxide of the positive electrode active material can be replaced with any of the following: a layered metal oxide (e.g., NaFeO2), a polyanionic compound (NaFePO4), or a Prussian blue compound system (e.g., NaMnFe(CN)6-zH2O), and the electrolyte can be replaced with any of the following: an organic liquid electrolyte, a solid composite electrolyte, or a solid electrolyte.

[0055] refer to Figure 1 Positive electrode 1 serves as the cathode in the redox reaction. During discharge, the positive electrode material (lithium salt material) releases lithium ions (Li) through a chemical reaction. + ) and electrons (e - During charging, lithium ions are reabsorbed.

[0056] The positive electrode 1 includes a positive current collector and a positive active layer. The positive current collector can be aluminum foil. Aluminum foil is cheaper than copper foil. A dense oxide film is formed on the surface of the aluminum foil, and the oxide film is very thin, which can improve the corrosion resistance of the aluminum foil, and electrons can achieve electrical conduction through the tunneling effect.

[0057] In some embodiments, the current collector of the positive electrode 1 can also be a composite current collector, which includes three stacked layers: an organic material in the middle layer, and copper-plated and aluminum-plated layers on the top and bottom. The organic material is PET (polyterephthalate), PP (polypropylene), PI (polyimide), etc.

[0058] The positive electrode active material within the positive electrode active layer is an energy storage material, typically composed of metal oxides, metal sulfides, or polymers. Its main function is to chemically react with lithium ions at the negative electrode during battery charging, thereby storing lithium ions, increasing the lithium ion concentration, and allowing the positive electrode to release charge current. Simultaneously, during battery discharge, the lithium ions stored in the positive electrode active material move towards the negative electrode, reacting with the negative electrode material, creating a potential difference between the positive and negative electrodes, and thus generating current output.

[0059] The negative electrode 2 serves as the anode in the redox reaction. During discharge, the negative electrode material (such as graphite or silicon-based materials) accepts and stores lithium ions; during charging, it releases lithium ions.

[0060] The negative electrode includes a negative electrode current collector 100, which can be a copper foil. Copper foil has low conductivity, allowing for high electron transport capability, and its weak lithium intercalation capability captures fewer lithium ions, thus effectively reducing lithium ion loss. In other embodiments, the negative electrode current collector 100 can also be a foamed copper current collector, a copper mesh current collector, or a three-dimensional nano-copper array current collector.

[0061] In some embodiments, the negative electrode current collector 100 can be a composite current collector, including a polymer material layer and a metal plating layer. The metal plating layer is located on the upper and lower sides of the polymer material layer. The polymer material layer is PET (polyterephthalate), PP (polypropylene), PI (polyimide), etc., and the metal plating layer is a copper layer.

[0062] In some embodiments, the negative electrode current collector 100 can also be a carbon-based current collector, i.e., a conductive carbon layer is formed on the copper foil. The conductive carbon layer can serve as a protective layer to effectively protect the current collector, preventing corrosion of the metal current collector and thus improving its lifespan. Secondly, the conductive carbon layer itself has low resistivity, thus minimizing electrical losses. The material of the conductive carbon layer can be flake graphite, spherical graphite, carbon nanotubes, graphene, etc.

[0063] The silicon-carbon active layer 101 is located on the negative electrode current collector 100. The silicon-carbon active layer 101 consists of negative electrode active material particles, which serve as the carrier for the oxidation reaction within the battery cell. The silicon-carbon active layer 101 is a silicon-carbon composite material formed by combining carbon materials with existing silicon-based negative electrode materials. As a silicon-carbon negative electrode, this composite material offers advantages such as good stability, small volume change, and excellent conductivity, thereby mitigating the expansion and failure issues associated with silicon-based negative electrode materials.

[0064] Silicon-carbon anodes refer to a mixture of nano-silicon and carbon materials. By reducing the particle size of the silicon-based material to the nanoscale, more porosity can be created to buffer the stress and deformation generated during the lithium-ion insertion / extraction process. The preparation of silicon-carbon anodes requires first preparing nano-silicon particles, with the outermost layer being a carbon coating, forming a core-shell structure.

[0065] In some embodiments, the negative electrode includes an elastic layer 11 located on the surface of the silicon carbide active layer 101, which is used to buffer the stress and deformation generated in silicon during the lithium ion insertion / extraction process.

[0066] The specific mechanism can be described as follows: The conductive framework 110 is constructed from multiple hexagonal copper metal units 111 in a honeycomb structure. This structure is known in materials science to have high specific strength, high toughness, and good energy absorption characteristics. When the carbon silicon active layer undergoes volume changes during the lithium ion insertion and extraction process, the honeycomb structure can absorb and disperse stress through elastic deformation, just like a spring to buffer mechanical impact.

[0067] First, the conductive framework 110 is constructed from multiple hexagonal copper metal units 111 in a honeycomb structure, which possesses high specific strength, high toughness, and good energy absorption characteristics. When the silicon carbide active layer 101 undergoes volume changes during lithium-ion insertion / extraction, the honeycomb structure can absorb and disperse stress through elastic deformation, acting like a spring to buffer mechanical impacts. Specifically, the isotropic nature of the honeycomb structure allows it to uniformly withstand multi-directional stresses, reducing stress concentration points and effectively suppressing silicon particle breakage and electrode layer peeling. Copper itself has good ductility and conductivity, ensuring that the elastic layer 11 does not break during buffering while maintaining the continuity of the electron conduction path. Second, the carbon layer 120 enhances interface stability and adaptability: the carbon layer 120 is encased within the conductive framework 110. Carbon materials typically possess good flexibility and lubricity, further adapting to the volume changes of silicon. The carbon layer 120 can fill the gaps in the honeycomb structure, forming a more continuous buffer layer and reducing the direct contact pressure between the silicon carbide active layer 101 and the separator. The carbon layer 120 also helps stabilize the formation of the SEI film because carbon materials have good compatibility with the electrolyte, which can reduce side reactions and thus alleviate interfacial instability caused by volume changes.

[0068] In some embodiments, the elastic layer 11 includes 2 to 3 conductive frameworks 110. The multi-layered conductive framework 110 can form a multi-layered buffer layer. These multiple layers, composed of a honeycomb structure, can absorb and disperse stress through elastic deformation at multiple angles and dimensions, thereby minimizing the direct contact pressure between the silicon carbide active layer 101 and the separator, and improving the stability and safety of the battery cell. Secondly, if the conductive framework 110 is too thin, the overall conductivity of the conductive framework 110 will be insufficient; if it is too thick, the porosity of the honeycomb structure of the hexagonal copper metal units 111 will be reduced.

[0069] In some embodiments, the elastic layer 11 can be a single conductive skeleton 110, a double conductive skeleton 110, or a triple conductive skeleton 110.

[0070] In some embodiments, the thickness of the conductive framework 110 ranges from 100 nm to 200 nm. If the elastic layer 11 is too thick, its overall rigidity will increase. While the supporting force may be stronger, the flexibility will decrease. It may not be able to adapt well to the frequent and drastic volume changes of the silicon-carbon layer 120, and may even crack due to stress, or transfer more stress to the underlying silicon-carbon active layer 101, thus reducing the buffering effect. At the same time, an excessively thick inactive layer will reduce the energy density of the battery. If the elastic layer 11 is too thin, its mechanical strength may be insufficient. When the silicon material expands, the thin layer is easily overstretched and cracked, losing its continuity, and thus failing to effectively constrain and buffer volume changes. The thickness range of 100 nm to 200 nm for the conductive framework 110 ensures that the elastic layer 11 has sufficient mechanical strength and toughness to withstand cyclic stress, while maintaining excellent flexibility, and can reversibly deform as the silicon expands and contracts like a tough and elastic "nanoscale spring pad", thereby providing continuous and effective buffering protection.

[0071] Specifically, the thickness of the conductive framework 110 can be 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200nm.

[0072] In some embodiments, the side length of the hexagonal copper metal unit 111 ranges from 50 μm to 80 μm. This range ensures that each hexagonal unit possesses suitable stiffness and flexibility. At this size, when internal pressure increases, the frame of the copper skeleton can undergo slight elastic bending and stretching, much like stretching a hexagonal spring. This deformation process itself provides an effective energy (stress) absorption and release process. If the size is too small, the unit is too rigid and difficult to deform; if the size is too large, the unit is too flexible and lacks sufficient constraint. The side length range of the hexagonal copper metal unit 111 is also greater than the expansion displacement of the silicon particles (a single particle expands by approximately 2 μm to 3 μm during charging and discharging), allowing for stress release space. The side length of the hexagonal copper metal unit 111 can be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, or 80 μm.

[0073] It should be noted that the thickness of the conductive framework 110 refers to the thickness of the copper metal unit 111 within a microscopic angle. The side length of the copper metal unit 111 refers to the range of side lengths of the hexagon formed by the copper metal units 111, and the hexagon can be a standard regular hexagon or a near-perfect hexagon.

[0074] The carbon layer 120 enhances interfacial stability and adaptability: Encased within the conductive framework 110, the carbon layer 120, with its inherent flexibility and lubricity, further adapts to volume changes in silicon. The carbon layer 120 fills the voids in the honeycomb structure, forming a more continuous buffer layer and reducing the direct contact pressure between the carbon-silicon active layer and the separator. Furthermore, the carbon layer 120 contributes to stabilizing SEI film formation because the carbon material exhibits good compatibility with the electrolyte, reducing side reactions and mitigating interfacial instability caused by volume changes.

[0075] In some embodiments, the carbon layer 120 can be made of either graphite (natural graphite, artificial graphite, or mesophase carbon spheres) or other carbon-based materials (hard carbon, soft carbon, and graphene). In other embodiments, the carbon layer 120 can be made of composite materials, such as materials with amorphous carbon as the matrix and a small amount of graphene or carbon nanotubes, which can simultaneously achieve excellent encapsulation, ultra-high conductivity, and superior mechanical strength, providing top-level protection for the long-term cycle stability of the battery.

[0076] In some embodiments, the unfolded area ratio of the conductive skeleton 110 to the carbon layer 120 is 1:(5~8). The honeycomb-like copper skeleton primarily provides macroscopic structural integrity and elastic resilience. It acts like a "scaffold," preventing irreversible plastic deformation of the electrodes under repeated expansion / contraction. The carbon layer 120 serves as a flexible buffer matrix. Carbon materials typically possess good flexibility and deformability. A coverage area 5 to 8 times that of the skeleton is key to its buffering effect. This means that microscopically, most areas are dominated by the soft, compressible / stretchable carbon layer 120. When silicon expands, the large-area carbon layer 120 absorbs most of the initial strain energy through its own elastic deformation (compression, bending). The carbon layer 120 uniformly transfers the dispersed stress to the robust copper skeleton network. The skeleton disperses concentrated stress throughout the network and stores and releases energy through the elastic deformation of its honeycomb structure.

[0077] It should be noted that the unfolded areas of the conductive framework 110 and the carbon layer 120 refer to the total area of ​​the three-dimensional object surface of the conductive framework 110 after being unfolded into a two-dimensional plane, and the total area of ​​the three-dimensional object surface of the carbon layer 120 after being unfolded into a two-dimensional plane, respectively. The ratio of the unfolded areas of the conductive framework 110 and the carbon layer 120 can be considered as the ratio of the proportion of copper metal units 111 to carbon layer 120.

[0078] Figure 3 This is another cross-sectional view of a negative electrode sheet provided in an embodiment of this application.

[0079] In some embodiments, reference Figure 3 The negative electrode also includes a plasma active layer 102, which is located between the silicon carbide active layer 101 and the elastic layer 11. The plasma active layer 102 firmly "rivets" the three-layer structure of the silicon carbide active layer 101, the plasma active layer 102, and the elastic layer 11 together, forming a robust whole with a gradient transition. Even if silicon undergoes significant volume changes, the interface will not delaminate, ensuring the long-term effectiveness of the buffering effect of the elastic layer 11. The plasma active layer 102 creates favorable conditions for the rapid and uniform shuttle of lithium ions between the silicon carbide active layer 101 and the elastic layer 11, helping to reduce the battery's internal resistance, improve rate performance, and promote the uniform insertion / extraction of lithium in silicon, reducing local stress concentration.

[0080] In some embodiments, the thickness of the plasma active layer 102 is 1 nm to 100 nm. The thickness range of the plasma active layer 102 can form a continuous, dense modified layer, effectively altering the surface chemical properties and providing an ideal substrate for constructing a stable SEI film, without significantly increasing impedance. The thickness of the plasma active layer 102 can be 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0081] The separator 3 is located between the positive electrode 1 and the negative electrode 2 to prevent short circuits caused by physical contact between the positive electrode 1 and the negative electrode 2. At the same time, it allows lithium ions to freely shuttle through the micropores while hindering electron transport, so that ions and electrons can form a circuit during the charging and discharging process of the battery. As a carrier of electrolyte, it adsorbs electrolyte to ensure ion transport efficiency. At high temperatures, it closes the pores to block ion flow and prevent thermal runaway.

[0082] The separator 3 can be any of the following: microporous membrane, modified microporous membrane, nonwoven membrane 3, and composite membrane 3. A microporous membrane is a separator 3 with pore sizes in the micrometer range, mainly including polyolefin microporous membranes and other polymer microporous membranes. A modified microporous membrane is a separator 3 obtained by modifying a microporous membrane; common modification methods include surface treatment, chemical grafting, and surface coating. A nonwoven membrane 3 has a small fiber diameter and typically exhibits higher porosity than other types of separators 3. A composite membrane 3 is prepared by coating or filling inorganic materials into a microporous membrane or nonwoven membrane 3, and exhibits higher thermal stability and electrolyte wettability compared to other types of separators 3.

[0083] In some embodiments, the separator 3 may be coated with polyvinylidene fluoride (PVDF) as an adhesive layer, giving the separator 3 excellent adhesion and flexibility. Due to the excellent adhesion of the separator 3, good contact performance is achieved between the separator 3 and the positive electrode 1 or between the separator 3 and the negative electrode 2, thereby reducing the assembly time of the energy storage cell and effectively reducing the overall production cost of the energy storage cell. Due to the excellent flexibility of the separator 3, its strength is improved, which helps to effectively enhance the impact resistance of the separator 3.

[0084] In some embodiments, the battery cell further includes a positive electrode tab and a negative electrode tab. The positive electrode tab / negative electrode tab is a metallic conductor that leads out the positive electrode plate 1 / negative electrode plate 2 of the energy storage cell from the cell. The positive electrode tab / negative electrode tab is the contact point between the positive electrode plate 1 / negative electrode plate 2 and an external contact component when the cell is charging and discharging. The external contact component can be a terminal post.

[0085] The electrolyte is the carrier of electrons between the positive and negative electrodes in a battery. In some embodiments, the electrolyte can be a liquid electrolyte, which consists of a solvent, a lithium salt, and additives. The solvent is used to dissolve the lithium salt and can include cyclic carbonates (PC, EC); chain carbonates (DEC, DMC, EMC); and carboxylic acid esters (MF, MA, EA, MA, MP, etc.). The lithium salt can be LiPF6, LiClO4, LiBF4, LiAsF6, etc. The additives can be one or more of the following: film-forming additives, conductive additives, flame-retardant additives, overcharge protection additives, additives for controlling the H2O and HF content in the electrolyte, additives for improving low-temperature performance, and multifunctional additives.

[0086] In some embodiments, the battery cell may further include a top cover, an adapter plate, and a terminal. The top cover engages with the housing. The adapter plate is located within the cavity and is electrically connected to the tab. The terminal passes through the top cover, and one end of the terminal is electrically connected to the adapter plate.

[0087] The adapter includes at least a first adapter and a second adapter, and the terminal includes a positive terminal and a negative terminal. The first adapter is electrically connected to the positive electrode tab and the positive terminal of the positive electrode 1, and the second adapter is electrically connected to the negative electrode tab and the negative terminal of the negative electrode 2.

[0088] The negative electrode sheet provided in this application embodiment includes a silicon-carbon active layer 101 composed of silicon-carbon composite material. The silicon-carbon active layer 101, as a silicon-carbon negative electrode, has advantages such as good stability, small volume change and excellent conductivity, thereby improving the expansion and failure problems of silicon-based negative electrode materials.

[0089] The elastic layer 11 is located on the silicon carbide active layer 101 and consists of a conductive framework 110 (a honeycomb structure of copper metal units 111) and a carbon layer 120. Its buffering effect is mainly based on the following mechanisms: First, the conductive framework 110 is constructed from multiple hexagonal copper metal units 111 in a honeycomb structure. The honeycomb structure has high specific strength, high toughness, and good energy absorption characteristics. When the silicon carbide active layer 101 undergoes volume changes during lithium-ion insertion / extraction, the honeycomb structure can absorb and disperse stress through elastic deformation, buffering mechanical impacts like a spring. Specifically, the isotropic nature of the honeycomb structure allows it to uniformly withstand multi-directional stresses, reducing stress concentration points and effectively suppressing silicon particle breakage and electrode layer peeling. Copper itself has good ductility and conductivity, ensuring that the elastic layer 11 will not break during buffering while maintaining the continuity of the electron conduction path. Second, the carbon layer 120 enhances interface stability and adaptability: the carbon layer 120 is wrapped within the conductive framework 110. Carbon materials typically have good flexibility and lubricity, further adapting to the volume changes of silicon. The carbon layer 120 can fill the gaps in the honeycomb structure, forming a more continuous buffer layer and reducing the direct contact pressure between the silicon carbide active layer 101 and the separator. The carbon layer 120 also helps stabilize the formation of the SEI film because carbon materials have good compatibility with the electrolyte, which can reduce side reactions and thus alleviate interfacial instability caused by volume changes.

[0090] The elastic layer 11, combined with the silicon carbide active layer 101, forms a "stress buffer." During lithium-ion insertion / extraction, the expansion of silicon is first absorbed by the elastic layer 11, preventing stress from being directly transmitted to the current collector and separator. During contraction, the elastic restoring force of the elastic layer 11 maintains the tightness of the electrode structure, preventing the electrode from loosening. This design is similar to adding a flexible layer between a rigid material (silicon) and a rigid component (such as the negative electrode current collector 100), thereby improving the electrode's resilience. By buffering stress and deformation, the elastic layer 11 reduces the mechanical degradation of the silicon carbide active layer 101, delaying capacity decay and allowing the battery cell to withstand more charge-discharge cycles. The elastic layer 11 prevents damage to the electrode structure and reduces the risk of internal short circuits. The conductive framework 110 ensures good electronic conduction, avoiding the impedance increase caused by the buffer layer, enabling the battery to maintain stable performance even at high rates.

[0091] During prolonged charging, the elastic layer 11 of this battery cell absorbs the expansion force of silicon, preventing excessive compression of the separator and greatly reducing the risk of separator deformation or damage due to stress accumulation. Secondly, by stabilizing the SEI film, interfacial side reactions and lithium consumption are reduced, ensuring long-term capacity retention and efficient operation. Furthermore, this fundamentally solves the short lifespan limitation of silicon anodes, allowing the battery to stably undergo complete and drastic volume expansion and contraction during long-term charge and discharge processes. It can withstand deep cycling for several years, once a day, significantly improving the battery's cycle life and meeting the stringent requirements for cycle count in long-term energy storage.

[0092] Accordingly, according to some embodiments of this application, another aspect of this application provides a method for preparing a battery cell, which is used to prepare the battery cell provided in the above embodiments. The same or corresponding technical features as those in the above embodiments will not be described in detail here.

[0093] refer to Figure 1 and Figure 2 The preparation method includes: forming a negative electrode sheet, the negative electrode sheet including: a negative electrode current collector 100 and a silicon carbide active layer 101; an elastic layer 11, the elastic layer 11 is located on the silicon carbide active layer 101, the elastic layer 11 includes a conductive framework 110 and a carbon layer 120, the conductive framework 110 is located in the carbon layer 120, and the conductive framework 110 is constructed by multiple hexagonal copper metal units 111 in a honeycomb structure.

[0094] In some embodiments, the process steps for forming the negative electrode sheet include: providing a negative electrode current collector 100.

[0095] A silicon-carbon active layer 101 is formed on the surface of the negative electrode current collector 100. The silicon-carbon active layer 101 is formed using chemical vapor deposition (CVD). By precisely controlling the gas reaction, nano-silicon (or silicon oxide) can be deposited in situ on a porous carbon matrix or graphite surface, forming a silicon-carbon composite structure. The rich microporous structure of the porous carbon matrix enables the in-situ confined growth of silicon particles. Simultaneously, thanks to the excellent conductivity and mechanical strength of carbon materials, the CVD silicon-carbon composite material exhibits excellent specific capacity and cycle stability as a negative electrode. Specific steps include: First, the negative electrode current collector 100 is placed in the CVD reaction chamber, and a silicon source gas (such as silane, SiH4) is introduced. Under specific temperature (400℃~600℃) and pressure, the silane decomposes and deposits nanoscale silicon particles or a silicon film on the current collector surface. Subsequently, without disrupting the vacuum, the gas source is switched to a carbon source gas (such as methane CH4, ethylene C2H4, or benzene C6H6, etc.). Carbon atoms produced by the decomposition of the carbon source gas are deposited on the surface of the previously formed silicon particles, forming a uniform carbon coating layer. Finally, silicon source gas and carbon source gas are simultaneously introduced into the reaction chamber in a certain ratio. By controlling the temperature, pressure, and gas ratio, silicon and carbon are co-deposited to directly form a silicon-carbon composite, namely the silicon-carbon active layer 101.

[0096] In some embodiments, the preparation method includes: removing residual contaminants on the surface of the silicon carbide active layer 101 by ultrasonic cleaning to ensure that the surface of the silicon carbide active layer 101 is clean.

[0097] Continue to refer to Figure 2 An initial elastic membrane is formed, which contains an initial conductive framework composed of copper atoms and carbon atoms. The carbon atoms are located within the initial conductive framework and encapsulate the silicon particles within the silicon carbon active layer 101. The initial elastic membrane is then subjected to a control process to enable the copper atoms in the initial conductive framework to self-assemble into hexagonal copper metal units 111 and construct a honeycomb structure. The carbon atoms are then used to construct a carbon layer 120.

[0098] In some embodiments, the process steps of dynamically co-sputtering a silicon-carbon anode sheet to form an initial elastic film include: sputtering a silicon-carbon active layer 101 with a copper target to form copper atoms, the copper atoms forming an initial conductive framework; sputtering a silicon-carbon active layer 101 with a carbon target to form carbon atoms, the carbon atoms being located within the initial conductive framework, and the carbon atoms encapsulating the silicon particles within the silicon-carbon active layer 101.

[0099] In some embodiments, the process steps for conditioning the initial elastic membrane include: rotating the initial elastic membrane at a uniform speed of 5 rpm to 20 rpm, and using centrifugal force and plasma irradiation to drive the periodic nucleation of copper atoms, so that the copper atoms self-assemble into hexagonal copper metal units 111, and construct a honeycomb structure. During the periodic nucleation of copper atoms driven by plasma irradiation, the periodic temperature gradient (80°C to 100°C at the center → 50°C to 70°C at the edge) is formed by utilizing centrifugal force and plasma irradiation inhomogeneity, driving the periodic nucleation of copper atoms and self-assembling them into honeycomb pore walls.

[0100] In some embodiments, the sputtering power of sputtering copper atoms onto the silicon-carbon active layer 101 using a copper target is a first power; the sputtering power of sputtering carbon atoms onto the silicon-carbon active layer 101 using a carbon target is a second power, and the ratio of the second power to the first power is 1.3 to 20.

[0101] The ratio of the second power to the first power can be 1.3~5, 5~13, 13~15, 15~17, or 17~20. The ratio of the second power to the first power can be 1.3, 2.1, 3, 4.2, 5.6, 7.1, 8.6, 9.3, 10, 11, 13.2, 15, 16.8, 18, 19.1, or 20.

[0102] In some embodiments, the first power is 100W~180W; the second power is 270W~350W. The first power can be 100W, 110W, 120W, 130W, 140W, 150W, 160W, 170W, or 180W. The second power can be 270W, 280W, 290W, 300W, 310W, 320W, 330W, 340W, or 350W.

[0103] Copper atoms are formed by sputtering a silicon-carbon active layer 101 using a copper target. The specific mechanism by which copper atoms form the initial conductive framework is as follows: During the sputtering process, argon ions are accelerated by an electric field and bombard the copper target, sputtering copper atoms from the target surface. These copper atoms have high kinetic energy (typically a few electron volts to tens of electron volts) and fly towards the substrate surface in gaseous form. After reaching the substrate surface, the copper atoms can diffuse rapidly due to their high surface mobility. Copper atoms move from high-energy sites (such as defects, step edges) to low-energy sites, seeking stable adsorption sites. The tangential force generated by the rotation of the silicon-carbon active layer 101 (such as centrifugal force or surface stress gradient) guides the copper atoms to migrate preferentially along the tangential direction of rotation, which helps the atoms rearrange on the surface. Finally, the high-mobility copper atoms preferentially migrate along the tangential direction of the silicon-carbon active layer 101's substrate rotation, forming a hexagonal framework prototype, i.e., the initial conductive framework.

[0104] The hexagonal framework is chosen because the hexagonal structure is one of the most energy-stable arrangements, similar to the closest-packed facets of hexagonal close-packed (HCP) or face-centered cubic (FCC) crystals. Copper has an FCC structure, and its (111) crystal face naturally exhibits hexagonal symmetry. During deposition, high-mobility copper atoms self-organize through surface diffusion to form a hexagonal grid. The hexagonal units connect to each other under tangential forces, forming a honeycomb-like framework. This structure is similar to the self-assembly phenomenon of Bénard convection cells or nanoporous films.

[0105] In some embodiments, copper atoms are sputtered onto the silicon carbide active layer 101 using a copper target. The process parameters for forming the initial conductive framework of copper atoms include: under the action of a DC power supply (first power 100W~180W), copper atoms are sputtered onto the substrate surface under argon ion bombardment at a temperature of 200°C~400°C and a pressure of 0.1Pa~1Pa.

[0106] Carbon atoms are formed by sputtering a carbon-silicon active layer 101 using a carbon target. The carbon atoms are located within the initial conductive framework. The specific mechanism by which carbon atoms coat the silicon particles within the carbon-silicon active layer 101 is as follows: carbon atoms are deposited from the gas phase. Due to their weak migration ability, they do not skip pores or trenches, but are directly deposited on any surface they can access, including the sides and bottom of the copper framework, as well as the surface of the silicon particles.

[0107] This deposition pattern is a top-down filling method. Carbon atoms accumulate simultaneously from the top, sidewalls, and bottom of the pores, like "filling sand," eventually filling all the voids evenly to form a dense structure. This ensures that there are no voids between the copper framework and the silicon carbide active layer 101, achieving excellent mechanical coupling and electrical contact.

[0108] The specific mechanism for modulating the initial elastic film is as follows: In plasma (such as magnetron sputtered plasma), the energy distribution is usually non-uniform. The central region of the initial elastic film directly faces the region with the highest plasma density and receives the strongest irradiation, thus having the highest temperature (80℃~100℃). The edge region receives weaker irradiation and has a lower temperature (50℃~70℃). When the substrate rotates at a uniform speed of 5rpm~20rpm, any point on the initial elastic film will periodically alternate between the high-temperature region (near the center) and the low-temperature region (near the edge). For an initial elastic film rotating at 10rpm, a point on it will experience a complete hot-cold cycle every 6 seconds. When a point rotates to the central high-temperature region, the temperature at that point rises, and the copper atoms adsorbed there gain extremely high mobility, becoming very "active." When the point rotates to the edge low-temperature region, the temperature drops, and the mobility of the copper atoms decreases sharply, becoming "sluggish" or even "frozen." In the high-temperature region, atoms rapidly converge towards potential nucleation sites (such as defects or existing islands), causing these sites to grow. When this growing nucleus is rotated with the substrate to the low-temperature region, atomic mobility drops sharply. Atomic diffusion almost ceases, and the current structure is "frozen" and fixed, preventing excessive disordered growth or disintegration. Through repeated thermal cycles, this controlled, rhythmic growth pattern ensures that nucleation and growth preferentially occur on the lowest-energy path defined by both the temperature and centrifugal forces. The hexagonal honeycomb structure represents the most energy-stable arrangement under these periodic boundary conditions because it most effectively releases stress and minimizes surface energy.

[0109] By adjusting the ratio of substrate rotation speed to sputtering power, and utilizing the difference between the high mobility of copper and the low diffusivity of carbon, spontaneous competitive growth of the material is induced under a dynamic temperature gradient, ultimately forming a biomimetic honeycomb structure. Copper atoms preferentially assemble along the rotation direction into a continuous hexagonal conductive framework 110, while carbon atoms fill the pores between the honeycomb structures and can coat silicon particles (due to the small amount of exposed silicon particles on the electrode surface after rolling, these areas become preferential deposition sites for carbon atoms after plasma activation, and are further covered by the deposited and diffused carbon layer 120). Simultaneously, a conductive network and an elastic buffer layer are constructed (carbon, compared to silicon, has functions such as mechanical buffering, enhanced conductivity, and interface stabilization). After sputtering, low-temperature annealing is used to eliminate internal stress and optimize the copper-carbon interface bonding strength. If necessary, atomic layer deposition technology can be further employed to uniformly cover the surface with an ultrathin oxide layer to seal micropores and suppress side reactions.

[0110] In some embodiments, reference Figure 3 The process includes, after forming the silicon carbide active layer 101 and before forming the initial elastic film, performing a plasma activation treatment on the silicon carbide active layer 101 to form an uneven structure on the surface of the silicon carbide active layer 101.

[0111] Specifically, the silicon carbide active layer 101 is subjected to plasma activation treatment, in which high-energy particles are used to bombard the surface in an argon-oxygen mixed gas to form a nanoscale rough structure and introduce active groups such as hydroxyl and carboxyl groups to enhance the adhesion of subsequent coatings.

[0112] In some embodiments, after plasma activation treatment of the silicon carbide active layer 101, the process includes: evacuating to a pressure ≤ 5 × 10⁻⁶. -4 Pa; Argon gas is introduced to 0.3 Pa~0.8 Pa, and pre-sputtered through copper and carbon targets for 2 min~5 min to remove oxides on the target surface. In this way, the activity of active groups such as hydroxyl and carboxyl groups on the surface of silicon carbide active layer 101 can be improved, and some oxidation by-products can be removed.

[0113] The preparation method includes: providing a positive electrode sheet and a separator; stacking a negative electrode sheet, a separator and a positive electrode sheet in sequence; stacking a negative electrode sheet, a separator and a positive electrode sheet in sequence; obtaining a cell assembly by winding or stacking; placing the cell assembly into a battery case; injecting electrolyte into the battery case; and then encapsulating it to obtain a single battery cell.

[0114] The innovation of this application lies in the dynamic co-sputtering deposition technology used in the preparation method. This technology can achieve complex microstructure control in a single process. While traditional methods such as carbon coating or nanostructuring can alleviate the volume expansion problem of silicon-based materials to some extent, they often require multiple complex processes and cannot simultaneously meet the multiple requirements of mechanical support, ion transport, and electronic conductivity. In contrast, this application's embodiment, by adjusting the ratio of substrate rotation speed to sputtering power, utilizes the difference between the high mobility of copper atoms and the low diffusivity of carbon atoms to induce spontaneous competitive growth of materials under a dynamic temperature gradient, forming a biomimetic honeycomb structure with excellent mechanical and electrochemical properties. This cross-scale collaborative design is not available in existing technologies.

[0115] This application utilizes magnetron sputtering technology to construct a biomimetic honeycomb structure on the surface of a silicon-carbon anode, mimicking the mechanical and mass transport characteristics of a honeycomb in nature. Through a competitive growth mechanism using copper and carbon dual targets, the integrated construction of the hexagonal conductive framework 110 and the elastic buffer layer is achieved in a single-step low-temperature process. This unique structure not only effectively disperses the volume expansion stress generated during the charging and discharging of silicon materials, reducing the risk of electrode pulverization, but also optimizes the transport paths of ions and electrons, thereby significantly improving the battery's energy density, cycle life, and fast-charging performance.

[0116] According to some embodiments of this application, another aspect of this application provides a battery device, including: a battery cell prepared by the method of preparing a battery cell as described in any of the above embodiments, or a battery cell as described in the above embodiments, the battery device including one or more of a battery module, a battery pack, and an energy storage battery.

[0117] According to some embodiments of this application, another aspect of this application provides an electrical device, including a battery device as described in the above embodiments, the battery device being used to provide electrical energy.

[0118] Electrical devices include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0119] According to some embodiments of this application, another aspect of this application provides an energy storage device, including a battery device as described in the above embodiments, the battery device being used to store electrical energy.

[0120] Energy storage devices include, but are not limited to, residential energy storage cabinets, commercial energy storage cabinets, energy storage containers, energy storage racks, energy storage power stations, energy storage battery packs, or portable energy storage systems. Energy storage devices may also include energy management systems (EMS), battery management systems (BMS), and power conversion systems (PCS).

[0121] The beneficial effects of the embodiments of this application will be further illustrated below with reference to the examples.

[0122] Example 1:

[0123] (1) Preparation of negative electrode: First, the residual contaminants on the surface of the silicon-carbon active layer are removed by ultrasonic cleaning to ensure that the surface of the silicon-carbon active layer is clean; then, the silicon-carbon negative electrode is dynamically co-sputtered: 1. Copper target activation: the DC power supply (120W) is turned on, and copper atoms are sputtered to the surface of the substrate under the bombardment of argon ions. Due to their high mobility, they preferentially migrate along the rotational tangential direction of the substrate to form a hexagonal skeleton prototype; 2. Simultaneous sputtering of carbon target: the RF power supply (300W) is turned on, and carbon atoms are deposited in the gaps of the copper skeleton with low mobility, filling the pores and coating the silicon particles; 3. Rotation control: the substrate is rotated at a uniform speed of 10rpm. Using centrifugal force and plasma irradiation inhomogeneity, a periodic temperature gradient is formed, which drives the periodic nucleation of copper atoms and self-assembles them into honeycomb pore walls.

[0124] (2) Assemble battery cells.

[0125] Example 2: The steps are basically the same as those in Example 1, except that: after the step of removing residual contaminants on the surface of the silicon carbide active layer, before the step of dynamic co-sputtering deposition on the silicon carbide anode sheet, the following steps are included: plasma activation treatment, in which high-energy particles are used to bombard the surface in an argon-oxygen mixed gas to form a nanoscale rough structure and introduce active groups such as hydroxyl and carboxyl groups to enhance the adhesion of subsequent coatings.

[0126] Then, the process proceeds to the sputtering chamber for preparation and pre-sputter cleaning: the plasma-activated silicon-carbon anode sheet is loaded into the sputtering chamber, and the chamber pressure is evacuated to <5×10⁻⁶. -4 Pa; Argon gas is introduced to 0.3 Pa~0.8 Pa, and pre-sputtered through copper and carbon targets for 3 min to remove oxides from the target surface.

[0127] Comparative Example 1: The steps are basically the same as those in Example 1, except that there is no dynamic co-sputtering deposition step on the silicon-carbon anode sheet, that is, the anode sheet is a silicon-carbon anode sheet, and the surface of the silicon-carbon anode sheet has no elastic layer.

[0128] Contact angle and electrochemical performance tests were performed on the examples and comparative examples in sequence, and the results were summarized and recorded in Table 1.

[0129] Table 1

[0130]

[0131] Experimental results show that this biomimetic honeycomb structure can not only effectively inhibit electrode pulverization failure, but also enhance electrolyte wettability and further improve the stability of the electrode / electrolyte interface.

[0132] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A battery cell, characterized in that, include: A battery casing having a cavity inside, and an electrolyte being contained within the cavity; A battery cell assembly, wherein the battery cell assembly is located within the cavity and the battery cell assembly is located within the electrolyte; The battery cell assembly includes a positive electrode, a separator, and a negative electrode, wherein the negative electrode includes: Negative electrode current collector and silicon carbide active layer; An elastic layer is located on the silicon carbide active layer. The elastic layer includes a conductive framework and a carbon layer. The conductive framework is located within the carbon layer. Multiple copper atoms self-assemble into hexagonal copper metal units. The conductive framework is constructed from multiple hexagonal copper metal units in a honeycomb structure. The side length of the copper metal units ranges from 50 μm to 80 μm.

2. The battery cell according to claim 1, characterized in that, The elastic layer includes 2 to 3 layers of the conductive framework; the thickness of the conductive framework ranges from 100 nm to 200 nm.

3. The battery cell according to claim 1 or 2, characterized in that, The ratio of the unfolded area of ​​the conductive framework to that of the carbon layer is 1:(5~8).

4. The battery cell according to claim 1, characterized in that, Also includes: A plasma active layer is located between the silicon carbide active layer and the elastic layer.

5. The battery cell according to claim 4, characterized in that, The thickness of the plasma active layer is 1 nm to 100 nm.

6. A method for preparing a single battery cell, characterized in that, include: A negative electrode sheet is formed, the negative electrode sheet comprising: a negative electrode current collector and a silicon carbide active layer; An elastic layer is located on the silicon carbide active layer. The elastic layer includes a conductive framework and a carbon layer. The conductive framework is located within the carbon layer. Multiple copper atoms self-assemble into hexagonal copper metal units. The conductive framework is constructed from multiple hexagonal copper metal units in a honeycomb structure. The side length of the copper metal units ranges from 50 μm to 80 μm. A positive electrode and a separator are provided; the negative electrode, separator and positive electrode are stacked in sequence, and the negative electrode, separator and positive electrode are stacked in sequence. The cell assembly is obtained by winding or stacking. The cell assembly is placed into a battery case, electrolyte is injected into the battery case and then it is packaged to obtain a single battery cell.

7. The method for preparing a single battery cell according to claim 6, characterized in that, The process steps for forming the negative electrode sheet include: Provide negative electrode current collector; A silicon carbide active layer is formed, wherein the silicon carbide active layer is located on the surface of the negative electrode current collector; The silicon carbide active layer is subjected to plasma activation treatment to form an uneven structure on the surface of the silicon carbide active layer. An initial elastic membrane is formed, wherein the initial elastic membrane has an initial conductive framework composed of copper atoms and carbon atoms, wherein the carbon atoms are located within the initial conductive framework and the carbon atoms encapsulate the silicon particles within the carbon silicon active layer. The initial elastic membrane is subjected to a conditioning process to cause the copper atoms in the initial conductive framework to self-assemble into hexagonal copper metal units and construct a honeycomb structure; the carbon atoms are constructed into the carbon layer.

8. The method for preparing a battery cell according to claim 7, characterized in that, The process steps for forming the initial elastic film include: sputtering copper atoms onto the silicon-carbon active layer using a copper target to form copper atoms, which form an initial conductive framework; and sputtering carbon atoms onto the silicon-carbon active layer using a carbon target to form carbon atoms, which are located within the initial conductive framework and coat the silicon particles within the silicon-carbon active layer.

9. The method for preparing a battery cell according to claim 8, characterized in that, The process steps for regulating the initial elastic membrane include: rotating the initial elastic membrane at a constant speed of 5 rpm to 20 rpm, using centrifugal force and plasma irradiation to drive the periodic nucleation of copper atoms, so that the copper atoms self-assemble into hexagonal copper metal units and construct a honeycomb structure.

10. The method for preparing a single battery cell according to claim 8, characterized in that, The sputtering power used to sputter the silicon-carbon active layer with a copper target to form copper atoms is the first power; the sputtering power used to sputter the silicon-carbon active layer with a carbon target to form carbon atoms is the second power, and the ratio of the second power to the first power is 1.3 to 20.

11. The method for preparing a battery cell according to claim 10, characterized in that, The first power is 100W~180W; the second power is 270W~350W.

12. The method for preparing a battery cell according to claim 7, characterized in that, After plasma activation treatment of the silicon carbide active layer, the process includes: evacuating to a pressure ≤ 5 × 10⁻⁶. -4 Pa; introduce argon gas to 0.3 Pa~0.8 Pa, and pre-sputter through copper and carbon targets for 2 min~5 min.

13. A battery device, characterized in that, The battery device includes a battery cell prepared by the method of preparing a battery cell as described in any one of claims 1 to 5 or as described in any one of claims 6 to 12, and the battery device includes one or more of a battery module, a battery pack, and an energy storage battery.

14. An electrical appliance, characterized in that, The electrical device includes the battery device as described in claim 13, the battery device being used to provide electrical energy.

15. An energy storage device, characterized in that, The energy storage device includes the battery device as described in claim 13, the battery device being used to store electrical energy.

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