Battery monomer, negative electrode material, preparation method of negative electrode active material and electric device

Abstract

The invention provides a battery monomer, a negative electrode material, a preparation method of the negative electrode material and a power utilization device. The battery monomer comprises a negative electrode piece, the negative electrode piece comprises a negative electrode current collector and a negative electrode active layer located on at least one side of the negative electrode current collector, the negative electrode active layer comprises a negative electrode material, the negative electrode material comprises a negative electrode active material, and the negative electrode active material comprises a carbon material and silicon particles. The carbon material is of a hollow shell structure, the shell structure is provided with pore channels, and the silicon particles are located on the surface of the shell structure and / or in the pore channels. The battery monomer disclosed by the invention has high energy density, and the dynamic performance and the cycling stability are improved at the same time.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method for preparing a battery cell, a negative electrode material, a negative electrode active material, and an electrical device. Background Technology

[0002] In recent years, with the increasingly wide range of applications, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. Due to the significant advancements in battery technology, higher requirements have been placed on their energy density, cycle performance, and kinetic performance. Summary of the Invention

[0003] This application was made in view of the above-mentioned problems, and its purpose is to provide a battery cell, a negative electrode material, a method for preparing the negative electrode material, and an electrical device. The battery cell of this application has high energy density while improving the kinetic performance and cycle stability of the battery cell.

[0004] To achieve the above objectives, the first aspect of this application provides a battery cell including a negative electrode sheet, the negative electrode sheet including a negative electrode material, the negative electrode material including a negative electrode active material, the negative electrode active material including a carbon material and silicon particles, the carbon material having an internally hollow shell structure, the shell structure having channels, and the silicon particles located on the surface of the shell structure and / or within the channels.

[0005] Therefore, this application utilizes a carbon material with an internal hollow shell structure and silicon particles located on the surface and / or within the shell pores of the carbon material to form a negative electrode active material. This not only increases the energy density of the battery cell but also reduces the DCR of the battery cell, shortens the charging time, and improves the kinetic performance of the battery cell. Furthermore, the internal hollow structure provides space for the volume expansion of the silicon particles, reducing the volume change of the negative electrode sheet, thereby improving the cycle stability of the battery cell.

[0006] In any embodiment, the BET specific surface area of ​​the negative electrode material is 0.2-30 m². 2 / g or 0.5-3m 2 / g. Therefore, on the one hand, it provides more channels for lithium-ion transport, improving the kinetic performance of the battery cell; on the other hand, it increases the energy density of the battery cell while suppressing side reactions on the negative electrode, thus improving the cycle stability of the battery cell.

[0007] In any embodiment, the average outer diameter of the negative electrode active material is 2-20 μm or 3-13 μm. This reduces the DCR of the battery cell, improving its kinetic performance, and also mitigates the negative impact of excessively small outer diameter on the battery cell's energy density and cycle stability.

[0008] In any embodiment, the average thickness of the shell structure is 0.5-8 μm or 1-7 μm.

[0009] Therefore, while ensuring the energy density of the battery cells, the lithium-ion transport path is shortened, improving the dynamic performance of the battery cells. On the other hand, space is reserved for the volume expansion of silicon, improving the cycle stability of the battery cells.

[0010] In any embodiment, the negative electrode active material is spherical; and / or, the sphericity of the negative electrode active material is 0.5-1 or 0.7-1. This reduces the crushing degree of the negative electrode active material particles and enhances their strength.

[0011] In any embodiment, the silicon particles have a particle size of 0.5-8 nm.

[0012] Therefore, while ensuring the energy density of the battery cell, the expansion of silicon particle volume is suppressed, thereby improving the cycle stability of the battery cell.

[0013] In any embodiment, the carbon material has an average pore size of 0.8-5 nm.

[0014] In any embodiment, the pore volume of the carbon material is 0.6-1.06 cm³. 3 / g.

[0015] In any embodiment, the BET specific surface area of ​​the carbon material is 1000-2000 m². 2 / g.

[0016] Therefore, the average pore size, pore volume and / or specific surface area of ​​the carbon material are within the above range, which provides a larger space for silicon particles, improves the energy density of the battery cell, and at the same time reserves enough space for the expansion of silicon particles, suppresses the side reactions of the negative electrode, and improves the cycle stability of the battery cell.

[0017] In any embodiment, the areal density of the negative active layer is 5-9 mg / cm³. 2 .

[0018] In any embodiment, the mass ratio of the carbon material to the silicon particles is 3:7-8:2. This is beneficial for increasing the energy density of the battery cell, while suppressing the expansion of the negative electrode caused by the silicon particles and improving the cycle stability of the battery cell.

[0019] In any embodiment, the negative electrode active material includes a core and a coating layer covering the core, wherein the carbon material and the silicon particles are disposed in the core, and the coating layer includes carbon; and / or,

[0020] The average thickness of the coating layer is 1-2 nm.

[0021] Therefore, the carbon coating layer helps to improve the conductivity of the negative electrode material.

[0022] A second aspect of this application also provides a negative electrode material, including a negative electrode active material, the negative electrode active material comprising a carbon material and silicon particles, the carbon material having an internally hollow shell structure, the shell structure having channels, and the silicon particles being located on the surface of the shell structure and / or within the channels.

[0023] Therefore, this application utilizes a carbon material with an internal hollow shell structure and silicon particles located on the surface and / or within the shell pores of the carbon material to form a negative electrode active material. This not only increases the energy density of the battery cell but also reduces the DCR of the battery cell, shortens the charging time, and improves the kinetic performance of the battery cell. Furthermore, the internal hollow structure provides space for the volume expansion of the silicon particles, reducing the volume change of the negative electrode sheet, thereby improving the cycle stability of the battery cell.

[0024] In any embodiment, the BET specific surface area of ​​the negative electrode material is 0.2-30 m². 2 / g or 0.5-3m 2 / g.

[0025] In any embodiment, the average outer diameter of the negative electrode active material is 2-20 μm or 3-13 μm.

[0026] In any embodiment, the average thickness of the shell structure is 0.5-8 μm or 1-7 μm.

[0027] In any embodiment, the negative electrode active material is spherical; and / or, the sphericity of the negative electrode active material is 0.5-1 or 0.7-1.

[0028] In any embodiment, the silicon particles have a particle size of 0.5-8 nm.

[0029] In any embodiment, the carbon material has an average pore size of 0.8-5 nm.

[0030] In any embodiment, the pore volume of the carbon material is 0.6-1.06 cm³. 3 / g.

[0031] In any embodiment, the BET specific surface area of ​​the carbon material is 1000-2000 m². 2 / g.

[0032] In any embodiment, the mass ratio of the carbon material to the silicon particles is 3:7-8:2.

[0033] In any embodiment, the negative electrode active material includes a core and a coating layer covering the core, wherein the carbon material and the silicon particles are disposed in the core, and the coating layer includes carbon; and / or,

[0034] The average thickness of the coating layer is 1-2 nm.

[0035] A third aspect of this application provides a method for preparing a negative electrode material, comprising the following steps:

[0036] A first mixture is obtained by mixing a resin containing a cyclic structure, a curing agent, a water-in-oil emulsifier, and an oil-phase solvent.

[0037] An aqueous solvent is added to the first mixture and mixed to obtain a water-in-oil emulsion;

[0038] A second mixture is obtained by mixing a hydrophilic surfactant, an oil-in-water emulsifier, a curing agent, and an aqueous solvent.

[0039] The water-in-oil emulsion is added to the second mixture and mixed to obtain an oil-in-water-in-oil emulsion;

[0040] The oil-in-water-in-oil emulsion is subjected to a solidification reaction, followed by solid-liquid separation, and the solid phase is collected.

[0041] The solid material is dried, calcined, and pore-formed to obtain a carbon material.

[0042] Using the carbon material as a substrate, a negative electrode material is obtained by vapor deposition using a silicon source;

[0043] The negative electrode material includes a negative electrode active material, which includes carbon material and silicon particles. The carbon material has a hollow shell structure with channels. The silicon particles are located on the surface of the shell structure and / or within the channels.

[0044] In any embodiment, in the step of preparing the water-in-oil emulsion, a pre-reaction is performed after mixing to obtain the water-in-oil emulsion.

[0045] In any embodiment, during the step of preparing the water-in-oil emulsion, the pre-reaction temperature is 70°C-120°C; and / or,

[0046] The pre-reaction time is 0-60 min.

[0047] In any embodiment, in the step of preparing the carbon material, the calcination temperature is 900℃-980℃; and / or,

[0048] The roasting time is 4-8 hours.

[0049] In any embodiment, in the step of preparing the carbon material, the pore-forming process is water vapor pore-forming.

[0050] In any embodiment, in the step of preparing the solid, the curing temperature is the curing temperature of the resin containing the cyclic structure.

[0051] The curing reaction takes 3-12 hours.

[0052] In any embodiment, in the step of preparing the first mixture, the mass ratio of the cyclic resin to the oil phase solvent is 10:4-10:0.5.

[0053] In any embodiment, in the step of preparing the water-in-oil emulsion, the mass ratio of the aqueous solvent to the first mixture is 1:16.28-7:16.28.

[0054] In any embodiment, in the step of preparing the oil-in-water-in-oil emulsion, the mass ratio of the oil-in-water emulsion to the second mixture is 10:122-30:122.

[0055] In any embodiment, during the step of preparing the negative electrode active material, the silicon source flow rate of the vapor deposition is 0.5-5 L / min.

[0056] In any embodiment, during the step of preparing the negative electrode active material, the temperature of the vapor deposition is 550-600°C; and / or,

[0057] The vapor deposition time is 3-12 hours.

[0058] In any embodiment, the method further includes: after vapor deposition, coating the surface of the vapor deposition product with carbon to obtain a negative electrode active material containing a carbon coating layer.

[0059] In any embodiment, the curing agent is the curing agent corresponding to the resin containing the cyclic structure.

[0060] In any embodiment, the water-in-oil emulsifier includes one or more of Span-80, polyglycerol ester, and diglyceride.

[0061] In any embodiment, the hydrophilic surfactant includes one or more of sodium dodecyl sulfate and polyglycerol-10 octyl decanoate.

[0062] In any embodiment, the oil-in-water emulsifier includes one or more of OP-10 and polysorbate.

[0063] In any embodiment, the negative electrode active material prepared by the method is the negative electrode material in the first or second aspect of this application.

[0064] The fourth aspect of this application provides a battery device, including a battery cell according to the first aspect of this application, a negative electrode material according to the second aspect of this application, or a negative electrode material prepared by the method according to the third aspect of this application.

[0065] The fifth aspect of this application provides an electrical device, including a battery cell of the first aspect of this application or a battery device of the fourth aspect of this application. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of a battery cell according to one embodiment of this application.

[0067] Figure 2 yes Figure 1 An exploded view of a battery cell according to one embodiment of this application is shown.

[0068] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application.

[0069] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0070] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0071] Figure 6 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to one embodiment of this application.

[0072] Figure 7A This is a SEM image of the negative electrode active material in Example 1 of this application.

[0073] Figure 7B This is a magnified SEM image of the negative electrode active material particles in Example 1 of this application.

[0074] Explanation of reference numerals in the attached figures:

[0075] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Implementation

[0076] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery module, battery pack, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0077] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0078] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0079] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0080] [Battery cell]

[0081] 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.

[0082] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion 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.

[0083] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. 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, prevents short circuits while allowing active ions to pass through.

[0084] One embodiment of this application provides a battery cell including a negative electrode sheet, the negative electrode sheet including a negative electrode material, the negative electrode material including a negative electrode active material, the negative electrode active material including a carbon material and silicon particles, the carbon material having an internally hollow shell structure, the shell structure having channels, and the silicon particles located on the surface of the shell structure and / or within the channels.

[0085] While porous carbon vapor-deposited silicon (CVD) composites can improve the energy density of individual battery cells when used as negative electrode active materials, the long lithium-ion transport path within these composites results in high impedance, leading to a higher DCR (discharge rate) and decreased kinetic performance. Furthermore, silicon expansion during charge and discharge causes volume changes in the negative electrode, worsening the cycle stability of the battery. Even reducing the particle size of the porous CVD composite to shorten the lithium-ion transport path increases surface reactivity and side-reaction gas production in the negative electrode, deteriorating the cycle and storage performance of the battery. Additionally, small-particle-size composites are prone to uneven deposition and channel blockage during fabrication, and the use of more binders in negative electrode fabrication further deteriorates the battery's kinetic performance.

[0086] Although the mechanism is not yet clear, the applicant unexpectedly discovered that filling the surface and / or shell pores of the carbon material with silicon particles improves the energy density of the battery cell. Simultaneously, designing the carbon material with a hollow shell structure eliminates the transport of lithium ions within the carbon material, allowing lithium ions to be transported directly through the shell, shortening the lithium ion transport path, reducing the DCR of the battery cell, shortening the charging time of the battery cell, and improving the kinetic performance of the battery cell. Furthermore, the hollow interior provides space for the volume expansion of the silicon particles, reducing the volume change of the negative electrode and improving the cycle stability of the battery cell.

[0087] In some embodiments, the BET specific surface area of ​​the negative electrode material is 0.2-30 m². 2 / g or 0.5-3m 2 / g, for example 0.2m 2 / g, 0.5m 2 / g, 0.8m 2 / g, 0.9m 2 / g, 1m 2 / g, 1.2m 2 / g, 1.4m 2 / g, 1.6m 2 / g, 1.9m 2 / g、2m 2 / g, 2.5m 2 / g、3m 2 / g、4m 2 / g、5m 2 / g、6m 2 / g、7m 2 / g、8m 2 / g、9m 2 / g, 10m 2 / g、14m 2 / g, 16m 2 / g、18m 2 / g、20m 2 / g、23m 2 / g、25m 2 / g、27m 2 / g、29m 2 / g、30m 2 / g or any of the above values. This provides more channels for lithium-ion transport, improving the kinetic performance of the battery cell; and while increasing the energy density of the battery cell, it also suppresses side reactions on the negative electrode, improving the cycle stability of the battery cell.

[0088] In some embodiments, the average outer diameter of the negative electrode active material is 2-20 μm or 3-13 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or any combination of the above values. This reduces the DCR of the battery cell, improving its kinetic performance, and also mitigates the negative impact of excessively small outer diameter on the battery cell's energy density and cycle stability.

[0089] In some embodiments, the average thickness of the shell structure is 0.5-8 μm or 1-7 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or any range of the above values.

[0090] Therefore, while ensuring the energy density of the battery cells, the lithium-ion transport path is shortened, improving the dynamic performance of the battery cells. On the other hand, space is reserved for the volume expansion of silicon, improving the cycle stability of the battery cells.

[0091] In some embodiments, the negative electrode active material is spherical; and / or, the sphericity of the negative electrode active material is 0.5-1 or 0.7-1, for example, 0.5, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 1, or any range of the above values. This reduces the crushing degree of the negative electrode active material particles and enhances their strength.

[0092] In some embodiments, the silicon particles have a particle size of 0.5-8 nm, such as 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm or any combination of the above values.

[0093] Therefore, while ensuring the energy density of the battery cell, the expansion of silicon particle volume is suppressed, thereby improving the cycle stability of the battery cell.

[0094] In some embodiments, the average pore size of the carbon material is 0.8-5 nm, for example, 0.8 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm or any range of the above values.

[0095] In some embodiments, the pore volume of the carbon material is 0.6-1.06 cm³. 3 / g, for example, 0.6cm 3 / g, 0.7cm 3 / g, 0.8cm 3 / g, 0.9cm 3 / g, 1.0cm 3 / g, 1.06cm 3 / g or any range of the above values.

[0096] In some embodiments, the BET specific surface area of ​​the carbon material is 1000-2000 m². 2 / g, for example, 1000m 2 / g、1100m 2 / g、1200m 2 / g, 1500m 2 / g, 1600m 2 / g、1700m 2 / g、1800m 2 / g、1900m 2 / g、2000m 2 / g or any range of the above values.

[0097] Therefore, the average pore size, pore volume and / or specific surface area of ​​the carbon material are within the above range, which provides a larger space for silicon particles, improves the energy density of the battery cell, and at the same time reserves enough space for the expansion of silicon particles, suppresses the side reactions of the negative electrode, and improves the cycle stability of the battery cell.

[0098] In some embodiments, the areal density of the negative active layer is 5-9 mg / cm³. 2 .

[0099] In some embodiments, the mass ratio of the carbon material to silicon particles is 3:7-8:2, for example, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, or any range of the above values. This is beneficial for increasing the energy density of the battery cell while suppressing the expansion of the negative electrode caused by silicon particles, thus improving the cycle stability of the battery cell.

[0100] In some embodiments, the negative electrode active material includes a core and a coating layer covering the core, wherein the carbon material and the silicon particles are disposed in the core, and the coating layer includes carbon; and / or,

[0101] The average thickness of the coating layer is 1-2 nm.

[0102] Therefore, the carbon coating layer helps to improve the conductivity of the negative electrode material.

[0103] This application provides a method for preparing a negative electrode material, comprising the following steps:

[0104] A first mixture is obtained by mixing a resin containing a cyclic structure, a curing agent, a water-in-oil emulsifier, and an oil-phase solvent.

[0105] An aqueous solvent is added to the first mixture and mixed to obtain a water-in-oil emulsion;

[0106] A second mixture is obtained by mixing a hydrophilic surfactant, an oil-in-water emulsifier, a curing agent, and an aqueous solvent.

[0107] The water-in-oil emulsion is added to the second mixture and mixed to obtain an oil-in-water-in-oil emulsion;

[0108] The oil-in-water-in-oil emulsion is subjected to a solidification reaction, followed by solid-liquid separation, and the solid phase is collected.

[0109] The solid material is dried, calcined, and pore-formed to obtain a carbon material.

[0110] Using the carbon material as a substrate, a negative electrode material is obtained by vapor deposition using a silicon source;

[0111] The negative electrode material includes a negative electrode active material, which includes carbon material and silicon particles. The carbon material has a hollow shell structure with channels. The silicon particles are located on the surface of the shell structure and / or within the channels.

[0112] In some embodiments, in the step of preparing the water-in-oil emulsion, a pre-reaction is performed after mixing to obtain the water-in-oil emulsion.

[0113] In some embodiments, during the preparation of the water-in-oil emulsion, the pre-reaction temperature is 70°C-120°C, for example, 70°C, 80°C, 90°C, 100°C, 11°C, 120°C, or any range of the above values; and / or,

[0114] The pre-reaction time is 0-60 min, for example 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, or any range of the above values.

[0115] In some embodiments, during the step of preparing the carbon material, the drying temperature is 60°C-120°C, for example, 60°C, 70°C, 80°C, 90°C, 100°C, 11°C, 120°C, or any range of the above values; and / or,

[0116] The drying time is 4-24 hours, for example, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, or any range of the above values; and / or,

[0117] Dry under vacuum conditions.

[0118] In some embodiments, during the step of preparing the carbon material, the calcination temperature is 900℃-980℃, for example, 900℃, 910℃, 920℃, 950℃, 960℃, 970℃, 980℃, or any range of the above values; and / or,

[0119] The roasting time is 4-8 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or any range of the above values.

[0120] In some embodiments, the pore-forming process in the step of preparing the carbon material is water vapor pore-forming.

[0121] In some embodiments, during the step of preparing the carbon material, the water vapor flow rate for water vapor pore formation is 0.1-0.5 L / min, for example, 0.1 L / min, 0.2 L / min, 0.3 L / min, 0.4 L / min, 0.5 L / min, or any range of the above values; and / or,

[0122] The control pressure for steam aeration is 5-30 MPa, for example, 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, or any range of the above values; and / or,

[0123] The steam pore-forming time is 4-16 hours, for example, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours or any combination of the above values.

[0124] In some embodiments, in the step of preparing the solid, the curing temperature is the curing temperature of the resin containing the cyclic structure.

[0125] In some embodiments, during the step of preparing the solid, the curing reaction temperature is 50°C-80°C, for example, 50°C, 60°C, 70°C, 80°C, or any range of the above values; and / or,

[0126] The curing reaction time is 3-12 hours, for example, 3 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours or any range of the above values.

[0127] In some embodiments, in the step of preparing the first mixture, the mass ratio of the cyclic resin to the curing agent is 10:2.3-10:0.7, for example, 10:2.3, 10:2.1, 10:2.0, 10:1.8, 10:1.6, 10:1.4, 10:1.2, 10:1, 10:0.9, 10:0.8, 10:0.7 or any range of the above values.

[0128] In some embodiments, in the step of preparing the first mixture, the mass ratio of the cyclic resin to the water-in-oil emulsifier is 10:5-10:1, for example, 10:5, 10:4, 10:3, 10:2, 10:1 or any range of the above values.

[0129] In some embodiments, in the step of preparing the first mixture, the mass ratio of the cyclic resin to the oil phase solvent is 10:4 to 10:0.5, for example, 10:4, 10:3, 10:2, 10:1, 10:0.5 or any range of the above values.

[0130] In some embodiments, in the step of preparing the first mixture, the resin containing the cyclic structure includes one or more resins containing aliphatic heterocycles and their homologues.

[0131] In some embodiments, in the step of preparing the first mixture, the resin containing the cyclic structure includes one or more epoxy resins and their homologues.

[0132] In some embodiments, in the step of preparing the first mixture, the resin containing the cyclic structure includes one or more epoxy resins.

[0133] In some embodiments, in the step of preparing the water-in-oil emulsion, the aqueous solvent is added dropwise to the first mixture and mixed.

[0134] In some embodiments, in the step of preparing the water-in-oil emulsion, the mass ratio of the aqueous solvent to the first mixture is 1:16.28 to 7:16.28, for example, 1:16.28, 2:16.28, 3:16.28, 4:16.28, 5:16.28, 6:16.28, 7:16.28 or any range of the above values.

[0135] In some embodiments, in the step of preparing the second mixture, the mass ratio of the hydrophilic surfactant to the curing agent is 0.1:1.28 to 1.5:1.28, for example, 0.1:1.28, 0.2:1.28, 0.3:1.28, 0.5:1.28, 0.6:1.28, 0.8:1.28, 1:1.28, 1.2:1.28, 1.3:1.28, 1.5:1.28, or any range of the above values.

[0136] In some embodiments, in the step of preparing the second mixture, the mass ratio of the oil-in-water emulsifier to the curing agent is 9:1.28-12.5:1.28, for example, 9:1.28, 10:1.28, 11:1.28, 12:1.28, 12.5:1.28 or any range of the above values.

[0137] In some embodiments, in the step of preparing the second mixture, the mass ratio of the curing agent to the aqueous solvent is 1.28:10-1.28:2, for example, 1.28:10, 1.28:9, 1.28:8, 1.28:7, 1.28:6, 1.28:5, 1.28:4, 1.28:3, 1.28:2 or any range of the above values.

[0138] In some embodiments, in the step of preparing the oil-in-water-in-oil emulsion, the oil-in-water emulsion is added dropwise to the second mixture and mixed.

[0139] In some embodiments, in the step of preparing the water-in-oil emulsion, the mass ratio of the water-in-oil emulsion to the second mixture is 10:122-30:122, for example, 10:122, 11:122, 13:122, 15:122, 16:122, 17:122, 18:122, 20:122, 22:122, 23:122, 25:122, 26:122, 27:122, 28:122, 29:122, 30:122, or any range of the above values.

[0140] In some embodiments, the silicon source in the step of preparing the negative electrode active material is a silicon-containing gas.

[0141] In some embodiments, the silicon source in the step of preparing the negative electrode active material includes one or more of silane and halosilane.

[0142] In some embodiments, the silicon source in the step of preparing the negative electrode active material includes one or more of silane, silane, propane, halosilane, halosilane, and halopropane.

[0143] In some embodiments, the silicon source in the step of preparing the negative electrode active material includes one or more of silane, silane, propane, monochlorosilane, dichlorosilane, trichlorosilane, and tetrachlorosilane.

[0144] In some embodiments, during the step of preparing the negative electrode active material, the silicon source flow rate of the vapor deposition is 0.5-5 L / min, for example, 0.5 L / min, 1 L / min, 2 L / min, 3 L / min, 4 L / min, 5 L / min or any range of the above values.

[0145] In some embodiments, during the step of preparing the negative electrode active material, the vapor deposition temperature is 550-600°C, for example, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, or any range of the above values; and / or,

[0146] The vapor deposition time is 3-12 hours, for example, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours or any range of the above values.

[0147] In some embodiments, in the step of preparing the negative electrode active material, the protective gas for the vapor deposition is an inert gas and / or nitrogen; and / or,

[0148] The protective gas flow rate for the vapor deposition is 0.5-30 L / min.

[0149] In some embodiments, the method further includes: coating the surface of the vapor-deposited product with carbon after vapor deposition to obtain a negative electrode active material containing a carbon coating layer.

[0150] In some embodiments, in the step of preparing the negative electrode active material containing the carbon coating layer, carbon is coated on the surface of the vapor-deposited product using a vapor-phase precipitation or solid-phase synthesis method.

[0151] In some embodiments, in the step of preparing the anode active material containing the carbon coating, the vapor deposition temperature is 450-600°C; and / or,

[0152] The vapor deposition time is 2-14 hours; and / or,

[0153] The carbon source used in vapor deposition includes one or more of alkanes, alkenes, and alkynes.

[0154] In some embodiments, the curing agent is the curing agent corresponding to the resin containing the ring structure.

[0155] In some embodiments, the curing agent independently comprises one or more of triethylenetetramine, methacrylamide, and stearic acid tetracarboxylic anhydride.

[0156] In some embodiments, the water-in-oil emulsifier includes one or more of Span-80, polyglycerol esters, and diglycerides.

[0157] In some embodiments, the oil phase solvent includes one or more glycerol ethers; optionally, the oil phase solvent includes one or more of polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, and neopentyl glycol diglycidyl ether.

[0158] In some embodiments, the aqueous solvent includes one or more of water, alcohol, and ketone.

[0159] In some embodiments, in the steps of preparing the first mixture and preparing the water-in-oil emulsion, the mixing temperature is independently 20-80°C, for example, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or any combination of the above values.

[0160] In some embodiments, the mixing in the steps of preparing the first mixture and preparing the water-in-oil emulsion is carried out under stirring conditions.

[0161] In some embodiments, the stirring speed is independently 1500-1700 r / min in the steps of preparing the first mixture and preparing the water-in-oil emulsion.

[0162] In some embodiments, the hydrophilic surfactant includes one or more of sodium dodecyl sulfate and polyglycerol-10 octyl decanoate.

[0163] In some embodiments, the oil-in-water emulsifier includes one or more of OP-10 and polysorbate.

[0164] In some embodiments, the mixing temperature in the steps of preparing the second mixture and preparing the oil-in-water-in-oil emulsion is independently 40-90°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or any combination of the above values.

[0165] In some embodiments, the mixing is carried out under stirring conditions in the steps of preparing the second mixture and preparing the oil-in-water-in-oil emulsion.

[0166] In some embodiments, the stirring rate is independently 300-500 r / min in both the steps of preparing the second mixture and preparing the oil-in-water-in-oil emulsion.

[0167] In some embodiments, the reaction is carried out under stirring conditions during the step of preparing the solid.

[0168] In some embodiments, during the preparation of the carbon material, the solid phase is washed before drying.

[0169] In some embodiments, the method further includes: classifying, sieving, and demagnetizing the negative electrode material.

[0170] In some embodiments, the negative electrode active material prepared by the method is the aforementioned negative electrode material.

[0171]

Positive Electrode

[0172] 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.

[0173] 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.

[0174] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0175] 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 may 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 oxide may 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 NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0176] During the charging and discharging process of a battery, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of cathode materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. When the cathode material is applied to the battery system, the molar Li content changes after charge-discharge cycles.

[0177] In the examples of cathode materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of O will fluctuate.

[0178] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0179] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0180] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0181] [Negative electrode plate]

[0182] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0183] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0184] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0185] 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.

[0186] This application provides a negative electrode material, including a negative electrode active material, wherein the negative electrode active material comprises carbon material and silicon particles, the carbon material is a hollow shell structure, the shell structure is provided with channels, and the silicon particles are located on the surface of the shell structure and / or in the channels.

[0187] Therefore, this application utilizes a carbon material with an internal hollow shell structure and silicon particles located on the surface and / or within the shell pores of the carbon material to form a negative electrode active material. This not only increases the energy density of the battery cell but also reduces the DCR of the battery cell, shortens the charging time, and improves the kinetic performance of the battery cell. Furthermore, the internal hollow structure provides space for the volume expansion of the silicon particles, reducing the volume change of the negative electrode sheet, thereby improving the cycle stability of the battery cell.

[0188] In some embodiments, the BET specific surface area of ​​the negative electrode material is 0.2-30 m². 2 / g or 0.5-3m 2 / g, for example 0.2m 2 / g, 0.5m 2 / g, 0.8m 2 / g, 0.9m 2 / g, 1m 2 / g, 1.2m 2 / g, 1.4m 2 / g, 1.6m 2 / g, 1.9m 2 / g、2m 2 / g, 2.5m 2 / g、3m 2 / g、4m 2 / g、5m 2 / g、6m 2 / g、7m 2 / g、8m 2 / g、9m 2 / g, 10m 2 / g、14m 2 / g, 16m 2 / g、18m 2 / g、20m 2 / g、23m 2 / g、25m 2 / g、27m 2 / g、29m 2 / g、30m 2 / g or any range of the above values.

[0189] In some embodiments, the average outer diameter of the negative electrode active material is 2-20 μm or 3-13 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or any range of the above values.

[0190] In some embodiments, the average thickness of the shell structure is 0.5-8 μm or 1-7 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or any range of the above values.

[0191] In some embodiments, the negative electrode active material is spherical; and / or, the sphericity of the negative electrode active material is 0.5-1 or 0.7-1, for example, 0.5, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 1 or any range of the above values.

[0192] In some embodiments, the silicon particles have a particle size of 0.5-8 nm, such as 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm or any combination of the above values.

[0193] In some embodiments, the average pore size of the carbon material is 0.8-5 nm, for example, 0.8 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm or any range of the above values.

[0194] In some embodiments, the pore volume of the carbon material is 0.6-1.06 cm³. 3 / g, for example, 0.6cm 3 / g, 0.7cm 3 / g, 0.8cm 3 / g, 0.9cm 3 / g, 1.0cm 3 / g, 1.06cm 3 / g or any range of the above values.

[0195] In some embodiments, the BET specific surface area of ​​the carbon material is 1000-2000 m². 2 / g, for example, 1000m 2 / g、1100m 2 / g、1200m 2 / g, 1500m 2 / g, 1600m 2 / g、1700m 2 / g、1800m 2 / g、1900m 2 / g、2000m 2 / g or any range of the above values.

[0196] In some embodiments, the areal density of the negative active layer is 5-9 mg / cm³. 2 .

[0197] In some embodiments, the mass ratio of the carbon material to the silicon particles is 3:7-8:2, for example, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2 or any range of the above values.

[0198] In some embodiments, the negative electrode active material includes a core and a coating layer covering the core, wherein the carbon material and the silicon particles are disposed in the core, and the coating layer includes carbon; and / or,

[0199] The average thickness of the coating layer is 1-2 nm.

[0200] 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 negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0201] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0202] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0203] In some embodiments, the negative electrode film layer may optionally include a binder. As an example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0204] In some embodiments, the negative electrode film may optionally include a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0205] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0206] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0207] Electrolytes

[0208] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0209] Liquid electrolytes include electrolyte salts and solvents.

[0210] In some embodiments, the electrolyte salt may be selected from 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.

[0211] In some embodiments, the solvent may be selected from at least one of 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 of 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.

[0212] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0213] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid—lithium salt.

[0214] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0215] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0216] As an example, inorganic solid electrolytes can be 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-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0217] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0218]

Isolation Components

[0219] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0220] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0221] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0222] 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.

[0223] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0224] [Structure of the Electrode Assembly]

[0225] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0226] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0227] In some implementations, the electrode assembly is a stacked structure.

[0228] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0229] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0230] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0231] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0232] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0233] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0234] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0235]

shell

[0236] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0237] As an example, the 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 prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0238] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0239] Electrode terminals

[0240] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0241] Pressure relief mechanism

[0242] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0243] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby creating an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0244] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0245] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0246] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0247] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0248] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0249] [Battery Device]

[0250] 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.

[0251] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0252] 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 an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0253] 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.

[0254] 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.

[0255] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0256] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0257] 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.

[0258] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0259] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0260] Figure 1 The example shown is a square-structured battery cell 5.

[0261] In some implementations, refer to Figure 2 The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. The positive electrode, negative electrode, and separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in a single battery cell 5 may be one or more, which can be selected by those skilled in the art according to specific practical needs.

[0262] In some implementations, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0263] Figure 3 This is battery module 4, used as an example. (See reference...) Figure 3 In battery module 4, multiple battery cells 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple battery cells 5 can be fixed in place using fasteners.

[0264] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0265] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0266] Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0267] In addition, this application also provides an electrical device, which includes at least one of the battery cell, battery module, or battery pack provided in this application. The battery cell, battery module, or battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0268] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0269] Figure 6 This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of individual battery cells, a battery pack or battery module can be used.

[0270] [Example]

[0271] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0272] Example 1

[0273] (1) Preparation of negative electrode active material:

[0274] ① Weigh 10g of epoxy resin E51, 1.28g of triethylenetetramine, 3g of water-in-oil emulsifier Span-80, and 2g of polypropylene glycol diglycidyl ether into a 100mL beaker, and stir and mix them evenly at 1700r / min at 40℃ to obtain the first mixture.

[0275] ② Add 4g of distilled water dropwise to the first mixture and stir thoroughly at 1600r / min at 70℃ to emulsify. Pre-react at 80℃ for 60min to obtain a water-in-oil emulsion.

[0276] ③ Weigh 100g of distilled water, 0.5g of sodium dodecyl sulfate, 11.5g of oil-in-water emulsifier dodecylphenol polyoxyethylene ether OP-10, and 10g of triethylenetetramine into a 250mL beaker, and stir and mix them evenly in an oil bath at 80℃ at a speed of 500r / min to obtain the second mixture.

[0277] ④ The water-in-oil emulsion prepared above is added dropwise to the second mixture and stirred and dispersed thoroughly at 70°C and a speed of 1200 r / min to obtain an oil-in-water-in-oil emulsion.

[0278] ⑤ Stir the oil-in-water-in-oil emulsion continuously at 400 r / min for 6 hours at 60℃ to allow the epoxy resin to fully cure, then filter and collect the filter residue.

[0279] ⑥ After washing the filter residue, it was vacuum dried at 100℃ for 24 hours to obtain epoxy resin hollow microspheres. The epoxy resin hollow microspheres were then calcined in a muffle furnace under nitrogen protection at 900℃ for 6 hours to obtain the calcined product. The calcined product was subjected to steam pore formation at a steam flow rate of 0.2 L / min, a controlled pressure of 20 MPa, and a steam pore formation time of 8 hours to obtain the carbon material.

[0280] ⑦ Using carbon materials as the substrate, SiH4 as the silicon source, and argon as the protective gas, vapor deposition was carried out in a fluidized bed apparatus. The flow rate of SiH4 gas was 2 L / min; the flow rate of the protective gas was 13 L / min; the vapor deposition temperature was 580℃; and the time was 6 hours to obtain the initial product.

[0281] ⑧ Using ethylene gas as a carbon source, a carbon layer is deposited onto the surface of the primary product via vapor deposition at a temperature of 480℃ for 6 hours, after which the gas source is turned off for cooling. The negative electrode active material is obtained through airflow classification, sieving, and demagnetization.

[0282] like Figures 7A-7B As shown, the negative electrode active material includes carbon material and silicon particles. The carbon material has a hollow shell structure with pores within the shell, and the silicon particles are located on the surface of the carbon material and / or within the pores. The BET specific surface area of ​​the negative electrode material is 1.6 m². 2 The average outer diameter of the negative electrode active material is 9 μm. The negative electrode active material is spherical with a sphericity of 0.85. The average shell thickness is 2 nm. The average pore size of the carbon material is 2.3 nm, and the pore volume is 0.87 cm³. 3 / g, BET specific surface area is 1800m² 2 / g. The particle size of the silicon particles is 0.5-5nm. The mass ratio of carbon material to silicon particles is 49%.

[0283] (2) Preparation of the positive electrode sheet:

[0284] LiNi, the positive electrode active material 0.96 Co 0.03 Mn 0.01 O2, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) are dissolved in solvent N-methylpyrrolidone (NMP) at a mass ratio of 97:1:2 and thoroughly mixed to prepare a positive electrode slurry. The positive electrode slurry is then uniformly coated onto the positive electrode current collector aluminum foil, and subsequently dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0285] (3) Preparation of negative electrode sheet:

[0286] A negative electrode active material, conductive carbon black, styrene-butadiene rubber (SBR) binder, sodium carboxymethyl cellulose (CMC-Na) thickener, and single-walled carbon nanotubes (SWCNTs) were dissolved in deionized water at a mass ratio of 94.5:1:3:1:0.5 and thoroughly mixed to prepare a negative electrode slurry. The negative electrode slurry was coated onto a copper foil current collector, followed by drying, cold pressing, and slitting to obtain the negative electrode sheet. The negative electrode sheet includes a negative electrode current collector and negative electrode active layers located on both sides of the current collector. The areal density of the negative electrode active layers is 8 mg / cm³. 2 .

[0287] (4) Separation membrane: Polypropylene membrane is used as the base membrane, coated with cross-linked sodium carboxymethyl cellulose (CCS) with a thickness of 1 μm, and then coated with polycarbosilane (PCS) with a thickness of 1 μm.

[0288] (5) Preparation of electrolyte: Ethyl carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), and fluoroethylene carbonate (FEC) were mixed in a volume ratio of 1:1:1:1. Then, LiPF6 was uniformly dissolved in the above solution to obtain the electrolyte. The concentration of LiPF6 in the electrolyte was 1 mol / L.

[0289] (6) Preparation of battery cell: The above positive electrode sheet, separator and negative electrode sheet are stacked and wound in sequence to obtain electrode assembly; the electrode assembly is placed in outer packaging, the electrolyte prepared above is added, and after encapsulation, standing, formation and aging processes, battery cell is obtained.

[0290] Examples 2-17 and Comparative Examples 1-2 are similar to the battery cell preparation methods in Example 1, with different product parameters detailed in Table 1-2.

[0291] Parameter testing

[0292] BET specific surface area testing method for negative electrode materials: The negative electrode sheet is disassembled from the battery, thoroughly cleaned with DMC (dimethyl carbonate), and dried. The negative electrode material on the negative electrode current collector is collected by scraping. Referring to GB / T19587-2017, the nitrogen adsorption specific surface area analysis method is used to test the negative electrode material, and the BET (Brunauer-Emmett-Teller) specific surface area is calculated using the BET method. The nitrogen adsorption specific surface area analysis can be performed using a Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA.

[0293] Method for testing the average outer diameter of negative electrode active materials: Disassemble the negative electrode sheet from the battery, thoroughly clean it with DMC (dimethyl carbonate), and dry it. Collect the negative electrode material on the negative electrode current collector using a scraping method. Scan the negative electrode material using SEM. Because the morphology of the negative electrode active material particles differs from that of other components (conductive agent, binder, thickener) in the negative electrode material, the particles can be distinguished. Measure the outer diameter of the negative electrode active material particles from multiple random directions in the SEM image. Then, repeat the above test on more than 50 negative electrode active material particles, and take the average value as the average outer diameter. Divide the shortest outer diameter of the same negative electrode active material particle by the longest outer diameter to obtain the sphericity of the negative electrode active material.

[0294] The method for testing the average thickness of the shell structure is as follows: The negative electrode sheet is disassembled from the battery, thoroughly cleaned with DMC (dimethyl carbonate), and dried. The negative electrode material on the current collector is collected using a scraping method. The negative electrode material is scanned using SEM. Because the morphology of the negative electrode active material particles differs from that of other components (conductive agent, binder, thickener) in the negative electrode material, the particles can be distinguished. The negative electrode active material particles are cut open, and the cut surfaces are scanned using SEM. The shell thickness of the negative electrode active material particles is measured from multiple random directions in the SEM image. This test is repeated with more than 50 negative electrode active material particles, and the average value is taken as the average thickness of the shell structure, in micrometers. Since silicon particles are nanometer-sized, they have almost no impact on the test of the average thickness of the shell structure.

[0295] Methods for testing the BET specific surface area, average pore size, and pore volume of carbon materials: The BET specific surface area, average pore size, and pore volume of carbon materials were tested using a Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA.

[0296] The particle size testing method for silicon particles involves disassembling the negative electrode sheet from the battery, thoroughly cleaning it with DMC (dimethyl carbonate), and drying it. The negative electrode material on the current collector is collected using a scraping method. Scanning the negative electrode material with SEM allows for the identification of the active material. Since carbon materials differ from silicon particles in size and morphology, silicon particles can be distinguished. The particle size of at least 50 silicon particles is measured from the SEM images.

[0297] Method for testing the areal density of the negative electrode active layer: Disassemble the negative electrode sheet from the battery, take a certain area of ​​the negative electrode sheet, thoroughly clean the negative electrode sheet with DMC (dimethyl carbonate) and dry it, collect the negative electrode material on the negative electrode current collector by the powder scraping method, weigh the mass of the negative electrode material, and then divide it by the area of ​​the negative electrode sheet to obtain the areal density of the negative electrode active layer.

[0298] Method for testing the average thickness of the coating layer in the negative electrode active material: Disassemble the negative electrode sheet from the battery, thoroughly clean it with DMC (dimethyl carbonate), and dry it. Collect the negative electrode material on the negative electrode current collector using a scraping method. Scan the negative electrode material with TEM. Because the morphology of the negative electrode active material particles differs from that of other components (conductive agent, binder, thickener) in the negative electrode material, the particles can be distinguished. Cut open a negative electrode active material particle, scan the cut surface with TEM, and measure the coating layer thickness of the negative electrode active material particle from multiple random directions in the scanning electron microscope image. Repeat the above test with multiple negative electrode active material particles, and take the average value as the average thickness of the coating layer in the negative electrode active material.

[0299] Battery test

[0300] (1) Energy density testing method for individual battery cells:

[0301] Incubate the battery cell at 25°C for 2 hours, ensuring the temperature remains at 25°C. Charge at 0.1C at 25°C until the charging cutoff voltage of 4.25V, then continue constant-voltage charging at this cutoff voltage until the current reaches 0.05C, at which point charging is complete (where C represents the battery's rated capacity). Incubate the battery cell at 25°C for 1 hour, then discharge at 0.1C at 25°C until the discharge cutoff voltage of 2.5V, recording the total discharge energy as E0. Place the battery cell on an electronic balance until its weight stabilizes, and read the battery weight value M0 (generally, the battery cell with its casing is weighed). Calculate the energy density of the battery cell using the following formula:

[0302] Energy density of a single battery cell = battery discharge energy E0 / battery weight M0.

[0303] (2) Test method for charging time of individual battery cells from 10% to 80% SOC:

[0304] Voltage calibration:

[0305] The battery cells were left to stand at 25°C for 30 minutes, then charged at 0.33C to the charging cutoff voltage of 4.25V. Constant voltage charging was continued at this charging cutoff voltage until the current reached 0.05C, at which point charging was stopped (where C represents the battery's rated capacity). After standing at 25°C for 1 hour, the battery cells were discharged at 0.33C to the discharge cutoff voltage of 2.5V at 25°C. The total discharge capacity C1 of the battery was recorded.

[0306] Charging test:

[0307] The battery cells were left to stand at 25°C for 30 minutes, then charged with C1 to 4.25V, and then discharged with 0.33C1 until the discharge cutoff voltage of 2.5V. After standing for 5 minutes, they were charged with xC1 until the anode potential reached 0V, at which point the process proceeded to the next step (using a three-electrode monitoring system for the anode potential). This process of standing and charging was repeated a total of 9 times, with x values ​​of 5, 4, 4.5, 3, 2, 1, 0.8, 0.5, and 0.33, respectively. The sum of all charging times was recorded as the 10%–80% SOC charging time.

[0308] (3) Cycle performance testing methods for individual battery cells:

[0309] Voltage calibration:

[0310] The battery cells were left to stand at 25°C for 2 hours to ensure the temperature remained at 25°C. At 25°C, the battery cells were charged at 0.33C to 4.25V, and then charged at a constant voltage of 4.25V until the current reached 0.05C. After standing for 1 hour, the cells were discharged at 0.33C to 0.95C at 25°C, and the voltage V1 was recorded. After standing for 5 minutes, the cells were discharged at 0.33C to 2.0V at 25°C. After standing for 5 minutes, the cells were charged at 0.33C to 0.97C at 25°C, and the voltage V2 was recorded.

[0311] Loop testing:

[0312] The individual battery cells were left to stand at 25°C for 2 hours to ensure the temperature remained at 25°C. At 25°C, the cells were charged to voltage V2 at 0.33C. After standing for 0.5 hours, the cells were discharged to voltage V1 at 0.33C at 25°C. The capacity at this point was recorded as C. n After resting for 0.5 hours, repeat the above charge and discharge operation and record the number of cycles when the battery reaches 80% SOC.

[0313] The test results are shown in Table 3-7.

[0314] Table 1: Differences between the preparation methods of Examples 2-17 and Comparative Examples 1-2 and Example 1

[0315]

[0316]

[0317]

[0318] The "*" distinguishing steps also include adjusting the average outer diameter of the negative electrode active material by controlling the degree of crushing of the raw epoxy resin.

[0319]

[0320] Table 3: Comparison of test results between Examples 1-17 and Comparative Examples 1-2

[0321]

[0322] It can be seen from the above table:

[0323] Compared with the carbon material with a non-hollow structure used in Comparative Example 1, the battery cells of Examples 1-17 of this application have shorter fast charging times and significantly improved dynamic performance.

[0324] Compared with Comparative Example 2, which uses a non-hollow carbon material and a smaller average outer diameter of the negative electrode active material, the cycle life of the battery cells in Examples 1-17 of this application is significantly extended.

[0325] Table 4: Comparison of test results between Examples 1-3 and Examples 4-5

[0326]

[0327]

[0328] It can be seen from the above table:

[0329] Compared with Example 4, which uses a smaller specific surface area of ​​negative electrode material, the battery cells of Examples 1-3 of this application have higher energy density, significantly better kinetic performance, and significantly longer cycle life.

[0330] Compared with Example 5, which uses a larger negative electrode active specific surface area, the battery cells of Examples 1-3 of this application have higher energy density and significantly longer cycle life.

[0331] Table 5: Comparison of test results between Examples 1, 6-7 and Examples 8-9

[0332]

[0333] It can be seen from the above table:

[0334] Compared with the smaller average outer diameter of the negative electrode active material in Example 8, the energy density and cycle life of the battery cells in Examples 1 and 6-7 of this application are significantly improved.

[0335] Compared with the negative electrode active material of Example 9, which has a larger average outer diameter, the kinetic performance of the battery cells of Examples 1 and 6-7 of this application is significantly improved.

[0336] Table 6: Comparison of test results between Examples 1, 10-11 and Examples 12-13

[0337]

[0338]

[0339] It can be seen from the above table:

[0340] Compared to the thinner average shell thickness of Example 12, the energy density and cycle life of the battery cells in Examples 1, 10-11 of this application are significantly higher.

[0341] Compared to the thicker average shell thickness of Example 13, the kinetic performance of the battery cells in Examples 1 and 10-11 of this application is significantly better.

[0342] Table 7: Comparison of test results between Example 1 and Example 17

[0343]

[0344] As can be seen from the table above, compared with Example 17 which does not have a carbon coating layer, the energy density of the battery cell in Example 1 of this application is significantly higher and the cycle life is significantly longer.

[0345] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, comprising a negative electrode sheet, the negative electrode sheet comprising a negative current collector and a negative active layer located on at least one side of the negative current collector, the negative active layer comprising a negative electrode material, the negative electrode material comprising a negative active material, the negative active material comprising a carbon material and silicon particles, the carbon material having an internally hollow shell structure, the shell structure having channels, and the silicon particles located on the surface of the shell structure and / or within the channels.

2. The battery cell according to claim 1, wherein, The BET specific surface area of ​​the negative electrode material is 0.2-30 m². 2 / g or 0.5-3m 2 / g.

3. The battery cell according to claim 1 or 2, wherein, The average outer diameter of the negative electrode active material is 2-20 μm or 3-13 μm.

4. The battery cell according to any one of claims 1 to 3, wherein, The average thickness of the shell structure is 0.5-8 μm or 1-7 μm.

5. The battery cell according to any one of claims 1 to 4, wherein, The negative electrode active material is spherical; and / or, The sphericity of the negative electrode active material is 0.5-1 or 0.7-1.

6. The battery cell according to any one of claims 1 to 5, characterized in that... One or more of the following: The silicon particles have a particle size of 0.5-8 nm; The carbon material has an average pore size of 0.8-5 nm; The carbon material has a pore volume of 0.6-1.06 cm³. 3 / g; The BET specific surface area of ​​the carbon material is 1000-2000 m². 2 / g; The areal density of the negative active layer is 5-9 mg / cm³. 2 .

7. The battery cell according to any one of claims 1 to 6, wherein, The mass ratio of the carbon material to the silicon particles is 3:7-8:

2.

8. The battery cell according to any one of claims 1 to 7, wherein, The negative electrode active material includes a core and a coating layer covering the core, wherein the carbon material and the silicon particles are disposed in the core, and the coating layer includes carbon; and / or, The average thickness of the coating layer is 1-2 nm.

9. A negative electrode material, comprising a negative electrode active material, the negative electrode active material comprising carbon material and silicon particles, the carbon material having an internally hollow shell structure, the shell structure having channels, and the silicon particles being located on the surface of the shell structure and / or within the channels.

10. The negative electrode material according to claim 9, wherein, The BET specific surface area of ​​the negative electrode material is 0.2-30 m². 2 / g or 0.5-3m 2 / g.

11. The negative electrode material according to claim 9 or 10, wherein, The average outer diameter of the negative electrode active material is 2-20 μm or 3-13 μm.

12. The negative electrode material according to any one of claims 9 to 11, wherein, The average thickness of the shell structure is 0.5-8 μm or 1-7 μm.

13. The negative electrode material according to any one of claims 9 to 12, wherein, The negative electrode active material is spherical; and / or, The sphericity of the negative electrode active material is 0.5-1 or 0.7-1.

14. The negative electrode material according to any one of claims 9 to 13, characterized in that... One or more of the following: The silicon particles have a particle size of 0.5-8 nm; The carbon material has an average pore size of 0.8-5 nm; The carbon material has a pore volume of 0.6-1.06 cm³. 3 / g; The BET specific surface area of ​​the carbon material is 1000-2000 m². 2 / g; The mass ratio of the carbon material to the silicon particles is 3:7-8:

2.

15. The negative electrode material according to any one of claims 9 to 14, wherein, The negative electrode active material includes a core and a coating layer covering the core, wherein the carbon material and the silicon particles are disposed in the core, and the coating layer includes carbon; and / or, The average thickness of the coating layer is 1-2 nm.

16. A method for preparing a negative electrode material, comprising the following steps: A first mixture is obtained by mixing a resin containing a cyclic structure, a curing agent, a water-in-oil emulsifier, and an oil-phase solvent. An aqueous solvent is added to the first mixture and mixed to obtain a water-in-oil emulsion; A second mixture is obtained by mixing a hydrophilic surfactant, an oil-in-water emulsifier, a curing agent, and an aqueous solvent. The water-in-oil emulsion is added to the second mixture and mixed to obtain an oil-in-water-in-oil emulsion; The oil-in-water-in-oil emulsion is subjected to a solidification reaction, followed by solid-liquid separation, and the solid phase is collected. The solid material is dried, calcined, and pore-formed to obtain a carbon material. Using the carbon material as a substrate, a negative electrode material is obtained by vapor deposition using a silicon source; The negative electrode material includes a negative electrode active material, which includes carbon material and silicon particles. The carbon material has a hollow shell structure with channels. The silicon particles are located on the surface of the shell structure and / or within the channels.

17. The method according to claim 16, wherein, In the step of preparing the water-in-oil emulsion: A pre-reaction is performed after mixing to obtain a water-in-oil emulsion; and / or, The pre-reaction temperature is 70℃-120℃; and / or, The pre-reaction time is 0-60 min.

18. The method according to claim 16 or 17, wherein, In the steps of preparing the carbon material: The calcination temperature is 900℃-980℃; and / or, The roasting time is 4-8 hours; and / or, The pore-forming method is steam pore-forming.

19. The method according to any one of claims 16 to 18, wherein, In the steps of preparing the solid: The curing temperature is the curing temperature of the resin containing the cyclic structure; and / or, The curing reaction takes 3-12 hours.

20. The method according to any one of claims 16 to 19, characterized in that... One or more of the following: In the step of preparing the first mixture, the mass ratio of the cyclic resin to the oil phase solvent is 10:4-10:0.

5. In the step of preparing the water-in-oil emulsion, the mass ratio of the aqueous solvent to the first mixture is 1:16.28-7:16.28; In the step of preparing the oil-in-water-in-oil emulsion, the mass ratio of the oil-in-water emulsion to the second mixture is 10:122-30:

122.

21. The method according to any one of claims 16 to 20, wherein, In the steps of preparing the negative electrode active material: The silicon source flow rate for the vapor deposition is 0.5-5 L / min; and / or, The vapor deposition temperature is 550-600℃; and / or, The vapor deposition time is 3-12 hours.

22. The method according to any one of claims 16 to 21, further comprising: After vapor deposition, carbon is coated onto the surface of the vapor deposition product to obtain a negative electrode active material containing a carbon coating layer.

23. The method according to any one of claims 16 to 22, characterized in that... One or more of the following: The curing agent is the curing agent corresponding to the resin containing the ring structure; The water-in-oil emulsifier includes one or more of Span-80, polyglycerol ester, and diglyceride; The hydrophilic surfactant includes one or more of sodium dodecyl sulfate and polyglycerol-10 octyl caprylate; The oil-in-water emulsifier includes one or more of OP-10 and polysorbate; The negative electrode material prepared by the method is the negative electrode material described in any one of claims 1 to 15.

24. A battery device comprising a battery cell according to any one of claims 1 to 8, a negative electrode material according to any one of claims 9 to 15, or a negative electrode material prepared by any one of claims 16 to 23.

25. An electrical device comprising a battery cell as described in any one of claims 1 to 8 or a battery device as described in claim 24.

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