Preparation method of bottom supporting plate

Abstract

The invention provides a preparation method of a bottom supporting plate. The preparation method of the bottom supporting plate comprises the steps that slurry is prepared and comprises a base material, a heat conduction filler and a solvent, and the content of the base material is larger than that of the heat conduction filler; an external field is applied to the slurry, the heat conduction filler is directionally arranged in the preset direction and forms a green body, and the external field comprises at least one of a magnetic field, an electric field, a temperature gradient field and a flow field. According to the technical scheme, the preparation method of the bottom supporting plate can solve the problem that a bottom supporting plate of an existing battery is poor in heat conduction performance.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a method for preparing a base plate. Background Technology

[0002] With the growing global demand for green mobility and sustainable energy, electric vehicles (EVs) are experiencing rapid development as an important mode of transportation. The performance of the battery system, a core component of EVs, especially in terms of fast charging technology, faces both significant challenges and opportunities. Fast charging technology allows EVs to replenish their charge quickly, greatly improving vehicle availability and user experience. However, as the driving range of EVs increases and charging rates accelerate, the heat generated by high-capacity battery cells during high-rate (≥1.5C) charging also increases significantly.

[0003] The base plate of existing batteries is usually made of polypropylene (PP) or other polymer materials. These materials are favored for their light weight, low cost and good insulation properties. However, these polymer materials have low thermal conductivity, generally less than 0.5 W / (m·K), which makes the thermal conductivity of the base plate poor. This has become a key bottleneck restricting the rapid heat dissipation of the battery cell and seriously affects the heat dissipation during the charging and discharging cycle of the battery. Summary of the Invention

[0004] The main objective of this invention is to provide a method for preparing a base plate that can solve the problem of poor thermal conductivity of existing battery base plates.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a base plate is provided, comprising: preparing a slurry, the slurry comprising a matrix material, a thermally conductive filler and a solvent, wherein the content of the matrix material is greater than the content of the thermally conductive filler; applying an external field to the slurry to orient the thermally conductive filler along a preset direction to form a green body, wherein the external field comprises at least one of a magnetic field, an electric field, a temperature gradient field and a flow field.

[0006] Furthermore, the thermally conductive filler includes at least one of magnetic field responsive filler, electric field responsive filler, temperature gradient field responsive filler, and flow field responsive filler; and / or, the matrix material includes at least one of aluminum nitride, alumina, and polyetheretherketone.

[0007] Furthermore, the magnetic field response filler uses at least one of boron nitride nanotubes, iron with an insulating layer on the surface, nickel with an insulating layer on the surface, and iron(III) oxide with an insulating layer on the surface; the insulating layer uses one of silicon dioxide, polydopamine, polystyrene, epoxy resin, and alumina film; the electric field response filler uses at least one of graphene, ceramic dielectric, and polymer dielectric; the temperature gradient field response filler uses at least one of hexagonal boron nitride, paraffin wax, graphene, carbon nanotubes, boron nitride, poly(N-isopropylacrylamide), and gallium-based alloy; and the flow field response filler uses at least one of carbon fiber, boron nitride sheet, alumina sheet, mica sheet, silicon carbide fiber, and alumina fiber.

[0008] Further, the step of applying an external field to the slurry to orient the thermally conductive filler along a preset direction and form a green body includes: allowing the slurry to flow into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s under the action of a magnetic field with a magnetic induction intensity of 2T to 20T and a magnetic field direction of the preset direction; heating the slurry to a temperature of 70℃ to 90℃ to form a green body; or, allowing the slurry to flow into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; applying a magnetic field with a magnetic induction intensity of 4T to 6T and a magnetic field direction of the preset direction to the slurry; and heating the slurry to a temperature of 70℃ to 90℃ to form a green body.

[0009] Further, the step of applying an external field to the slurry to orient the thermally conductive filler along a predetermined direction and form a green body includes: injecting the slurry into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; gradually decreasing the temperature of the receiving structure from its bottom to its top to form a temperature gradient field in the thickness direction of the slurry; or, injecting the slurry into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; applying an electric field in a predetermined direction to the slurry, wherein the strength of the electric field is 0.8 kV / cm to 1.2 kV / cm and the frequency of the electric field is 0.8 kHz to 1.2 kHz.

[0010] Furthermore, the method for preparing the base plate also includes: forming an auxiliary heat dissipation structure on the green blank. The step of forming the auxiliary heat dissipation structure on the green blank includes: cutting the green blank into a preset size; scanning the surface of the green blank with a laser along a preset path or spraying a coating onto the surface of the green blank along a preset path to form the auxiliary heat dissipation structure.

[0011] Furthermore, the method for preparing the base plate also includes: forming an auxiliary heat dissipation structure on the green blank. The step of forming the auxiliary heat dissipation structure on the green blank includes: cutting the green blank into a preset size; placing the green blank into a mold and making the bottom surface of the green blank contact with the bottom surface of the inner cavity of the mold, wherein the bottom surface of the inner cavity of the mold is provided with a structure identical to the auxiliary heat dissipation structure; heating the green blank so that the heating temperature is higher than the melting point of the base material and lower than the melting point of the thermally conductive filler; and applying a pressure of 10MPa to 20MPa to the green blank.

[0012] Furthermore, the method for preparing the base plate also includes: densifying the green blank; and forming at least one of an insulating layer, a hydrophobic coating, and a toughening layer on the surface of the green blank.

[0013] Furthermore, the slurry also includes sintering aids. The densification process for the green body includes: placing the green body in the receiving cavity of the debinding equipment, raising the temperature of the receiving cavity to 530℃~570℃ at a heating rate of 1℃ / min~3℃ / min and holding it at that temperature for 1.5h~2.2h; transferring the green body to a nitrogen atmosphere sintering furnace, raising the temperature to 1700℃~1740℃ at a heating rate of 3℃ / min~6℃ / min and holding it at that temperature for 1.5h~2.2h.

[0014] Furthermore, the slurry also includes sintering aids and binders. The steps for preparing the slurry include: mixing the matrix material, sintering aids, binders and solvents to form a mixture, wherein the mass percentage of the matrix material ranges from 80wt% to 92wt%, the mass percentage of the sintering aid ranges from 3wt% to 5wt%, and the sum of the mass percentages of the binder and solvent ranges from 3wt% to 5wt%; adding thermally conductive fillers to the mixture, and making the mass percentage of the thermally conductive fillers 5wt% to 10wt%.

[0015] Using the technical solution of this invention, the matrix material is used to form the main structure of the green blank. The heat of the battery cell can be transferred to the main structure, then conducted from the main structure to the casing, and then from the casing to the outside of the battery. However, the thermal conductivity direction of the main structure formed by the matrix material cannot be controlled. This application adds thermally conductive filler to the matrix material. The thermally conductive filler can also conduct the heat from the battery cell to the base plate to the casing, and then from the casing to the outside of the battery. Under the action of an external field, the thermally conductive filler can be oriented in the matrix material according to a preset direction (the preset direction refers to the thermal conductivity direction), forming a thermal conductivity path extending along the preset direction, thereby further improving the thermal conductivity of the base plate. For example, if you want to improve the thermal conductivity efficiency of the battery cell to the base plate, you can apply an external field to the slurry to make the thermally conductive filler align along the thickness direction of the base plate. In this way, the heat of the battery cell can be quickly transferred to the base plate, improving the heat dissipation performance of the battery. This application achieves the directional arrangement of thermally conductive fillers by applying an external field (e.g., magnetic field, electric field, temperature gradient field, or flow field) to the slurry. After directional arrangement, a thermally conductive path can be formed along a preset direction, thereby greatly improving the thermal conductivity and efficiency of the base plate in a specific direction. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A flowchart illustrating a method for preparing a base plate according to an embodiment of the present invention is shown. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] With the increasing demand for fast charging technology in electric vehicles, large-capacity battery cells generate a significant amount of heat during high-speed (≥1.5C) charging. Existing batteries mostly use polymer materials such as polypropylene (PP) for their base plates, which have extremely low thermal conductivity (typically <0.5 W / (m·K)), becoming a major bottleneck for heat dissipation at the bottom of the battery cell. Accumulated heat can lead to excessively high cell temperatures, reduced lifespan, and even the risk of thermal runaway.

[0020] To solve the above problems, such as Figure 1The present invention provides a method for preparing a base plate, the method comprising: preparing a slurry, the slurry comprising a matrix material, a thermally conductive filler and a solvent, wherein the content of the matrix material is greater than the content of the thermally conductive filler; applying an external field to the slurry to cause the thermally conductive filler to be oriented along a preset direction and form a green body, wherein the external field comprises at least one of a magnetic field, an electric field, a temperature gradient field and a flow field.

[0021] In this embodiment, the battery typically includes a casing, a battery cell, and a base plate. Both the battery cell and the base plate are installed inside the casing. The base plate is located at the bottom of the casing and directly contacts the battery cell. The base plate supports the battery cell, ensuring its stable positioning within the battery casing and preventing movement or deformation during battery use. It also conducts heat generated by the battery cell during charging and discharging to the casing and then from the casing to the outside of the battery, preventing heat accumulation inside the battery and thus avoiding excessively high battery temperatures. The green blank formed by oriented the thermally conductive filler along a predetermined direction is an anisotropic thermally conductive green blank, meaning its thermal conductivity varies in different directions.

[0022] The matrix material is used to form the main structure of the green blank. The heat from the battery cell can be transferred to the main structure, then from the main structure to the casing, and then from the casing to the outside of the battery. However, the thermal conductivity direction of the main structure formed by the matrix material cannot be controlled. This application adds thermally conductive filler to the matrix material. The thermally conductive filler can also conduct the heat from the battery cell to the base plate to the casing, and then from the casing to the outside of the battery. Under the action of an external field, the thermally conductive filler can be oriented in the matrix material according to a preset direction (the preset direction refers to the thermal conductivity direction), forming a thermal conductivity path extending along the preset direction, thereby further improving the thermal conductivity of the base plate. For example, to improve the thermal conductivity efficiency of the battery cell's heat transfer to the base plate, an external field can be applied to the slurry to make the thermally conductive filler align along the thickness direction of the base plate. In this way, the heat from the battery cell can be quickly transferred to the base plate, improving the battery's heat dissipation performance.

[0023] The matrix material content is greater than the thermally conductive filler content, enabling the base plate prepared by the method of this application to maintain good mechanical properties while possessing strong thermal conductivity. This application achieves the directional arrangement of the thermally conductive filler by applying an external field (e.g., magnetic field, electric field, temperature gradient field, or flow field) to the slurry. After directional arrangement, a thermal conduction path can be formed along a predetermined direction, thereby greatly improving the thermal conductivity and efficiency of the base plate in a specific direction.

[0024] It should be noted that the preset direction can be the Z-axis direction (i.e., the thickness direction of the base plate) or an in-plane direction (X-axis and / or Y-axis direction). If the goal is to improve the lateral and / or longitudinal heat conduction capacity from the inside of the battery core to the outside of the core or from the base plate to the aluminum shell, then the in-plane direction will be set as the preset direction. For example, through an external field, the thermally conductive filler can be oriented along the X-axis or Y-axis direction to form an efficient heat conduction path on the plane of the base plate. The preset direction also does not have to be a simple linear direction, but a more complex direction designed according to the distribution of battery heat sources and the layout of the cooling system.

[0025] In addition, the flow field in this application refers to the application of specific shear force or pressure by controlling the flow rate and direction of fluids (such as coolant, etching solution, etc.) so that the thermally conductive filler can be oriented in the matrix material in a predetermined direction to form a thermally conductive path extending along the predetermined direction.

[0026] In one embodiment of the present invention, the thermally conductive filler includes at least one of magnetic field responsive filler, electric field responsive filler, temperature gradient field responsive filler, and flow field responsive filler.

[0027] In this embodiment, different types of thermally conductive fillers require the application of corresponding external fields to form an oriented arrangement. Magnetic field responsive fillers can be oriented in a predetermined direction within the matrix material under the influence of a magnetic field; electric field responsive fillers can be oriented in a predetermined direction within the matrix material under the influence of an electric field; temperature gradient field responsive fillers can be oriented in a predetermined direction within the matrix material under the influence of a temperature gradient field; and flow field responsive fillers can be oriented in a predetermined direction within the matrix material under the influence of a flow field. Through these settings, a heat conduction path with a predetermined direction can be formed under the influence of an external field, improving the thermal conductivity of the base plate.

[0028] In one implementation, the magnetic field responsive filler is at least one of boron nitride nanotubes, iron with an insulating layer on the surface, nickel with an insulating layer on the surface, and iron(III) oxide with an insulating layer on the surface, and the insulating layer is one of silicon dioxide, polydopamine, polystyrene, epoxy resin, and aluminum oxide film.

[0029] It should be noted that the iron mentioned above refers to iron particles or powder, the nickel mentioned above refers to nickel particles or powder, and the iron(III) oxide mentioned above refers to iron(III) oxide particles or powder.

[0030] The electric field responsive filler uses at least one of graphene, ceramic dielectrics (e.g., barium titanate, strontium titanate, lead zirconate titanate), and polymer dielectrics (e.g., polyvinylidene fluoride, liquid crystal polymer).

[0031] The temperature gradient field responsive filler uses at least one of the following: hexagonal boron nitride, paraffin wax, graphene, carbon nanotubes, boron nitride, poly(N-isopropylacrylamide), and gallium-based alloys.

[0032] The flow field response filler uses at least one of the following: carbon fiber, boron nitride sheet, alumina sheet, mica sheet, silicon carbide fiber, and alumina fiber.

[0033] In one embodiment of the present invention, the external field further includes at least one of an acoustic field and a centrifugal force field, wherein the acoustic field achieves the directional alignment of the thermally conductive filler through ultrasound, and the centrifugal force field achieves the directional alignment of the thermally conductive filler through centrifugal force. The thermally conductive filler also includes at least one of an acoustic field-responsive filler and a centrifugal force field-responsive filler. The acoustic field-responsive filler may be at least one of hollow glass microspheres and solid ceramic particles (such as Al2O3 and ZnO), and the centrifugal force field-responsive filler may be at least one of zirconium oxide and alumina.

[0034] It should be noted that other materials in the prior art can also be used for magnetic field responsive packing, as long as they can achieve directional arrangement under the action of a magnetic field. Other materials in the prior art can also be used for electric field responsive packing, as long as they can achieve directional arrangement under the action of an electric field. Other materials in the prior art can also be used for temperature gradient field responsive packing, as long as they can achieve directional arrangement under the action of a temperature gradient field. Other materials in the prior art can also be used for flow field responsive packing, as long as they can achieve directional arrangement under the action of a flow field.

[0035] In one embodiment of the present invention, the matrix material includes at least one of aluminum nitride, aluminum oxide, and polyetheretherketone.

[0036] In this embodiment, the matrix material includes at least one of aluminum nitride, aluminum oxide, and polyetheretherketone (PEEK). Aluminum nitride and aluminum oxide, as ceramic materials, have good hardness and wear resistance, which can maintain the structural stability of the base plate during the battery's life. PEEK, as a high-performance thermoplastic, has excellent mechanical strength and rigidity, which can withstand the weight of the battery cell and the vibration and impact during battery use. Aluminum nitride and aluminum oxide have good thermal conductivity, which can effectively and quickly conduct the heat generated by the battery cell during charging and discharging to the surface of the base plate, thereby accelerating heat dissipation. Aluminum nitride, aluminum oxide, and PEEK all have good electrical insulation properties, which can prevent electrical short circuits between the battery cell and the base plate, ensuring the safety and stability of the battery's internal structure.

[0037] In one embodiment of the present invention, the step of applying an external field to the slurry to orient the thermally conductive filler along a preset direction and form a green body includes: causing the slurry to flow into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s under the action of a magnetic field with a magnetic induction intensity of 2T to 20T and a magnetic field direction of a preset direction; and heating the slurry at a temperature of 70°C to 90°C to form a green body.

[0038] In this embodiment, the thermally conductive filler includes a magnetic field-responsive filler (e.g., boron nitride nanotubes), which can be oriented in a predetermined direction within the matrix material under the influence of a magnetic field. The magnetic induction intensity is in the range of 4T to 6T, effectively acting on the magnetically responsive filler to orient it along the magnetic field direction, forming a thermally conductive path in the predetermined direction and improving the thermal conductivity of the base plate. Setting the slurry flow rate to 1.8 mm / s to 2.2 mm / s ensures both uniform distribution of the slurry in the receiving structure and that the oriented arrangement of the magnetically responsive filler is not affected.

[0039] Heating the slurry at a temperature of 70℃~90℃ can accelerate the evaporation of the solvent and promote the solidification of the slurry, thereby stabilizing the directional arrangement of the magnetic field responsive filler and preventing the magnetic field responsive filler from redistributing randomly during subsequent processing (such as drying and sintering), thus forming a structurally stable green body.

[0040] In one embodiment of the present invention, the step of applying an external field to the slurry to orient the thermally conductive filler along a preset direction and form a green body includes: flowing the slurry into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; applying a magnetic field with a magnetic induction intensity of 4 T to 6 T and a magnetic field direction in a preset direction to the slurry; and heating the slurry at a heating temperature of 70°C to 90°C to form a green body.

[0041] In this embodiment, the thermally conductive filler includes a magnetic field-responsive filler (e.g., boron nitride nanotubes), which can be oriented in a predetermined direction within the matrix material under the influence of a magnetic field. A magnetic induction intensity in the range of 4T to 6T effectively acts on the magnetically responsive filler, causing it to oriented along the magnetic field direction, forming a thermally conductive path in the predetermined direction and improving the thermal conductivity of the base plate. Setting the slurry flow rate to 1.8mm / s to 2.2mm / s ensures both uniform distribution of the slurry in the container structure and prevents the oriented arrangement of the magnetically responsive filler from being affected. Heating the slurry at a temperature of 70℃ to 90℃ accelerates solvent evaporation and promotes slurry solidification, thereby stabilizing the oriented arrangement of the magnetically responsive filler and preventing its random redistribution during subsequent processing (such as drying and sintering), resulting in a structurally stable green body.

[0042] In one embodiment of the present invention, the step of applying an external field to the slurry to orient the thermally conductive filler along a preset direction and form a green body includes: injecting the slurry into the bonding structure at a speed of 1.8 mm / s to 2.2 mm / s; and gradually decreasing the temperature of the bonding structure from its bottom to its top to form a temperature gradient field in the thickness direction of the slurry.

[0043] In this embodiment, the thermally conductive filler includes a temperature gradient field responsive filler (e.g., hexagonal boron nitride), which can be oriented in a predetermined direction within the matrix material under the action of a temperature gradient field. By gradually decreasing the temperature of the bonding structure from bottom to top, a temperature gradient field can be formed in the thickness direction of the slurry. This causes the temperature gradient field (e.g., hexagonal boron nitride) in the slurry to migrate due to density differences caused by temperature changes. During cooling, the temperature gradient field responsive filler tends to move from high-temperature regions to low-temperature regions. Since the temperature gradually decreases from top to bottom during slurry curing, this process promotes the oriented arrangement of the temperature gradient field responsive filler along the thickness direction, which can improve the thermal conductivity of the base plate in its thickness direction.

[0044] Injecting the slurry into the bonding structure at a speed of 1.8 mm / s to 2.2 mm / s ensures that the temperature gradient field has sufficient time for the filler to respond to the effect of the temperature gradient field and oriented during the slurry injection process. At the same time, it can also maintain the structural uniformity of the green body, thereby ensuring the uniformity of thermal conductivity and the reliability of the structure.

[0045] It should be noted that the above-mentioned holding structure can use containers with existing technology; the specific structure will not be described in detail here.

[0046] In one embodiment of the present invention, the step of applying an external field to the slurry to orient the thermally conductive filler along a preset direction and form a green body includes: injecting the slurry into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; applying an electric field in a preset direction to the slurry, wherein the strength of the electric field is 0.8 kV / cm to 1.2 kV / cm and the frequency of the electric field is 0.8 kHz to 1.2 kHz.

[0047] In this embodiment, the thermally conductive filler includes an electric field-responsive filler (e.g., graphene), which can be oriented in a predetermined direction within the matrix material under the influence of an electric field. When an electric field is applied to the slurry, particularly an alternating electric field (electric field strength of 0.8 kV / cm to 1.2 kV / cm, frequency of 0.8 kHz to 1.2 kHz), the electric field-responsive filler can be oriented in a predetermined direction within the matrix material, thereby improving the thermal conductivity of the base plate in that predetermined direction. The selection of the frequency and intensity of the alternating electric field directly affects the microstructure of the electric field-responsive filler arrangement, and can control the formation of an ordered or semi-ordered structure by the electric field-responsive filler.

[0048] Controlling the slurry injection speed within the range of 1.8 mm / s to 2.2 mm / s ensures that, under the applied electric field, the electric field-responsive filler in the slurry is uniformly distributed and oriented along the direction of the electric field. This speed range provides sufficient flow time for the electric field-responsive filler to align in response to the electric field, while maintaining the stability and structural uniformity of the slurry.

[0049] In one embodiment of the present invention, the method for preparing the base plate further includes: forming an auxiliary heat dissipation structure on the green blank.

[0050] In this embodiment, the auxiliary heat dissipation structure can be a microneedle array, corrugations, fins, or microchannels, which can significantly increase the contact surface area between the base plate and the cooling medium (air, liquid), thereby accelerating the heat exchange process.

[0051] The fins can adopt the structure of heat dissipation fins in the existing technology. The specific structure will not be described in detail here. The microneedle array includes multiple cones with a ripple structure similar to a sine wave. The microchannels include multiple straight segments with a length of 0.1μm~500μm, a width of 0.1μm~150μm, and a height of 0.1μm~200μm. The multiple straight segments are arranged in parallel, and adjacent straight segments are arranged with intervals.

[0052] In one embodiment, at least one surface of the green blank can be processed using a digital subtractive manufacturing process or a digital additive manufacturing process based on a two-dimensional or three-dimensional digital model of the auxiliary heat dissipation structure to form the auxiliary heat dissipation structure. The digital subtractive manufacturing process can include laser ablation, which uses a focused high-energy laser beam to remove specific portions of the material surface. When the laser beam is focused on the material surface, its energy is rapidly absorbed, causing a localized temperature increase. The material melts, vaporizes, or chemically decomposes in that area, thereby being removed.

[0053] Digital additive manufacturing can be achieved through slurry direct writing or Digital Light Processing (DLP). Slurry direct writing is an additive manufacturing technology that uses a slurry containing functional particles as "ink," which is then deposited layer by layer through a precisely controlled extrusion head to form complex three-dimensional structures. Digital Light Processing (DLP) is an additive manufacturing method based on photopolymerization technology. It uses a digital light processor (usually a DLP projector) to project ultraviolet or visible light onto a photosensitive resin, curing the resin layer by layer to build a three-dimensional object. DLP technology uses a light-initiated polymerization reaction to cure the photosensitive resin, forming the desired microstructure. Its core component is a DLP projector, which projects a computer-designed two-dimensional slice image onto the resin surface. When the photoinitiator in the resin is triggered by light of a specific wavelength (usually ultraviolet or visible light of a specific wavelength), the resin cures in the irradiated area. This process is performed layer by layer. After each curing, the build platform moves down a certain distance, bringing the newly cured layer into contact with the liquid resin, and then the next photopolymerization is performed until the entire three-dimensional model is completed.

[0054] In one embodiment of the present invention, the step of forming an auxiliary heat dissipation structure on a green blank includes: cutting the green blank to a preset size; scanning the surface of the green blank with a laser along a preset path or spraying a coating onto the surface of the green blank along a preset path to form the auxiliary heat dissipation structure.

[0055] In this embodiment, the green blank is first cut to a predetermined size to ensure that the material size in subsequent processing matches the installation size of the battery module or cell, reducing material waste and facilitating subsequent batch processing and standardized production. Then, a laser is used to scan the cut green blank. During this process, the laser beam moves along a preset path to perform local heat treatment on the surface of the green blank. Through ablation, engraving, or local structural modification, an auxiliary heat dissipation structure can be formed on the surface of the green blank.

[0056] Alternatively, alumina can be selected as the coating and sprayed onto the surface of the green blank according to a preset path to form an auxiliary heat dissipation structure on the surface of the green blank, thereby accelerating the heat exchange rate and effectively improving the heat dissipation efficiency of the base plate.

[0057] In one embodiment, the auxiliary heat dissipation structure is a microneedle array, which includes multiple cones with a bottom diameter of 0.1 mm and a height of 0.12 mm. The multiple cones are arranged in a rhomboid pattern, and the center distance between two adjacent cones is 0.4 mm. The rhomboid arrangement of the multiple cones can ensure the uniform distribution of the microneedle array, avoid local areas being too dense or too sparse, thereby ensuring the uniformity of the heat dissipation area of ​​the base plate and avoiding the formation of hot spots.

[0058] The process utilizes a 355nm wavelength ultraviolet laser to scan the surface of the green substrate along a preset path to form a microneedle array. The short wavelength and high energy density of the ultraviolet laser enable precise material removal at the micrometer scale. A laser power of 12W ensures efficient microneedle array processing while controlling the heat-affected zone, preventing unnecessary damage to surrounding materials. A laser scanning speed of 500mm / s helps control heat accumulation in each microneedle, avoiding structural deformation due to overheating. An 80kHz pulse frequency ensures laser continuity in the processing area. Continuous pulse impact on the material allows for finer and more controllable material removal, contributing to a smooth microneedle surface. A 30% overlap rate ensures sufficient contact between laser processing paths, preventing micropores or discontinuous structures caused by gaps between laser spots, thus improving the integrity and precision of the microneedle array. The preset path can be programmed; the laser scans and removes material layer by layer along the preset path, ultimately forming the microneedle array.

[0059] In one embodiment of the present invention, the method for preparing the base plate further includes: forming an auxiliary heat dissipation structure on the green blank. The step of forming the auxiliary heat dissipation structure on the green blank includes: cutting the green blank into a preset size; placing the green blank into a mold and making the bottom surface of the green blank contact with the bottom surface of the inner cavity of the mold, wherein the bottom surface of the inner cavity of the mold is provided with a structure identical to the auxiliary heat dissipation structure; heating the green blank so that the heating temperature is higher than the melting point of the base material and lower than the melting point of the thermally conductive filler; and applying a pressure of 10MPa to 20MPa to the green blank.

[0060] In this embodiment, the green blank is cut to a preset size. This step ensures that the bottom support plate formed by the green blank can be inserted into the battery casing and can support the battery cell. The cut green blank is placed in the inner cavity of the mold, with the bottom surface of the green blank in contact with the bottom surface of the inner cavity of the mold. The green blank is heated so that the heating temperature is higher than the melting point of the matrix material but lower than the melting point of the thermally conductive filler. This softens and flows the matrix material without melting the thermally conductive filler, thereby maintaining the microstructure and thermal conductivity of the thermally conductive filler. At the same time, a pressure of 10MPa to 20MPa is applied to the green blank. Under the action of pressure, the bottom surface of the green blank in the softened state can completely fit with the auxiliary heat dissipation structure set on the bottom surface of the inner cavity of the mold, thereby forming an auxiliary heat dissipation structure on the bottom surface of the green blank.

[0061] In one embodiment, the raw material is cut into a preset size, wherein the preset size is 290mm~295.4mm in length and 2.2mm~2.8mm in width.

[0062] In one embodiment of the present invention, the method for preparing the base plate further includes: densifying the green blank; and forming at least one of an insulating layer, a hydrophobic coating, and a toughening layer on the surface of the green blank.

[0063] In this embodiment, the insulating layer is formed primarily to ensure that a short circuit does not occur between the base plate and other conductive components inside the battery. The hydrophobic coating reduces electrolyte adhesion to the base plate surface and promotes its uniform distribution within the battery. This can be achieved by depositing a low surface energy material, such as fluorinated carbon (CxFy) or silicon fluoride (Si), on the base plate surface. Liquid-repellent coatings can be formed using methods such as chemical vapor deposition (CVD) or plasma-enhanced chemical vapor deposition (PECVD).

[0064] The toughening layer can improve the toughness of the base plate and reduce the damage that may occur during battery assembly and transportation. It can be made of polymers or composite ceramic materials with high toughness properties, such as polysiloxane or silicon carbide ceramics. The toughening layer can be formed by processes such as spraying, dip coating or direct writing of slurry.

[0065] The densification treatments applied to the green blank (such as insulating layers and hydrophobic coatings) significantly improve the reliability of the base plate in the battery's operating environment, reducing the risk of short circuits and performance degradation caused by direct contact between the material and the electrolyte or other internal battery components. These densification treatments (such as toughening layers) also effectively reduce the probability of damage to the base plate under impact or pressure, thereby indirectly improving the battery's lifespan and safety.

[0066] In one embodiment of the present invention, the slurry further includes a sintering aid, and the step of densifying the green body includes: placing the green body in the receiving cavity of the debinding device, raising the temperature of the receiving cavity to 530°C to 570°C at a heating rate of 1°C / min to 3°C / min and holding it at that temperature for 1.5h to 2.2h; transferring the green body to a nitrogen atmosphere sintering furnace, raising the temperature to 1700°C to 1740°C at a heating rate of 3°C / min to 6°C / min and holding it at that temperature for 1.5h to 2.2h.

[0067] In this embodiment, the slurry also includes a sintering aid, which can lower the sintering temperature of the green body. The green body is placed in the receiving chamber of the debinding device for debinding treatment, and the solvent in the slurry is an organic solvent. The green body is placed in the receiving chamber of the debinding device, and the temperature of the receiving chamber is raised to 530℃~570℃ at a heating rate of 1℃ / min~3℃ / min and held for 1.5h~2.2h. This removes the organic components in the slurry, preventing the organic components from decomposing at high temperatures and generating gases that would form bubbles during sintering, resulting in pores inside the green body and a denser structure. At the same time, it also reduces the overall shrinkage rate during sintering, which helps maintain the dimensional accuracy of the base plate.

[0068] Controlling the heating rate to 1℃ / min~3℃ / min and holding at 530℃~570℃ for 1.5h~2.2h ensures uniform decomposition of organic matter without excessively rapid gas generation leading to uneven internal pressure in the green body, thus preventing cracks or porosity. Sintering green bodies containing sintering aids in a nitrogen atmosphere sintering furnace, controlling the heating rate to 3℃ / min~6℃ / min and holding at 1700℃~1740℃ for 1.5h~2.2h, significantly improves the material's density. The nitrogen atmosphere not only prevents oxidation at high temperatures, ensuring the material's chemical stability, but also helps form a purer microstructure, thereby improving the material's mechanical strength and thermal conductivity. Furthermore, the sintering aids lower the sintering temperature, promote interparticle bonding, reduce sintering defects, and further enhance the density and performance of the base plate. Sintering in a nitrogen atmosphere effectively prevents the material from reacting with atmospheric oxygen, maintaining the purity of the material composition.

[0069] In one embodiment, the sintering aid is yttrium oxide (YO). The debinding equipment can adopt the existing debinding furnace. The specific structure will not be described here. The green body is transferred to a nitrogen atmosphere sintering furnace and heated to 1700℃~1740℃ at a heating rate of 3℃ / min~6℃ / min and held at that temperature for 1.5h~2.2h. The green body is then cooled with the furnace, and finally complete densification is achieved.

[0070] In one embodiment of the present invention, the slurry further includes a sintering aid and a binder. The steps for preparing the slurry include: mixing a matrix material, a sintering aid, a binder, and a solvent to form a mixture, wherein the mass percentage of the matrix material ranges from 80wt% to 92wt%, the mass percentage of the sintering aid ranges from 3wt% to 5wt%, and the sum of the mass percentages of the binder and the solvent ranges from 3wt% to 5wt%; adding a thermally conductive filler to the mixture, such that the mass percentage of the thermally conductive filler is 5wt% to 10wt%.

[0071] In this embodiment, a high proportion of matrix material ensures that the final product has a high thermal conductivity. Furthermore, it ensures that the slurry retains good mechanical properties even after organic matter is removed. The sintering aid lowers the sintering temperature and increases the sintering density, allowing for sufficient densification at lower temperatures and avoiding excessive energy consumption from high-temperature equipment. The sum of the mass percentages of binder and solvent, ranging from 3wt% to 5wt%, provides suitable fluidity and stability for the slurry, facilitating molding operations. The thermally conductive filler, with a mass percentage of 5wt% to 10wt%, can be arranged in a predetermined direction by applying an external field, forming more effective heat conduction paths within the material and significantly improving the thermal conductivity of the base plate.

[0072] In one embodiment of the present invention, the densification process of the green blank includes debinding and sintering the green blank before the densification step. Debinding the green blank removes organic components from it. If organic components are not removed first, residual organic components will form pores during sintering, reducing the density of the material and thus affecting thermal conductivity and mechanical strength. Sintering the green blank fuses the particles to form a dense structure, thereby improving the thermal conductivity, mechanical strength, and insulation properties of the material. The densification step of the green blank includes forming an insulating layer on the surface of the green blank. Specifically, the sintered green blank is first double-sided polished to ensure a smooth surface, and then an atomic layer deposition (ALD) technique is used to deposit a dense alumina film (insulating layer) with a thickness of 50 nm on the surface of the green blank, serving as an insulating and electrolyte corrosion resistant barrier.

[0073] In one embodiment, the matrix material is aluminum nitride with a median particle size of 0.5 micrometers, the binder is acrylic resin, and the solvent is an organic solvent (formed by mixing ethanol and toluene). The matrix material, sintering aid, binder, and solvent are mixed to form a mixture and ball-milled for 24 hours. Then, boron nitride nanotubes (BNNTs with a length of 10 μm to 20 μm) that have been ultrasonically dispersed are added, making them account for 5 wt% to 10 wt% of the total solid mass of the slurry. The mixture is then ball-milled again for 8 hours to obtain a high-viscosity, uniformly dispersed slurry.

[0074] The ultrasonic dispersion power is 280W~320W, and the ultrasonic dispersion time is set to 28min~32min. This is to break up the agglomeration between boron nitride nanotubes, so that they are evenly distributed in the slurry, while avoiding structural damage caused by over-dispersion, and ensuring the responsiveness and orientation effect of boron nitride nanotubes in the subsequent magnetic field orientation process.

[0075] In one embodiment of the present invention, the step of heating the slurry to a temperature of 70°C to 90°C to form a green body further includes: reserving 15% for sintering shrinkage. This allows for a certain dimensional increase during the green body preparation process to compensate for shrinkage during sintering, thereby ensuring that the dimensions of the sintered base plate meet the design requirements. The 15% reserved shrinkage means that the prepared green body size is approximately 15% larger than the final target size; thus, after sintering, the size shrinks to the expected size.

[0076] In one embodiment of the present invention, the thermally conductive filler includes a magnetic field-responsive filler, which is made of boron nitride nanotubes. The step of applying an external field to the slurry to orient the thermally conductive filler along a preset direction and form a green body includes: ensuring that the orientation degree of the boron nitride nanotubes meets the half-width at half-maximum (FWHM) requirement (FWHM < 5°) as measured by the XRD rocking curve. This demonstrates that under the action of a magnetic field, the boron nitride nanotubes achieve a high degree of directional alignment in the green body. By controlling the FWHM within 5°, the orientation effect of the boron nitride nanotubes can be guaranteed, thereby ensuring the heat dissipation performance of the base plate.

[0077] X-ray diffraction (XRD) is a commonly used characterization method in materials science to determine the crystal structure, grain size, and orientation of materials. When X-rays irradiate the surface of a material, diffraction occurs according to the crystal structure. The position, intensity, and shape of the diffraction peaks can provide a wealth of information about the material's microstructure. In XRD, a detailed scan of a diffraction peak is typically performed by tilting the instrument to the left and right of the peak and recording the changes in diffraction intensity; this process is called a rocking curve scan. The full width at half maximum (FWHM) refers to the width of the diffraction peak at half its intensity.

[0078] Example 1:

[0079] The external field is a magnetic field, and the auxiliary heat dissipation structure is a microneedle array with a preset direction along the Z-axis. Applicable scenarios include high-end electric vehicle batteries with stringent requirements for fast-charging heat dissipation performance. The microneedle array comprises multiple cones with a bottom diameter of 0.1 mm and a height of 0.12 mm, arranged in a rhomboid pattern. The center-to-center distance between adjacent cones is 0.4 mm.

[0080] Slurry preparation and magnetic field-assisted casting: 92 wt% aluminum nitride (AlN, D50=0.5μm) powder and 3 wt% yttrium oxide (… A sintering aid, 5 wt% acrylic resin binder, and solvent (ethanol / toluene blend) were mixed and ball-milled for 24 hours. Then, boron nitride nanotubes (BNNTs, 10 μm~20 μm in length) that had been ultrasonically dispersed (300 W, 30 min) were added, making them 10 wt% of the slurry. The mixture was ball-milled again for 8 hours to obtain a high-viscosity, uniformly dispersed slurry. The slurry was injected into the casting machine tank and cast at a speed of 2 mm / s under a strong magnetic field (Z-axis direction) of 5 T. The boron nitride nanotubes were oriented along the magnetic field direction (Z-axis) under the influence of the magnetic field. The slurry was dried on a heating plate at 80 °C under continuous magnetic field to obtain a green body with a thickness of 0.33 mm (allowing for approximately 15% sintering shrinkage). The orientation degree of the boron nitride nanotubes was characterized by the half-width at half-maximum (FWHM < 5°) of the XRD rocking curve.

[0081] The green blank was cut to a preset size (295.4mm × 2.8mm). An ultraviolet laser (355nm wavelength) was used to scan and ablate the surface of the green blank according to a preset path. Key laser parameters were: power 12W, scanning speed 500 mm / s, pulse frequency 80kHz, and spot overlap rate 30%. Then, the green blank underwent debinding and sintering. The green blank was placed in a debinding furnace and heated to 550℃ at a rate of 1℃ / min in air atmosphere, held for 2 hours to completely remove the organic carrier. The debinded green blank was then transferred to a nitrogen atmosphere sintering furnace. <5ppm), the temperature is increased to 1720℃ at 5℃ / min, held for 2 hours, and then cooled in the furnace to achieve complete densification. Then, the green billet is polished on both sides to ensure a smooth surface. Atomic layer deposition (ALD) technology is used to deposit a dense alumina film with a thickness of 50nm on the surface of the green billet as an insulating and electrolyte corrosion resistant barrier.

[0082] Example 2:

[0083] The external field is an electric field, and the auxiliary heat dissipation structure is a microchannel. The microchannel includes multiple straight segments with a width of 150μm and a height of 200μm. The multiple straight segments are arranged in parallel, and the distance between two adjacent straight segments is 1mm. The preset directions are the X and Y directions. It is suitable for hybrid cooling systems and needs to be used in conjunction with a liquid cooling plate for battery packs with extremely high requirements for heat dissipation uniformity.

[0084] 85 wt% alumina powder, 5 wt% magnesium oxide (MgO) sintering aid, 10 wt% water-soluble polymer, and deionized water were mixed and ball-milled. 5 wt% graphene sheets were then added and ultrasonically dispersed to form a slurry. The slurry was injected into a casting mold equipped with interdigitated electrodes, and an alternating electric field (1 kV / cm, 1 kHz) was applied. The graphene sheets were polarized due to dielectric electrophoresis, causing their planes to align along the electric field lines (i.e., within the XY plane). The mixture was then dried at low temperature under the influence of the electric field to obtain a green body with in-plane thermal conductivity paths.

[0085] Using a direct-write printer equipped with a 150μm diameter nozzle, and employing high-solids-content, thixotropic alumina as the "ink," microchannels are directly printed onto the surface of the green body oriented by the aforementioned electric field. After printing, the microchannels are cured under mild conditions, bonding them integrally with the green body. The green body with the microchannels is then debonded and sintered. During sintering, the temperature is increased to 1720℃ at a rate of 5℃ / min and held for 2 hours to prevent cracking or deformation due to shrinkage mismatch between the two layers, ultimately forming a one-piece embedded microchannel. The base plate and cover plate can be bonded together to make the microchannel a closed flow channel, or the open microchannel can be directly connected to an external liquid cooling system.

[0086] Example 3:

[0087] The external field is a temperature gradient field, the auxiliary heat dissipation structure is a corrugated structure, and the preset directions are the X and Y directions. It is suitable for mass production and applicable to cost-sensitive medium-range electric vehicles or consumer electronics batteries.

[0088] 25 vol% of hexagonal boron nitride (h-BN) sheets (aspect ratio > 200) are mixed with 75 vol% of polyetheretherketone (PEEK) or high-temperature epoxy resin powder in a solvent to form a slurry. The slurry is cast onto a heating plate, and a temperature gradient is created along the thickness direction of the heating plate by controlling the temperature of the heating plate (e.g., heating the bottom to 100°C and cooling the top to 50°C). Under the action of the temperature gradient field, the hexagonal boron nitride sheets are oriented along the temperature gradient field direction (i.e., within the XY plane). After the solvent in the slurry evaporates, a green blank is obtained. The green blank is cut to a predetermined size (295.4 mm × 2.8 mm) and placed in a preheated mold. One side of the mold cavity is flat (in contact with the battery cell), and the other side is etched with corrugations (e.g., a sine wave with a wavelength of 1.2 mm and a wave height of 0.1 mm). Hot pressing was performed at a temperature above the melting point of polyetheretherketone (380°C) and a pressure of 10 MPa to 20 MPa. The polyetheretherketone melted and flowed, filling the mold cavity, while the orientation of the hexagonal boron nitride (h-BN) sheet was preserved. Finally, the green body with a corrugated structure was obtained by cooling and shaping. Table 1 compares Example 1, Example 2, and Example 3.

[0089] Table 1

[0090]

[0091] The method for preparing the base plate in this application has the following advantages:

[0092] 1) Greater versatility and flexibility: Specifically, this is reflected in: Selectable materials: The matrix material can be aluminum nitride, alumina, or even high-performance polymers; the thermally conductive filler can be boron nitride nanotubes, graphene, carbon fibers, etc.; Adjustable structure: By changing the digital model, auxiliary heat dissipation structures such as microneedles, corrugations, fins, and microchannels can be easily fabricated without changing the core process equipment. Variable field source: The external field can be a magnetic field, electric field, or temperature gradient field, adaptable to different thermally conductive fillers.

[0093] 2) Superior performance, achieving synergistic optimization of thermal conduction and dissipation. This method addresses the heat dissipation problem simultaneously from two physical levels. Specifically: Improving the intrinsic thermal conductivity of the material (fundamental solution): External field-induced directional alignment of thermally conductive fillers constructs a "thermal highway" from the battery cell to the outside, significantly reducing the thermal resistance of the substrate itself. Enhancing surface heat transfer efficiency (symptom-relief): Digital manufacturing creates complex microstructures, increasing the contact area with the cooling medium and inducing turbulence, breaking the boundary layer and significantly enhancing the heat transfer process.

[0094] 3) Ensuring high consistency and precision of products: Utilizing digital manufacturing technologies (laser, direct writing) overcomes the bottlenecks of traditional processes. Specifically: High precision: The processing precision of ultraviolet laser / femtosecond laser can reach the micrometer level, far superior to traditional stamping, etching, and other processes, meeting the stringent requirements of battery cells for interface flatness and structural consistency. High consistency: Digital processing is program-controlled, eliminating the instability of manual operation and ensuring a high degree of consistency in the performance of each base plate, which is crucial for the consistency of the battery module.

[0095] 4) Excellent process compatibility and scalability: This method is compatible with existing ceramic processes and emerging additive manufacturing technologies, making it easy to implement in mass production. Specifically: Integration with existing processes: "Cast casting-sintering" is a mature ceramic process that is easily upgraded and modified on existing production lines. It incorporates digital additive / subtractive manufacturing technologies such as "Direct Direct Writing (DIW)" and "laser processing," giving it future competitiveness.

[0096] 5) Balancing Reliability Design with Multifunctional Integration: The methodology includes steps to enhance product reliability and add additional functionality. Specifically: High Interfacial Bond Strength: Field orientation completes filler arrangement during material preparation, avoiding interfacial thermal resistance and detachment risks associated with later processes such as spraying and bonding. Integrated Surface Functionalization: Post-processing steps (such as ALD deposition) can simultaneously achieve multiple functions such as insulation, corrosion resistance, and wear resistance, improving the overall performance and lifespan of the product.

[0097] 6) Effectively balancing the demands for high performance and low cost: This method provides multiple implementation paths, from high-end to economical. Specifically: High-end market: The solution in Example 1 can be adopted, pursuing high performance. Cost-sensitive market: The solution in Example 3 can be adopted, achieving considerable performance improvements at a highly competitive cost.

[0098] 7) Improved R&D efficiency and reduced development costs: Digital model-driven manufacturing enables rapid iteration. Specifically, when developing new products, there is no need to re-make molds or modify production lines. Simply modify the design model on the computer (such as adjusting the micro-needle spacing or corrugation shape) to quickly prepare samples for verification, greatly shortening the R&D cycle and reducing costs.

[0099] 8) Strong technological foresight and long life cycle: Specifically, no matter what new thermally conductive fillers (such as more advanced carbon nanomaterials) emerge in the future, as long as they can respond to external fields and align in a direction; no matter what more advanced digital manufacturing technologies emerge in the future, as long as they can process green blanks, this method can incorporate them into its technological system, demonstrating strong vitality and foresight.

[0100] 9) Interfaces are reserved for future technological evolution: Specifically, based on this method, the following can be further developed: Intelligent thermal management base plate: Real-time temperature monitoring is achieved by embedding sensing elements in the structure. Differentiated heat dissipation in different areas: Different densities of structures are processed in different areas of the same base plate to achieve targeted enhanced heat dissipation in hot spots.

[0101] Existing technologies have attempted to use metallic or ordinary ceramic materials, but these suffer from problems such as insufficient insulation, mismatch with the thermal expansion coefficient of the battery cell, or inability to achieve complex heat dissipation structures. In particular, how to efficiently and precisely fabricate microscopic heat dissipation structures (such as microneedles or corrugations) on a high thermal conductivity ceramic substrate while ensuring their mechanical strength and insulation reliability is a pressing technical challenge in this field. There is a lack of a universal, high-performance base plate fabrication method that can flexibly adapt to different heat dissipation requirements and battery models. The base plate fabrication method of this application can solve problems such as insufficient insulation, mismatch with the thermal expansion coefficient of the battery cell, or inability to achieve complex heat dissipation structures, while also enabling the fabrication of microscopic heat dissipation structures.

[0102] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: the matrix material is used to form the main structure of the green blank, and the heat of the cell can be transferred to the main structure, then from the main structure to the shell, and then from the shell to the outside of the battery. However, the thermal conductivity direction of the main structure formed by the matrix material cannot be controlled. In this application, thermally conductive filler is added to the matrix material. The thermally conductive filler can also conduct the heat from the cell to the base plate to the shell, and then from the shell to the outside of the battery. Moreover, under the action of an external field, the thermally conductive filler can be oriented in the matrix material according to a preset direction (the preset direction refers to the thermal conductivity direction), forming a thermal conductivity path extending along the preset direction, thereby further improving the thermal conductivity of the base plate. For example, if it is desired to improve the thermal conductivity efficiency of the cell's heat transfer to the base plate, an external field can be applied to the slurry to make the thermally conductive filler align along the thickness direction of the base plate. In this way, the heat of the cell can be quickly transferred to the base plate, improving the heat dissipation performance of the battery. This application achieves the directional arrangement of thermally conductive fillers by applying an external field (e.g., magnetic field, electric field, temperature gradient field, or flow field) to the slurry. After directional arrangement, a thermally conductive path can be formed along a preset direction, thereby greatly improving the thermal conductivity and efficiency of the base plate in a specific direction.

[0103] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0104] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a base plate, characterized in that, include: A slurry is prepared, the slurry comprising a matrix material, a thermally conductive filler, and a solvent, wherein the content of the matrix material is greater than the content of the thermally conductive filler; An external field is applied to the slurry to orient the thermally conductive filler along a preset direction and form a green body. The external field includes at least one of a magnetic field, an electric field, a temperature gradient field, and a flow field.

2. The method for preparing the base plate according to claim 1, characterized in that, The thermally conductive filler includes at least one of magnetic field responsive filler, electric field responsive filler, temperature gradient field responsive filler, and flow field responsive filler; and / or, the matrix material includes at least one of aluminum nitride, aluminum oxide, and polyetheretherketone.

3. The method for preparing the base plate according to claim 2, characterized in that, The magnetic field response filler is made of at least one of boron nitride nanotubes, iron with an insulating layer on the surface, nickel with an insulating layer on the surface, and iron(III) oxide with an insulating layer on the surface. The insulating layer is made of one of silicon dioxide, polydopamine, polystyrene, epoxy resin, and alumina film. The electric field response filler is made of at least one of graphene, ceramic dielectric, and polymer dielectric. The temperature gradient field response filler is made of at least one of hexagonal boron nitride, paraffin wax, graphene, carbon nanotubes, boron nitride, poly(N-isopropylacrylamide), and gallium-based alloy. The flow field response filler is made of at least one of carbon fiber, boron nitride sheet, alumina sheet, mica sheet, silicon carbide fiber, and alumina fiber.

4. The method for preparing the base plate according to any one of claims 1 to 3, characterized in that, The step of applying an external field to the slurry to orient the thermally conductive filler along a predetermined direction and form a green body includes: The slurry is made to flow into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s under the action of a magnetic field with a magnetic induction intensity of 2T to 20T and a magnetic field direction in the preset direction; The slurry is heated to a temperature of 70°C to 90°C to form the green body; or, The slurry is made to flow into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; A magnetic field with a magnetic induction intensity of 4T~6T and a magnetic field direction in the preset direction is applied to the slurry; The slurry is heated to a temperature of 70°C to 90°C to form the green body.

5. The method for preparing the base plate according to any one of claims 1 to 3, characterized in that, The step of applying an external field to the slurry to orient the thermally conductive filler along a predetermined direction and form a green body includes: The slurry is injected into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; The temperature of the receiving structure gradually decreases from its bottom to its top to create a temperature gradient field along the thickness direction of the slurry; or, The slurry is injected into the receiving structure at a speed of 1.8 mm / s to 2.2 mm / s; An electric field in the preset direction is applied to the slurry, wherein the strength of the electric field is 0.8 kV / cm to 1.2 kV / cm, and the frequency of the electric field is 0.8 kHz to 1.2 kHz.

6. The method for preparing the base plate according to any one of claims 1 to 3, characterized in that, The method for preparing the base plate further includes: forming an auxiliary heat dissipation structure on the green blank, wherein the step of forming the auxiliary heat dissipation structure on the green blank includes: The raw material is cut into a preset size; The auxiliary heat dissipation structure is formed by scanning the surface of the green blank with a laser along a preset path or by spraying coating onto the surface of the green blank along a preset path.

7. The method for preparing the base plate according to any one of claims 1 to 3, characterized in that, The method for preparing the base plate further includes: forming an auxiliary heat dissipation structure on the green blank, wherein the step of forming the auxiliary heat dissipation structure on the green blank includes: The raw material is cut into a preset size; The green blank is placed in the mold, and the bottom surface of the green blank is in contact with the bottom surface of the inner cavity of the mold, wherein the bottom surface of the inner cavity of the mold is provided with the same structure as the auxiliary heat dissipation structure; The green body is heated to a temperature higher than the melting point of the matrix material but lower than the melting point of the thermally conductive filler. A pressure of 10 MPa to 20 MPa is applied to the green blank.

8. The method for preparing the base plate according to any one of claims 1 to 3, characterized in that, The method for preparing the base plate also includes: The green body is subjected to densification treatment; At least one of an insulating layer, a hydrophobic coating, and a toughening layer is formed on the surface of the green blank.

9. The method for preparing the base plate according to claim 8, characterized in that, The slurry also includes sintering aids, and the densification treatment of the green body includes: The green body is placed in the receiving cavity of the glue removal device, and the temperature of the receiving cavity is raised to 530℃~570℃ at a heating rate of 1℃ / min~3℃ / min and held for 1.5h~2.2h. The green blank is transferred to a nitrogen atmosphere sintering furnace and heated to 1700℃~1740℃ at a heating rate of 3℃ / min~6℃ / min and held at that temperature for 1.5h~2.2h.

10. The method for preparing the base plate according to any one of claims 1 to 3, characterized in that, The slurry further includes sintering aids and binders, and the steps for preparing the slurry include: The matrix material, the sintering aid, the binder, and the solvent are mixed to form a mixture, wherein the mass percentage of the matrix material ranges from 80wt% to 92wt%, the mass percentage of the sintering aid ranges from 3wt% to 5wt%, and the sum of the mass percentages of the binder and the solvent ranges from 3wt% to 5wt%. The thermally conductive filler is added to the mixture, and the mass percentage of the thermally conductive filler is 5wt%~10wt%.

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