Method for producing graphene composite parts with enhanced thermal conductivity

Abstract

Methods for mass production of graphene composite vehicle parts are provided. The method includes injecting a first flux into a molten metal contained in a furnace using a first flux injection system, and injecting a graphene flux into the molten metal using a second flux injection system. The method includes agitating and homogenizing molten metal and graphene flux within a furnace using an agitator. The method includes transferring molten metal into a mold having an electromagnetic stirring system and then stirring the molten metal with the electromagnetic stirring system until the molten metal solidifies. The electromagnetic stirring system maintains the homogenization of the molten metal and the graphene flux.

Description

Technical Field

[0001] The present disclosure relates to the field of graphene composite materials, and more particularly, to a casting method for forming mass-produced graphene composite materials having a uniformly distributed graphene matrix therein. Background Art

[0002] Aluminum and aluminum alloy materials are used as thermal conductors in many components, such as in electric vehicle battery pack components. Batteries and other vehicle components generate heat within the vehicle battery pack, and the vehicle battery pack must be removed to prevent overheating. In addition, battery pack components are subject to stress and must be structurally sound. When battery pack components contain 1xxx pure aluminum and aluminum alloys, they are affected by grain growth at elevated operating temperatures (50°C-100°C) when subjected to long-term operation. In addition, copper and copper alloy materials are used as electrical conductors in many components.

[0003] While current aluminum and aluminum alloys, and copper and copper alloy components achieve their intended purpose of having thermal and electrical conductivity and providing structural strength and stability, there is a need for methods and systems for manufacturing components having enhanced thermal and electrical conductivity, structural strength, and material thermal stability. Summary of the Invention

[0004] According to another aspect of the present disclosure, the method includes injecting at least one of nitrogen or argon and injecting a first flux during degassing.

[0005] According to another aspect of the present disclosure, the method includes injecting surface-treated graphene having nickel deposited on the graphene when injecting the graphene flux into the molten metal.

[0006] According to another aspect of the present disclosure, the method includes injecting graphene premixed with at least one of graphene aluminum powder or graphene copper powder when injecting the graphene flux into the molten metal.

[0007] According to another aspect of the present disclosure, the method includes using a propeller agitator in stirring and homogenizing the molten metal.

[0008] According to several aspects of the present disclosure, a method for cooling components used in electric vehicles is provided. The method includes injecting a first flux into molten metal in a furnace using a first flux injector. The first flux includes at least one of nitrogen or argon, and the molten metal is degassed by the first flux. The method includes injecting a graphene flux into the molten metal using a second flux injector. The graphene flux is a powder, and the graphene flux includes a surface treatment comprising at least one of nickel or copper. The method includes stirring and homogenizing the molten metal and the graphene flux in the furnace using a propeller stirrer. The method also includes transferring the molten metal into a mold having an electromagnetic stirring system. The electromagnetic stirring system maintains homogenization of the molten metal and the graphene flux. The method also includes stirring the molten metal with the electromagnetic stirring system until the molten metal solidifies at a temperature equal to or less than 660°C, and forming a cooling component for the electric vehicle from the cooled molten metal. The cooling component includes a vehicle battery pack cooling plate.

[0009] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0011] Figure 1 is a simplified schematic diagram illustrating a furnace system for containing and homogenizing graphene-containing molten metal according to the present disclosure.

[0012] Figure 2 The configuration according to the present disclosure is shown as follows Figure 1 The furnace system shown in FIG. 1 is a simplified schematic diagram of a high pressure die casting (HPDC) system receiving molten metal.

[0013] Figure 3A The configuration according to the present disclosure is shown as follows Figure 1 The furnace system shown in FIG is a simplified schematic diagram of an open mold that receives molten metal.

[0014] Figure 3B The configuration according to the present disclosure is shown as follows Figure 1 The furnace system shown in FIG is a simplified schematic diagram of an open mold receiving molten metal with a forming press in place.

[0015] Figure 4 is a side perspective view showing a vehicle having a battery pack assembly according to the present disclosure, the battery pack assembly having a battery pack assembly having a battery pack assembly having a battery pack assembly according to the present disclosure, Figure 1 The furnace system shown and Figures 2 to 3B The mold shown forms the cooling plate.

[0016] Figure 5 It is shown that according to the present disclosure Figure 4 A perspective view of a battery pack assembly having ... Figure 1 The cooling plate formed by the furnace system depicted in FIG.

[0017] Figure 6 It is to show the use according to the present disclosure as Figure 1 The furnace system shown and Figures 2 to 3B Flowchart of a method for mass production of graphene composite vehicle components using a mold as shown. DETAILED DESCRIPTION

[0018] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0019] refer to Figure 1 , a schematic diagram of a simplified furnace system 10 for containing and homogenizing graphene-containing molten metal 12 is shown in accordance with the principles of the present disclosure. The furnace system 10 provides homogeneity within the matrix of the molten metal 12 as graphene or other materials are added. The furnace system 10 includes a furnace 14, a first flux injection system 16, a second flux injection system 18, and an agitator 20.

[0020] like Figure 1 As shown, the furnace system 10 includes at least one furnace 14. The furnace 14 is configured to provide heat to metal, thereby producing molten metal 12. The molten metal 12 may include, for example, a metal or alloy suitable for use in a vehicle (e.g., a vehicle battery pack cooling plate, a vehicle frame, etc.). Some examples of molten metals or alloys may include aluminum and / or copper. In some cases, the cooling temperature of the molten metal may be 600°C or less. The furnace 14 may include, for example, an induction furnace, an electric arc furnace, a crucible furnace, etc.

[0021] refer to Figure 1, a first flux injection system 16 is arranged to provide a first flux 22 to an interior portion of the furnace 14 and into the molten metal 12. The first flux injection system 16 may include a degassing unit having a flux injector 24, such as a graphite tube or a rotating shaft, configured to inject the first flux 22 into the molten metal 12. When the molten metal 12 comprises aluminum, hydrogen can accumulate within the molten aluminum and cause undesirable pores in the final casting. To remove the hydrogen, the flux injector 24 injects the first flux 22, which comprises an inert gas, such as argon or nitrogen, into the molten metal 12. The inert gas adheres to the hydrogen and brings it to the surface for release into the atmosphere. In addition, the molten aluminum oxidizes rapidly. To remove the resulting oxides, the first flux 22 is injected into the molten metal 12 and into the bottom 26 of the furnace 14. The flux adheres to the oxides and is brought to the surface 28 of the molten metal 12 by rising bubbles and is subsequently removed.

[0022] Still refer to Figure 1 The second flux injection system 18 is arranged to provide a graphene flux 30 to an interior portion 32 of the furnace 14 and into the molten metal 12. The second flux injection system 18 includes a second injector 34, such as a graphite tube or a rotating shaft. The second flux injection system 18 injects the graphene flux onto the surface 28 and / or into the molten metal 12.

[0023] The graphene flux 30 includes at least graphene and may include other materials. Graphene can be in various forms, such as graphene sheets, graphene particles, and / or graphene powder. When in the form of graphene sheets, the graphene sheets can be single-layer graphene sheets and / or multi-layer graphene sheets. In some cases, the graphene sheets are formed by electrochemical exfoliation techniques. In one example, the average lateral diameter of the graphene sheets is between 10 nanometers (nm) and 10 micrometers (μm). The size of the graphene sheets is designed to provide the mechanical properties, electrical conductivity, and / or thermal conductivity required for the resulting graphene-aluminum composite component.

[0024] In some cases, graphene flux 30 includes graphene mixed with aluminum (Al) particles, such as aluminum powder (e.g., graphene aluminum powder) and / or copper (Cu) particles (e.g., graphene copper powder). The aluminum and / or copper powder and the graphene can be formed to have opposite charges, which enhances contact between the aluminum and / or copper particles and the graphene sheets and the accumulation of the resulting graphene aluminum composite powder and / or graphene copper composite powder. In addition, the aluminum and / or copper can serve as a carrier for the graphene.

[0025] In some cases, graphene flux 30 includes graphene that has been plasma treated and, for example, has a more negative charge. Plasma treatment of graphene involves altering the original surface properties of the graphene by interacting with the graphene surface using high-energy and reactive radicals in the plasma. Plasma treatment can have various effects on the graphene, including breaking C-C bonds, removing surface atoms, and / or cleaning the graphene surface.

[0026] In some cases, the graphene flux 30 includes graphene that has been surface-treated. Using surface-treated graphene can improve wettability. For example, the graphene surface can include a copper or nickel coating. When surface-treated, the coating material (e.g., copper and / or nickel) can be deposited or applied using methods including electrodeposition, chemical vapor deposition, and / or applying a solution containing the coating material (e.g., nickel sulfate hexahydrate solution) to the graphene.

[0027] refer to Figure 1 The stirrer 20 is arranged to extend into the molten metal 12 in the furnace 14. When the first flux 22 and / or the graphene flux 30 are provided to the molten metal 12, the stirrer 20 rotates and mixes the molten metal 12. Mixing the molten metal 12 promotes homogenization of the graphene flux 30 and transfers the resulting mixture to the mold. In one aspect, the stirrer 20 is a propeller stirrer configured to generate an axial flow within the molten metal 12. It should be understood that the stirrer may include other types of stirrers or impellers, such as parabolic stirrers, spiral stirrers, blade stirrers, etc.

[0028] Now refer to Figure 2 , shows a schematic diagram of a simplified high pressure die casting (HPDC) mold 36. The HPDC mold 36 receives a homogenized molten metal and graphene flux mixture 38 from the furnace system 10. The HPDC mold 36 includes a metal mold 40 having a cavity 42 in the negative shape of the part to be formed and an electromagnetic stirring system 44. The mixture 38 fills the cavity 42, the HPDC mold 36 is sealed, and the mixture 38 is exposed to high pressure (e.g., greater than 1000 bar) until the mixture 38 solidifies.

[0029] An electromagnetic stirring system 44 is disposed within the HPDC mold 36 and uses a magnetic field to generate a rotational Lorentz force and fluid flow in the mixture 38. The magnetic field acts as a non-invasive stirring device within the mixture 38 to maintain the homogenization of the graphene flux 30 until the mixture 38 solidifies. It should be understood that the electromagnetic stirring system 44 may include, for example, an electromagnetic stirrer (EMS) and other systems, such as an electromagnetic brake system (EMBR). In some cases, the electromagnetic stirring system 44 may be connected to the HPDC mold 36 rather than disposed within the HPDC mold 36.

[0030] Figure 3AA schematic diagram of a simplified open mold 46 with an electromagnetic stirring system 44 is shown. The open mold 46 can be used in addition to or in place of the HPDC mold 36. The open mold 46 receives a homogenized molten metal and graphene flux mixture 38 from the furnace system 10. The open mold 46 includes an open die 48, wherein a portion 50 of the open die 48 is in the negative shape of a portion of the part to be formed. The mixture 38 fills the portion 50.

[0031] refer to Figure 3B After the open mold 48 is filled with the mixture 38, a forming press 52 having a negative shape of at least a portion of the part to be formed is applied and pressed into the mixture 38 to form the part and seal the open mold 46 until the mixture 38 solidifies. An electromagnetic stirring system 44 is disposed within the open mold 46 and maintains homogenization of the graphene flux 30 within the mixture 38. In some cases, the electromagnetic stirring system 44 may be connected to the open mold 48 rather than disposed within the open mold 48.

[0032] like Figures 2 to 3B As shown, the HPDC mold 36 or open mold 46 may include a vibration system 54. The vibration system 54 promotes homogenization of the graphene flux 30 within the mixture 38 while providing reduced shrinkage, better morphology, better surface finish, and reduced hot tearing. Additionally, the vibration system 54 can promote significant grain refinement of the casting and increase compressive strength and hardness. In some aspects, the vibration system 54 provides a frequency of 0 to 20 Hertz (Hz) during the casting process. The vibration system 54 can be provided as part of the HPDC mold 36 or open mold 46 or can be connected to and communicate with the HPDC mold 36 or open mold 46.

[0033] Figure 4 A vehicle 56 is shown having a vehicle battery pack assembly 58 with a vehicle battery pack cooling plate 60 formed using the furnace system 10 and the HPDC mold 36 and / or the open mold 46. The battery pack assembly 58 provides power to the vehicle 56. The battery pack assembly 58 is shown with an exemplary vehicle 56, and the vehicle 56 is an electric vehicle or hybrid vehicle having wheels 62 driven by an electric vehicle motor (not shown).

[0034] Now refer to Figure 5, shows a perspective view of a battery pack assembly 58, and the battery pack assembly 58 generally includes a battery pack housing 64, a cooling plate 66, and a plurality of battery cells 68. The battery pack housing 64 generally includes a bottom plate 70 and a plurality of side walls 72. The plurality of side walls 72 extend around the periphery of the bottom plate 70. The bottom plate 70 is a generally flat member and is supported by and mounted to the vehicle 56 using mechanical fasteners (not shown) such as bolts passing through holes in the bottom plate 70. In addition, the battery pack housing 64 may include a top cover (not shown) connected to the plurality of side walls 72. The cooling plate 66 is supported by the bottom plate 70 of the battery pack housing 64. The cooling plate 66 regulates the temperature of the battery pack housing 64 by removing heat that is radiated from the battery or other heat-generating devices and transferred to the cooling plate 66. The cooling plate 66 is an example of a graphene-based cast component using the HPDC mold 36 or open mold 46 with the electromagnetic stirring system 44 disclosed herein.

[0035] Figure 6 The mass production of graphene composite vehicle parts (such as Figure 4 and Figure 5 The method 100 begins at block 102 .

[0036] At block 102, a first flux 22 is injected into the molten metal 12 in the furnace 14 using the first flux injection system 16. Injecting the first flux 22 includes using a flux injector 24 to provide a gas (e.g., argon, nitrogen) or other material below the surface of the molten metal 12. Injecting the first flux 22 may include degassing the molten metal 12, such as degassing hydrogen. Additionally, injecting the first flux 22 may include removing oxides resulting from oxidation of the molten metal 12 (e.g., molten aluminum).

[0037] At block 104, a graphene flux 30 is injected into the molten metal using the second flux injection system 18. Injecting the graphene flux 30 includes using the second injector 34 to provide graphene below and / or on the surface 28 of the molten metal 12. Injecting the graphene flux 30 may include providing graphene in powder and / or flake form so that the graphene can be mixed into the molten metal 12.

[0038] In block 106, the molten metal 12 and the graphene flux 30 in the furnace 14 are stirred and homogenized using the stirrer 20. Stirring the graphene flux 30 and the molten metal 12 includes homogenizing and thoroughly mixing the graphene flux 30 within the mixture 38 using the stirrer 20. Failure to stir and homogenize the graphene flux 30 and molten metal mixture 38 using the stirrer 20 may result in incomplete mixing or separation of the graphene from the molten metal 12, which is undesirable.

[0039] The molten metal 12 is then transferred to a mold (e.g., an HPDC mold 36, an open mold 46) having an electromagnetic stirring system 44 at box 108. Transferring the molten metal 12 includes pouring or otherwise flowing the molten metal mixture 38 into the mold. In some cases, transferring the molten metal 12 may include using a high-pressure system, such as a hydraulic or pneumatic piston or plunger device, to force the molten metal mixture 38 into the HPDC mold. In other cases, transferring the molten metal 12 may include using a pouring process and gravity to flow into the open mold 46.

[0040] At block 110, the molten metal mixture 38 is stirred using the electromagnetic stirring system 44 until the mixture 38 solidifies. The electromagnetic stirring system 44 maintains and promotes homogenization of the molten metal 12 and the graphene flux 30. Without stirring the molten metal mixture 38, the graphene added as the graphene flux 30 may clump, separate, and / or become unevenly distributed within the mixture 38, thereby reducing the benefits of the graphene. In one example, the molten metal mixture 38 is stirred using the electromagnetic stirring system 44 at a frequency of 5 Hertz (Hz) to 20 Hz and an alternating current (AC) of 50 amperes (A) to 300 A. The molten metal mixture 38 is continuously stirred until solidification is complete.

[0041] At block 112, the method 100 may include vibrating the molten metal 12 in the mold using ultrasonic vibrations. The vibration system 54 may be used to provide ultrasonic vibrations to maintain uniform distribution and homogenization of the graphene flux 30 in the molten metal during cooling in the mold (e.g., HPDC mold 36, open mold 46).

[0042] At block 114, the solidified mixture 38 may be formed into a cooling component for an electric vehicle, such as vehicle 56. The cooling component may include a vehicle battery pack cooling plate, such as cooling plate 60. In one example, the HPDC mold 36 is configured to have a negative shape of the cooling component, and the cooling component is formed as the molten metal mixture 38 cools. In another example, the open mold 46 and forming press 52 are configured to have a negative shape of the cooling component, and the forming press 52 is used to press the cooled mixture 38 to form the cooling component as the molten metal mixture 38 cools and / or solidifies.

[0043] At block 116, the method 100 may include releasing the cast metal from the mold after cooling and solidification, wherein the graphene flux is evenly distributed in the cooled metal. The HPDC mold 36 and / or the open mold 46 may include a cover side 74 (i.e., a forming press 52 in the case of the open mold 46) and a movable mold 76 (e.g., Figures 2 to 3B). When the HPDC mold 36 or the open mold 46 is opened, the solidified mixture 38 remains in the movable mold 76. The movable mold 76 includes ejector pins driven by an ejector pin plate (not shown). The ejector pins are used to eject the cast metal from the HPDC mold 36 and / or the open mold 46. The method 100 then ends.

[0044] The present disclosure has many advantages and benefits over prior art systems and methods for producing graphene-based composite parts. For example, using the furnace system 10 with the stirrer 20 provides better dispersion of graphene within the molten metal 12. Additionally, transferring the molten metal 12 from the furnace system 10 to the HPDC mold 36 or the open mold 46 with the electromagnetic stirring system 44 provides better dispersion of graphene within the molten metal 12 until the molten metal 12 solidifies. This better dispersion of graphene throughout the solidified cast part provides a part with improved thermal and electrical conductivity.

[0045] This description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or use. The broad teachings of the present disclosure can be implemented in many forms. Therefore, although this disclosure includes specific examples, the true scope of the disclosure should not be so limited, as other modifications will become apparent upon study of the drawings, the specification, and the appended claims.

Claims

1. A method for mass production of graphene composite vehicle components, comprising: injecting a first flux into the molten metal contained in the furnace using a first flux injection system; injecting graphene flux into the molten metal using a second flux injection system; stirring and homogenizing the molten metal and the graphene flux in the furnace using a stirrer; transferring the molten metal into a mold having an electromagnetic stirring system; as well as The molten metal is stirred using the electromagnetic stirring system until the molten metal solidifies, wherein the electromagnetic stirring system maintains homogeneity of the molten metal and the graphene flux.

2. The method of claim 1, wherein degassing the first flux and injecting it into the molten metal comprises injecting the first flux into at least one of molten copper or molten aluminum. 3 . The method of claim 1 , wherein degassing and injecting the first flux comprises injecting at least one of nitrogen or argon.

4. The method of claim 1, wherein injecting the graphene flux into the molten metal comprises injecting graphene having a surface treatment.

5. The method of claim 4, wherein the surface treatment comprises at least one of nickel or copper deposited on the graphene flux.

6. The method of claim 1, wherein injecting the graphene flux into the molten metal comprises injecting graphene premixed with at least one of graphene aluminum powder or graphene copper powder.

7. The method of claim 1, wherein stirring and homogenizing the molten metal and the graphene flux comprises using a propeller stirrer.

8. The method of claim 1, wherein transferring the molten metal into a mold having an electromagnetic stirring system comprises injecting the molten metal into a high pressure die casting mold.

9. The method of claim 1, wherein transferring the molten metal into a mold having an electromagnetic stirring system comprises pouring the molten metal into an open mold.

10. The method of claim 1, wherein the cooling temperature of the molten metal is 600°C or less for aluminum and 1000°C or less for copper.

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