Graphene-aluminum composite battery pack cooling plate

Abstract

A battery pack assembly includes a battery pack enclosure, a first cooling plate, a plurality of battery cells, and a plurality of second cooling plates. The first cooling plate is supported by the bottom plate within the battery pack enclosure, and the first cooling plate is formed of a graphene aluminum composite. The plurality of battery cells are supported by a first cooling plate, and the first cooling plate is disposed between the bottom plate of the pack enclosure and the plurality of battery cells. A second cooling plate is disposed between each of the battery cells, and the second cooling plate is formed of a graphene aluminum composite material.

Description

Technical Field

[0001] The present disclosure relates to the field of composite powders, and more particularly, to a cooling plate formed of graphene-aluminum composite powder and systems and methods for producing and using graphene-aluminum powder in additive manufacturing or traditional powder metallurgy processes. Background Art

[0002] Aluminum and aluminum alloy materials are used as thermal conductors in many components (e.g., in electric vehicle battery pack components). Batteries and other vehicle components generate heat within the vehicle battery pack, and this heat must be removed to prevent overheating. In addition, battery pack components are subject to stress, and the structure must remain intact. Also, when aluminum and aluminum alloys are included, over long-term operation, battery pack components are affected by grain growth at elevated operating temperatures (50°C - 100°C).

[0003] While current aluminum and aluminum alloy components achieve their intended purpose, i.e., having thermal conductivity and providing structural strength and stability, there is still a need for vehicle battery pack components and methods and systems for manufacturing components with increased thermal conductivity, structural strength, and material stability. Summary of the Invention

[0004] According to several aspects of the present disclosure, a battery pack component is provided. The battery pack component includes a battery pack enclosure, a first cooling plate, a plurality of battery cells, and a plurality of second cooling plates. The battery pack enclosure includes a bottom plate and a plurality of side walls. The first cooling plate is supported by the bottom plate within the battery pack enclosure and is formed of a graphene-aluminum composite material. The first cooling plate includes a first planar wall and a second planar wall, a first coolant inlet and a first coolant outlet, a first coolant volume, and at least one first coolant flow path. The first coolant inlet and the first coolant outlet are disposed along the edges of the first planar wall and the second planar wall, and the first coolant volume is defined by the first planar wall and the second planar wall. The first coolant flow path is defined by the first coolant volume between the first coolant inlet and the first coolant outlet and extends through the first coolant volume. The plurality of battery cells are supported by the first cooling plate, and the first cooling plate is disposed between the bottom plate of the battery pack enclosure and the plurality of battery cells. The second cooling plates are disposed between each of the battery cells and are formed of a graphene-aluminum composite material. Each of the plurality of second cooling plates includes a third planar wall and a fourth planar wall, a second coolant inlet and a second coolant outlet, a second coolant volume, and a second coolant flow path. The second coolant inlet and the second coolant outlet are disposed along the edges of the third planar wall and the fourth planar wall. The second coolant volume is defined by the third planar wall and the fourth planar wall. The second coolant flow path extends through the second coolant volume between the second coolant inlet and the second coolant outlet.

[0005] According to another aspect of the present disclosure, the battery pack assembly includes a first coolant flow path extending through the first cooling plate in a serpentine configuration.

[0006] According to another aspect of the present disclosure, the battery pack assembly includes battery cells, and the battery cells include at least one prismatic battery cell.

[0007] According to another aspect of the present disclosure, the battery pack assembly includes battery cells oriented perpendicular to the first cooling plate.

[0008] According to another aspect of the present disclosure, the battery pack assembly includes a second cooling plate having a thickness between 0.5 millimeters and 5 millimeters.

[0009] According to another aspect of the present disclosure, the battery pack assembly includes a second cooling plate oriented perpendicular to the first cooling plate.

[0010] According to several aspects of the present disclosure, a method is provided. The method includes a first step of providing an inert environment. The method includes a second step of introducing a first fog into the inert environment, and the first fog is negatively charged atomized aluminum. The method includes a third step of introducing a second fog into the inert environment, and the second fog includes positively charged graphene flakes. The method includes a fourth step of mixing the first fog and the second fog within the inert environment to produce a graphene-aluminum composite powder.

[0011] According to another aspect of the present disclosure, the method includes separating the graphene-aluminum composite powder into multiple grades within the inert environment using a sieve.

[0012] According to another aspect of the present disclosure, the method includes feeding a first grade of the grades into an additive manufacturing device connected to the inert environment.

[0013] According to another aspect of the present disclosure, the method includes a first fog formed from molten aluminum and fed into the inert environment through a high-pressure nozzle.

[0014] According to another aspect of the present disclosure, the method includes a process pressure of the inert environment, and the process pressure includes a vacuum.

[0015] According to another aspect of the present disclosure, the method includes aluminum particles of the graphene-aluminum composite powder, and the aluminum particles are aluminum nanoparticles.

[0016] According to another aspect of the present disclosure, the method includes graphene flakes formed by electrochemical exfoliation.

[0017] According to another aspect of the present disclosure, the method includes using at least one of additive manufacturing or powder metallurgy processes to form a graphene-aluminum composite first cooling plate and a graphene-aluminum composite second cooling plate.

[0018] According to another aspect of the present invention, graphene-aluminum composite powder is formed by the above method.

[0019] According to several aspects of the present disclosure, a system is provided. The system includes a chamber containing an inert environment and a mixing section within the inert environment. The system further includes a first nozzle and a second nozzle. The first nozzle introduces a first mist of negatively charged atomized aluminum into the mixing section of the inert environment. The second nozzle introduces a second mist of positively charged graphene flakes into the mixing section of the inert environment. In addition, the system includes an outlet configured to convey graphene-aluminum composite powder from the inert environment. The system forms graphene-aluminum composite powder by mixing the first mist of negatively charged atomized aluminum and the second mist of positively charged graphene flakes.

[0020] According to another aspect of the present disclosure, the first nozzle of the system is a high-pressure nozzle.

[0021] According to another aspect of the present disclosure, the aluminum particles of the graphene-aluminum composite powder include aluminum nanoparticles.

[0022] According to another aspect of the present disclosure, the system includes at least one screen configured to separate the graphene-aluminum composite powder into multiple grades within the inert environment.

[0023] According to another aspect of the present disclosure, the system includes a forming device configured to use at least one of additive manufacturing or powder metallurgy processes to form at least one of a graphene-aluminum composite first cooling plate or a graphene-aluminum composite second cooling plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way.

[0025] Figure 1 is a perspective view showing a vehicle having a battery pack assembly according to the present disclosure.

[0026] Figure 2 is a perspective view showing a battery pack assembly as Figure 1 shown, the battery pack assembly including a first cooling plate formed of a graphene-aluminum composite material.

[0027] Figure 3 is a perspective view showing a battery pack assembly as Figure 2 shown, the battery pack assembly including a first cooling plate formed of a graphene-aluminum composite material.

[0028] Figure 4A is a perspective view showing a battery pack assembly as Figure 2 and Figure 3 shown, the battery pack assembly including a first cooling plate formed of a graphene-aluminum composite material.

[0029] Figure 4B is an exploded perspective view of a second cooling plate as shown in accordance with the present disclosure. Figure 4A as shown.

[0030] Figure 5 is a schematic diagram of a production system of graphene-aluminum composite powder for forming a first cooling plate and a second cooling plate as shown in accordance with the present disclosure. Figures 2 to 4B as shown.

[0031] Figure 6 is a molecular diagram of graphene-aluminum composite powder for forming a first cooling plate and a second cooling plate as shown in accordance with the present disclosure. Figures 2 to 4B as shown.

[0032] Figure 7 is a flowchart of a method for forming graphene-aluminum composite powder using a system as shown in accordance with the present disclosure. Figure 5 as shown.

[0033] Figure 8 is a schematic diagram of an additive manufacturing apparatus for manufacturing a first cooling plate and a second cooling plate as shown using graphene-aluminum composite powder as shown. Figure 6 as shown Figures 2 to 4B as shown.

[0034] Figure 9 is a schematic diagram of a method for producing a first cooling plate and a second cooling plate as shown using an additive manufacturing apparatus as shown. Figure 8 as shown Figures 2 to 4B as shown. DETAILED DESCRIPTION

[0035] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0036] Referring Figure 1 , a vehicle 10 having a battery pack assembly 12 is shown in accordance with the principles of the present disclosure. The battery pack assembly 12 provides power to the vehicle 10. The battery pack assembly 12 is shown in conjunction with an exemplary vehicle 10, and the vehicle 10 is an electric vehicle or a hybrid vehicle having wheels 14 driven by an electric vehicle motor (not shown). Although the vehicle 10 is shown as a passenger road vehicle, it should be understood that the battery pack assembly 12 can be used with a variety of other types of transportation. For example, the battery pack assembly 12 can be used in marine transportation (such as a ship) or air transportation (such as a drone or a passenger aircraft). Additionally, the battery pack assembly 12 can be used as a stationary power source separate and independent from a transportation vehicle.

[0037] Now referring Figure 2, shows a perspective view of the battery pack assembly 12, and the battery pack assembly generally includes a battery pack enclosure 16, a first cooling plate 18, a plurality of battery cells 20, and a plurality of second cooling plates 22. The battery pack enclosure 16 generally includes a bottom plate 24 and a plurality of side walls 26. The plurality of side walls 26 extend around the perimeter of the bottom plate 24. The bottom plate 24 is a generally flat member and is supported and mounted to the vehicle 10 by mechanical fasteners (not shown, such as bolts passing through holes in the bottom plate 24). Additionally, the battery pack enclosure 16 may include a top cover (not shown) coupled to the plurality of side walls 26.

[0038] Continuing to refer Figure 2 , the first cooling plate 18 is supported by the bottom plate 24 of the battery pack enclosure 16. The first cooling plate 18 regulates the temperature of the battery pack enclosure 16 by removing heat dissipated from the battery or other heat generating devices and transferred to the first cooling plate 18. The first cooling plate 18 forms part of a thermal management system 28 of the battery pack enclosure 16, which generally includes a pump 30, a heat exchanger 32, and a coolant reservoir 34. Without departing from the scope of the present disclosure, the thermal management system 28 may include various other components, including temperature sensors and humidity sensors, valves, and electronic controllers. Generally, the pump 30 is in fluid communication with the coolant reservoir 34 and pumps coolant 36 from the coolant reservoir 34 to the first cooling plate 18. Although the coolant 36 then returns from the first cooling plate 18 and communicates to the heat exchanger 32, which removes heat from the coolant 36 using, for example, a liquid-air heat exchanger with a fan, other types of heat exchangers may also be employed. Then, the coolant 36 returns to the coolant reservoir 34.

[0039] Figure 3 shows an exploded perspective view of the first cooling plate 18. The first cooling plate 18 is formed of a graphene-aluminum composite material and includes a first planar wall 38 and a second planar wall 40, a first coolant inlet 42, a first coolant outlet 44, a first coolant volume 46, and at least one first coolant flow path 48. The first planar wall 38 and the second planar wall 40 are coupled together and generally have a rectangular or square shape defining four edges 50a, 50b, 50c, 50d of the first cooling plate 18. The first planar wall 38 and the second planar wall 40 are close together and conduct heat from the batteries and other heat generating devices within the battery pack assembly 12.

[0040] The first coolant inlet 42 and the first coolant outlet 44 are arranged along the edges 50a, 50b, 50c, 50d of the first cooling plate 18. As Figure 2As shown, a first coolant inlet 42 and a first coolant outlet 44 are in fluid communication with a pump 30, a heat exchanger 32, and a coolant reservoir 34. The first coolant inlet 42 is configured to receive coolant 36 from the thermal management system 28, and the first coolant outlet 44 is configured to return the coolant 36 to the thermal management system 28. It should be understood that the first cooling plate 18 may include a plurality of first coolant inlets 42 and / or first coolant outlets 44.

[0041] Continuing to refer Figure 3 , a first coolant volume 46 is defined by a first planar wall 38 and a second planar wall 40. The first coolant volume 46 is configured to contain coolant 36 that provides a convective cooling effect to the first planar wall 38 and the second planar wall 40. A first coolant flow path 48 is defined by the first coolant volume 46 between the first coolant inlet 42 and the first coolant outlet 44 and extends through the first coolant volume 46. As Figure 3 shown, the first coolant flow path 48 may be a serpentine configuration. However, it should be understood that the first coolant flow path 48 may be other configurations, such as a linear configuration. Additionally, the first coolant volume 46 may include a plurality of first coolant flow paths 48, e.g., as Figure 3 shown, three first coolant paths 48a, 48b, 48c.

[0042] Referring again Figure 2 , a plurality of battery cells 20 are supported by the first cooling plate 18. The first cooling plate 18 provides cooling to the plurality of battery cells 20 by heat transfer. The battery cells 20 are preferably prismatic battery cells, and the chemistry of the battery cells is enclosed in a rigid rectangular housing. The rectangular housing allows for efficient stacking of the battery cells 20. However, it should be understood that any type of battery cell 20 may be employed as long as the battery cell 20 is compatible with the battery pack assembly 12, e.g., a cylindrical lithium-ion battery cell or a pouch cell. Additionally, the plurality of battery cells 20 are shown oriented perpendicular to the first cooling plate 18. However, it should be understood that the plurality of battery cells 20 may be arranged in other orientations as long as the battery cells 20 are supported by the first cooling plate 18.

[0043] Figure 4A A perspective view of a plurality of second cooling plates 22 is shown. The second cooling plates 22 are disposed between each of the plurality of battery cells 20. In as Figure 4AIn the example shown, the second cooling plate 22 is disposed on the first cooling plate 18 and is in fluid communication with the first cooling plate 18. For illustrative purposes only, a portion of the second cooling plate 22 is not shown between the battery cells 20. The second cooling plate 22 is configured to provide cooling to the battery cells 20 by heat transfer through the circulation of coolant 36 within it. Each second cooling plate 22 is formed of a graphene-aluminum composite material and may have different thicknesses (e.g., 0.5 mm, 1 mm, 2 mm, 5 mm, etc.). In the example as Figure 4A shown, each second cooling plate 22 is oriented perpendicular to the first cooling plate 18. However, it should be understood that the second cooling plate 22 may be configured in other orientations as long as the second cooling plate 22 is disposed between the battery cells 20. As Figure 4A and Figure 4B shown, each second cooling plate 22 includes a third planar wall 52 and a fourth planar wall 54, a second coolant inlet 56 and a second coolant outlet 58, a second coolant volume 60, and at least one second coolant flow path 62.

[0044] Continuing to refer to Figure 4A and Figure 4B , the third planar wall 52 and the fourth planar wall 54 are coupled together and generally have a rectangular or square shape. The third planar wall 52 and the fourth planar wall 54 define four edges 64a, 64b, 64c, 64d of the second cooling plate 22. The third planar wall 52 and the fourth planar wall 54 are adjacent to and close to the battery pack cells 20 and other heat generating devices within the battery pack assembly 12 to conduct heat from the battery pack cells 20 and other heat generating devices.

[0045] The second coolant inlet 56 and the second coolant outlet 58 are disposed along the edges 64a, 64b, 64c, 64d of the second cooling plate 22. As Figure 4A shown, the second coolant inlet 56 and the second coolant outlet 58 are in fluid communication with the pump 30, the heat exchanger 32, and / or the coolant reservoir 34 through the first cooling plate 18. It should be understood that the second cooling plate 22 may be in fluid communication with the pump 30, the heat exchanger 32, and / or the coolant reservoir 34 in other ways (e.g., the second cooling plate 22 may be directly connected to the pump 30, the heat exchanger 32, and / or the coolant reservoir 34 through hoses, pipes, etc.). The second coolant inlet 56 is configured to receive the coolant 36 from the first cooling plate 18, and the second coolant outlet 58 is configured to return the coolant 36 to the first cooling plate 18, the pump 30, the heat exchanger 32, and / or the coolant reservoir 34.

[0046] Still referring to Figure 4A and 4B, the second coolant volume 60 is defined by the third planar wall 52 and the fourth planar wall 54. The second coolant volume is configured to contain a coolant 36 that provides a convective cooling effect to the second cooling plate 22. The second coolant flow path 62 is defined by the second coolant volume 60 between the second coolant inlet 56 and the second coolant outlet 58 and extends through the second coolant volume 60. As Figure 4A shown, the second coolant flow path 62 can be a generally segmented linear configuration having a series of continuously arranged segments 62a, 62b, 62c. It should be understood that the second coolant flow path 62 can be other configurations (such as a serpentine configuration). Additionally, the second coolant volume 60 can include multiple second coolant flow paths 62, for example, as Figure 4A shown, four second coolant paths. The first cooling plate 18 and the plurality of second cooling plates 22 can use this system and method and are formed using the graphene-aluminum composite powder discussed in more detail below.

[0047] Figure 5 An exemplary system 100 for producing graphene-aluminum composite powder 101 is shown. The system includes a chamber 102, an aluminum feedstock 104, a graphene feedstock (not shown), a mixing section 105, a separation section 106, and a graphene-aluminum composite powder outlet 108. The chamber 102 includes an inert environment therein that can be adjusted using a vacuum source 110, an inert gas inlet 112, an inert gas outlet 114, and a temperature regulating device (not shown).

[0048] The vacuum source 110 is configured to evacuate air from the inert environment during startup. The vacuum source 110 or another vacuum source can be further configured separately or in combination with other devices to maintain the inert environment at a desired process pressure.

[0049] An inert gas flows through the system 100 to inhibit oxidation of the powder and its particles. The inert gas enters the chamber 102 via the inert gas inlet 112 and exits the chamber 102 through the inert gas outlet 114. The flow of the inert gas can also be configured to affect or create a desired gas flow pattern within the system 100. For example, the inert gas inlet 112 can be located below the separation section 106, while the inert gas outlet 114 can be located above the separation section 106 such that the flow of the inert gas promotes agitation of the graphene-aluminum composite powder 101 to assist in separating the graphene-aluminum composite powder 101 according to size (e.g., by promoting fluidization of the graphene-aluminum composite powder 101).

[0050] The temperature regulating device is configured to heat and / or cool an inert environment to a desired temperature profile. The temperature profile can be a uniform temperature, multiple zones with different temperatures, a temperature gradient, a combination thereof, etc. In some aspects, the temperature profile is generated by controlling the temperature of the feedstock, the spacing of components, and the insulation or thermal conductivity of the system chamber 102.

[0051] Aluminum and graphene are fed into the mixing section 105 of the system 100 through respective nozzles 116A, 116B. The aluminum and graphene carry opposite charges. Advantageously, although not bound by theory, it is believed that providing the feed in the form of oppositely charged particles enhances the contact between the aluminum particles and the graphene flakes, as well as the packing of the resulting graphene-aluminum composite powder 101. In one example, the nozzles 116A, 116B can include one or more high-pressure nozzles. Additionally or alternatively, the nozzles 116A, 116B can include one or more electrospray nozzles.

[0052] Furthermore, the amount of charge imparted to the particles is selected to reduce voids in the resulting powder and the parts formed therefrom. For example, only a portion of the aluminum particles can be charged such that the charged particles are attracted to the graphene flakes, while the uncharged particles reduce the repulsive forces that may leave voids in the resulting powder or during the additive manufacturing process. Any residual charge can be removed by grounding after mixing (e.g., by grounding the sieves 124A, 124B).

[0053] Continuing to refer Figure 5 , the first nozzle 116A is coupled to the aluminum feedstock 104 (e.g., deoxidized aluminum melt 118). The first nozzle 116A is configured to produce a negatively charged atomized aluminum mist 120 having a desired particle size distribution. In an example, the aluminum particles within the atomized aluminum mist 120 can be nanoparticles. In some cases, the diameter of the aluminum particles is approximately the lateral flake size of the graphene particles, which provides an enhanced aluminum-aluminum interface. In other cases, the diameter of the aluminum particles is one order of magnitude smaller than the lateral flake size of the graphene particles, which provides enhanced aluminum-aluminum and graphene-aluminum interfaces. In additional cases, the diameter of the aluminum particles is two orders of magnitude smaller than the lateral flake size of the graphene particles, which provides an enhanced graphene-aluminum interface.

[0054] The second nozzle 116B is coupled to the graphene feedstock. The second nozzle 116B is configured to produce a positively charged graphene mist 122. The graphene feedstock includes pristine graphene flakes in a solvent. The size of the graphene flakes is designed to provide the mechanical, electrical conductivity, and / or thermal conductivity properties required for the resulting graphene-aluminum composite part. The graphene flakes can be single-layer graphene flakes and / or few-layer graphene flakes. In some cases, the graphene flakes are formed by an electrochemical exfoliation technique. In one embodiment, the average lateral diameter of the graphene flakes is between 10 nm and 10 μm.

[0055] A solvent is selected to avoid negative interactions with the aluminum mist 120. For example, a solvent is selected to avoid alumina particles, flocculate the aluminum particles, or produce an undesired shape of the aluminum particles. A solvent that does not exist in the resulting powder under the process conditions is also selected. The solvent can be or include a polar solvent (e.g., an alcohol such as methanol or ethanol) and / or a non-polar solvent (e.g., a medium-chain to long-chain hydrocarbon such as gasoline or kerosene).

[0056] The aluminum mist 120 and the graphene mist 122 are combined in the mixing section 105 of the inert environment. The mixing section 105 is designed to produce a uniform mixture of the two mists. For example, the nozzles 116A, 116B can be distributed around the mixing section 105 such that the turbulence from the ejected mists provides a uniform mixing of the aluminum particles and the graphene flakes. Additionally or alternatively, the flow of the inert gas can be controlled to enhance the mixing of the mists. For example, the mixing can be enhanced by selecting the positions of the inert gas inlet 112 and the inert gas outlet 114, the flow rate of the inert gas, the positioning of the flow control features (e.g., baffles, shapers, and turbulators), combinations thereof, etc.

[0057] After the two mists are uniformly mixed, the graphene-aluminum composite powder 101 settles into the separation section 106 of the inert environment. The separation section 106 can include, for example, a plurality of sieves 124A, 124B. The sieves 124A, 124B are arranged such that the graphene-aluminum composite powder 101 is filtered by a first sieve 124A having a larger pore size than the subsequent sieve 124B, such that the graphene-aluminum composite powder 101 is separated into a plurality of grades 126A, 126B, 126C having known and distinct particle size distributions. Each of the plurality of grades 126A, 126B, 126C can be selected for their respective uses. For example, one of the grades 126C can be selected for an additive manufacturing process, another of the grades 126B can be further processed for other uses, and another of the grades 126A can be processed to remove contaminants and recycled into the aluminum melt 118.

[0058] In some instances, the graphene in the graphene-aluminum composite powder 101 and / or a particular one or more of grades 126A, 126B, 126C is between 1 wt.% and 40 wt.%. In a further example, the graphene in the graphene-aluminum composite powder 101 and / or a particular one or more of grades 126A, 126B, 126C is between 0.001 vol.% (volume fraction) and 30 vol.%. In a further example, the graphene in the graphene-aluminum composite powder 101 and / or a particular one or more of grades 126A, 126B, 126C is between 10 vol.% and 20 vol.%. Advantageously, optimized tensile strength and electrical properties can be obtained using composite graphene-aluminum composite powders having graphene flakes with an average lateral flake diameter of 2 μm and a loading of 10 vol.%, an average lateral flake diameter of 5 μm and a loading of 15 vol.%, or an average lateral flake diameter of 7 μm and a loading of 20 vol.%. Advantageously, reducing the average lateral flake diameter generally reduces the amount of graphene required in the resulting powder.

[0059] In some cases, the system 100 is coupled to an additive manufacturing device, e.g., the device described in Figure 8 reference. The graphene-aluminum composite powder outlet 108 can be coupled to the device such that they include a shared inert environment for directly transferring one or more desired grades 126A, 126B, 126C of the powder from the system to the additive manufacturing device. Additionally or alternatively, grades 126A, 126B, 126C can be delivered to a container within the inert environment, which can then be sealed, removed from the inert environment, and moved to the additive manufacturing device and opened / accessed for use within the inert environment of the additive manufacturing equipment.

[0060] Figure 6 An exemplary graphene-aluminum composite powder 101 produced by the system 100 is shown. It can be seen that the graphene flakes 202 are distributed throughout the aluminum particles 204. Electrostatic or imparted charge can enhance the contact between the aluminum particles 204 and the plane of the graphene flakes 202, which reduces or eliminates the lattice gaps in the powder that would otherwise cause the aluminum particles 204 to contact only the edges of one or more graphene flakes 202.

[0061] Avoiding lattice gaps and optimizing the contact between aluminum particles 204 and graphene flakes 202 enhances the electrical conductivity, thermal conductivity, stability, and mechanical properties of parts (e.g., the first cooling plate 18, the second cooling plate 22) made from the graphene-aluminum composite powder 101. Charges can be selected to balance the different electronic properties of the planar and edge portions of the graphene flakes 202, thereby further optimizing the powder packing and other physical properties, as well as the properties of the parts formed from the powder. Advantageously, the mixing of charged particles also increases the graphene loading of the graphene-aluminum composite powder 101. For example, the graphene-aluminum composite powder formed by mixing charged particles may result in a graphene loading between 30 vol.% and 40 vol.%, which is higher than the expected loading between 20 vol.% and 25 vol.% for mixing the same uncharged particles.

[0062] Figure 7 A method 300 for producing the graphene-aluminum composite powder 101 as shown Figure 6 is shown. At block 302, the method includes providing an inert environment. At blocks 304 and 306, a first mist (such as negatively charged atomized aluminum particles 204) and a second mist (such as positively charged graphene flakes 202 in a solvent) are introduced into the environment. The first mist and the second mist are provided with opposite charges such that when mixed, the aluminum particles 204 in the first mist are attracted to the flat surfaces on the graphene flakes 202 in the second mist. The method 300 further includes mixing the first mist and the second mist at block 308 to produce the graphene-aluminum composite powder 101. The method 300 may also include an optional step 310 of separating or filtering the produced powder into multiple levels 126A, 126B, 126C having a known particle size distribution and known area fractions or volume fractions of the graphene flakes 202 and aluminum particles 204. The area fraction or volume fraction of each of the multiple levels is expected to be different. The method 300 may also include an optional step 312 of feeding the first level of the multiple levels 126A, 126B, 126C into an additive manufacturing device coupled to the inert environment.

[0063] Figure 8 An exemplary additive manufacturing device 400 (such as a forming device) is shown. The additive manufacturing device 400 is configured to form parts (e.g., the first cooling plate 18 and / or multiple second cooling plates 22) using the graphene-aluminum composite powder 101 through a layer-by-layer process. The additive manufacturing device 400 includes a sintering device 402, a chamber 404, a powder supplier 406, and a powder bed 408.

[0064] The sintering device 402 is configured to selectively form bonding portions within the graphene-aluminum composite powder 101 when the graphene-aluminum composite powder 101 is exposed to the sintering device 402. The selective formation of the bonding portions results in the resulting graphene-aluminum composite part 410 (e.g., the first cooling plate 18 and / or the plurality of second cooling plates 22), such that enhanced contact between the graphene flakes 202 and the aluminum particles 204 of the graphene-aluminum composite powder 101 is maintained in the resulting graphene-aluminum composite part 410.

[0065] In the illustrated figure, the sintering device 402 is an electron gun 412 that emits an electron beam 414. The electron beam 414 is shaped and aimed at a focal point corresponding to the upper surface 416 of the powder bed 408 such that the electron beam 414 melts a volume of the graphene-aluminum composite powder 101 to produce a layer of the resulting graphene-aluminum composite part 410 (e.g., the first cooling plate 18, the second cooling plate 22).

[0066] The chamber 404 includes an inert environment. The inert environment can employ the same inert gas as the system or can employ a different inert gas. Additionally or alternatively, the inert environment can be an ultra-low pressure environment. Further, the chamber 404 includes a powder supplier 406 and a powder bed 408 within the inert environment.

[0067] The powder supplier 406 is configured to maintain the graphene-aluminum composite powder 101 in the inert environment and deliver it to the additive manufacturing device 400 for use in the powder bed 408. Although the illustrated powder supplier 406 is a container within the inert environment of the chamber 404, it is contemplated that the container or other delivery mechanism can be connected external to the chamber 404 without exposing the graphene-aluminum composite powder 101 to the inert environment.

[0068] The powder bed 408 includes a platform 418 that can be moved relative to the sintering device 402. In the illustrated embodiment, the platform 418 is configured to move in three dimensions using a Cartesian coordinate system. It should be understood that other platform systems can be used. The powder bed 408 is configured to contain a quantity of the graphene-aluminum composite powder 101 that moves therewith.

[0069] Figure 9FIG. 0 shows a flow chart of a process 500 for producing a graphene-aluminum composite part 410 (e.g., a first cooling plate 18, a second cooling plate 22) from a graphene-aluminum composite powder 101. The process 500 begins at block 502 where an amount of the graphene-aluminum composite powder 101 is fed onto a substrate. Next, at block 504, an amount of the graphene-aluminum composite powder 101 is prepared for sintering. The preparation steps can include, for example, drying an amount of the graphene-aluminum composite powder 101, bringing an amount of the graphene-aluminum composite powder 101 to a predetermined temperature or temperature profile, and / or treating the surface 416 of the graphene-aluminum composite powder 101 to enhance sintering or exposure to a sintering apparatus 402. The surface treatment can include, for example, chemical treatment or mechanical treatment.

[0070] Block 506 of the process 500 includes exposing the surface 416 of the powder bed 408 to the sintering apparatus 402 while translating the powder bed 408. The powder bed 408 is translated in one or more dimensions and at one or more speeds such that the portion of the graphene-aluminum composite powder 101 exposed to the sintering apparatus 402 forms one or more features of a cross-sectional layer of the resulting part.

[0071] After forming the desired features of the layer, block 508 of the process 500 includes determining whether the part is complete. If it is determined that the part is not complete, the platform 418 is moved such that an additional layer of the resulting part can be formed and attached to the previous layer. Then, the process 500 forms one or more features of the corresponding cross-sectional layer by feeding another amount of the graphene-aluminum composite powder 101 onto the substrate on top of the previous layer, preparing the graphene-aluminum composite powder 101 for sintering, and exposing the corresponding layer to the sintering apparatus 402 while translating the powder bed 408. This process is repeated until all the desired features of all the desired layers of the part are formed.

[0072] Optionally, block 510 of the process 500 can include steps for further processing or treating the formed part to produce a finished graphene-aluminum composite object having desired mechanical, thermal, and / or electronic properties. For example, hot pressing or annealing can be employed to optimize interlayer adhesion and / or optimize grain boundaries and other material properties of the formed part. Additionally or alternatively, the substrate can be a disposable substrate that is removed from the formed part by mechanical processes, chemical treatment, thermal or light exposure, combinations thereof, etc.

[0073] Although the present disclosure discusses additive manufacturing using the graphene-aluminum composite powder 101, it is contemplated that other powder metallurgy forming apparatuses and techniques can be used to produce graphene-aluminum composite parts (e.g., a first cooling plate 18, a second cooling plate 22) using the graphene-aluminum composite powder 101.

[0074] Compared with the cooling plates of the prior art, the present disclosure has many advantages and benefits. For example, compared with the cooling plates formed only of aluminum or aluminum alloy, the first cooling plate 18 and the plurality of second cooling plates 22 formed using the graphene-aluminum composite powder provide higher thermal conductivity. The graphene-aluminum cooling plate promotes efficient heat dissipation, is beneficial to the battery life of electric vehicles, and reduces the overall weight of the vehicle battery. In addition, using graphene-aluminum instead of traditional aluminum or aluminum alloy to form the cooling plate increases the strength of the cooling plate and prevents grain growth of the cooling plate due to long-term operation at the working temperature (such as 50°C - 100°C).

[0075] This description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses. The broad teachings of the present disclosure can be implemented in many forms. Thus, while the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited because other modifications will become apparent after studying the drawings, the specification, and the appended claims.

Claims

1. A battery pack assembly, comprising: A battery pack enclosure, comprising a bottom plate and a plurality of side walls; A first cooling plate supported by a bottom plate within the battery pack enclosure, wherein the first cooling plate is formed of a graphene aluminum composite material, and wherein the first cooling plate comprises: a first planar wall and a second planar wall; a first coolant inlet and a first coolant outlet disposed along edges of the first planar wall and the second planar wall; a first coolant volume defined by the first planar wall and the second planar wall; and at least one first coolant flow path defined by the first coolant volume between the first coolant inlet and the first coolant outlet and extending through the first coolant volume; a plurality of battery cells supported by the first cooling plate, wherein the first cooling plate is disposed between a bottom plate of the battery pack enclosure and the plurality of battery cells; and a plurality of second cooling plates, wherein each of the plurality of second cooling plates is disposed between each of the plurality of battery cells, wherein each of the plurality of second cooling plates is formed of a graphene aluminum composite material, and wherein each of the plurality of second cooling plates comprises: a third planar wall and a fourth planar wall; a second coolant inlet and a second coolant outlet disposed along edges of the third planar wall and the fourth planar wall; a second coolant volume defined by the third planar wall and the fourth planar wall; and At least one second coolant flow path extends through the second coolant volume between the second coolant inlet and the second coolant outlet. 2 . The battery pack assembly of claim 1 , wherein the first coolant flow path extends through the first cooling plate in a serpentine configuration. 3 . The battery pack assembly of claim 1 , wherein the plurality of battery cells includes at least one prismatic battery cell. 4 . The battery pack assembly of claim 1 , wherein each of the plurality of battery cells is oriented perpendicular to the first cooling plate. 5 . The battery pack assembly of claim 1 , wherein a thickness of each of the plurality of second cooling plates is between 0.5 mm and 5 mm. 6 . The battery pack assembly of claim 1 , wherein each of the plurality of second cooling plates is oriented perpendicular to the first cooling plate.

7. A method comprising: Provide an inert environment; introducing a first mist into the inert environment, the first mist being negatively charged atomized aluminum; introducing a second mist into the inert environment, the second mist comprising positively charged graphene flakes; and The first mist and the second mist are mixed in the inert environment to generate graphene-aluminum composite powder.

8. The method according to claim 7, further comprising: The graphene-aluminum composite powder is separated into multiple grades using at least one sieve in the inert environment.

9. The method according to claim 8, further comprising: A first level of the plurality of levels is fed into an additive manufacturing apparatus coupled to the inert environment.

10. The method of claim 7, wherein the first mist is formed from aluminum melt fed into the inert environment through a high pressure nozzle.

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