Heat Conduction Plate

Abstract

A thermally conductive plate including a vapor chamber is manufactured by disposing a vapor core and a wicking layer within a cavity defined between spaced apart walls of a casing, injecting a working fluid into the cavity, and applying a vacuum to the cavity. After applying the vacuum to the cavity, the periphery of the spaced apart walls are cold welded together to seal the working fluid, the vapor core and the wicking layer within the cavity.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Patent Application No. 63 / 290,752, filed December 17, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates generally to heat transfer devices, and more particularly, to heat pipes operable to transfer heat between two components. [Background technology]

[0003] Electric vehicles and other types of electric devices may be powered by one or more electric batteries. Each battery typically includes multiple cells operatively connected to one another. Such batteries generate heat when power is drawn from the battery. In some cases, operating the battery when its temperature exceeds a maximum temperature threshold (which may be caused by high ambient temperatures) may hinder the performance of the battery, and in some cases, damage the battery. Additionally, battery performance may decrease when the battery is operated at a temperature below a minimum temperature threshold. Although attempts have been made to better regulate the temperature of batteries, improvements are still needed. Summary of the Invention

[0004] In one aspect, a method of manufacturing a thermally conductive plate having a vapor chamber is provided, the method including obtaining a vapor core and a wicking layer, disposing the vapor core and the wicking layer within a cavity defined between spaced-apart walls of a casing, injecting a working fluid within the cavity, applying a vacuum to the cavity, and cold welding a periphery of the spaced-apart walls together to seal the working fluid and the vapor core and wicking layer within the cavity after applying the vacuum to the cavity.

[0005] The methods described herein, as defined above, may further comprise, in whole or in part, and in any combination, one or more of the following steps / features:

[0006] In some embodiments, applying a vacuum to the cavity includes disposing the vapor core, the wicking layer, and the casing in a vacuum chamber and applying a vacuum to the vacuum chamber.

[0007] In some embodiments, applying a vacuum to the cavity includes disposing the vapor core, the wicking layer, and the casing inside a vacuum chamber under vacuum prior to injecting the working fluid inside the cavity.

[0008] In some embodiments, the method includes obtaining a second wicking layer and enclosing a vapor core between the wicking layer and the second wicking layer.

[0009] In some embodiments, disposing the vapor core and wicking layer within the cavity includes disposing the vapor core and wicking layer within a cavity defined by spaced apart walls that are claddings of two different materials.

[0010] In some embodiments, disposing the vapor core and wicking layer within a cavity defined by spaced apart walls includes disposing the vapor core and wicking layer within a cavity defined by spaced apart walls, the cavity being an aluminum copper clad casing or a stainless steel copper clad casing.

[0011] In some embodiments, injecting the working fluid includes injecting water above a recessed portion defined by the first casing portion of the casing.

[0012] In some embodiments, the method includes disposing a vapor core and a wicking layer over the first casing portion, and injecting the working fluid includes injecting the working fluid into the wicking layer.

[0013] In some embodiments, obtaining the vapor core and wicking layer includes obtaining a wicking layer that is a layer of metal foam, sintered metal powder, and / or one or more layers of metal mesh.

[0014] In some embodiments, the method includes bonding a wicking layer to one of the spaced apart walls.

[0015] In some embodiments, the method includes securing a wicking layer to one of the spaced apart walls to obtain a first subassembly, securing a second wicking layer to the other of the spaced apart walls to obtain a second subassembly, and enclosing a vapor core between the first subassembly and the second subassembly.

[0016] In some embodiments, the method includes bending the vapor core, the wicking layer, and the casing into a shape defining an elbow prior to cold welding.

[0017] In some embodiments, the method includes bending the vapor core, the wicking layer, and the casing into a shape defining an elbow after cold welding.

[0018] In some embodiments, obtaining a vapor core includes obtaining a vapor core that is a hydrophobic porous layer, a nylon mesh, a polymer mesh, and / or a pillar.

[0019] In some embodiments, the vapor core includes a plurality of vapor core strips and the wicking layer includes a plurality of wicking layer strips, and the method includes disposing the vapor core strips and the wicking layer strips so as to be spaced apart from one another within the cavity.

[0020] In another aspect, a thermally conductive plate having a vapor chamber is provided, the thermally conductive plate comprising: a first casing and a second casing defining a cavity therebetween; a core assembly having a wicking layer adjacent an inside of the first casing and a vapor core, the wicking layer and the vapor core being received within the cavity; and a working fluid within the cavity, wherein a first peripheral flange of the first casing is sealingly joined to a second peripheral flange of the second casing along a complete continuous perimeter of the first casing and the second casing, the first casing being connected to the second casing via the first peripheral flange and the second peripheral flange.

[0021] The thermally conductive plate described herein as defined above may further comprise, in whole or in part, and in any combination, one or more of the following features:

[0022] In some embodiments, the first casing and the second casing include claddings of two different materials.

[0023] In some embodiments, the two different materials include aluminum and copper, and the inside of the first casing and the inside of the second casing are defined by copper.

[0024] In some embodiments, the melting point of one of the two different materials is less than the hot welding temperature of the other of the two different materials.

[0025] In some embodiments, the wicking layer comprises a layer of metal foam, sintered metal powder, and / or one or more layers of metal mesh.

[0026] In some embodiments, the vapor core comprises a hydrophobic porous layer, a nylon mesh, a polymer mesh, and / or pillars.

[0027] In some embodiments, the melting point of the steam core is less than a hot welding temperature of the first casing.

[0028] In some embodiments, a wicking layer is bonded to a first casing, a second wicking layer is bonded to a second casing, and a vapor core is disposed between the wicking layer and the second wicking layer.

[0029] In some embodiments, the wicking layer includes a plurality of wicking layer strips and the vapor core includes a plurality of vapor core strips, the wicking layer strips and the vapor core strips being spaced apart from one another within the cavity.

[0030] In yet another aspect, a power module for powering an electrical device is provided, the power module comprising: a housing having an internal volume; a battery located within the internal volume of the housing; a heat sink; a thermally conductive plate, the battery being in thermal exchange relationship with the heat sink via the thermally conductive plate; a first casing and a second casing defining a cavity therebetween; a core assembly having a wicking layer adjacent an inside of the first casing and a vapor core, the wicking layer and the vapor core being received within the cavity; and a working fluid within the cavity; wherein a first peripheral flange of the first casing is sealingly coupled to a second peripheral flange of the second casing along a complete continuous perimeter of the first casing and the second casing; and wherein the first casing is connected to the second casing via the first peripheral flange and the second peripheral flange.

[0031] The power modules described herein, as defined above, may further comprise one or more of the following features, in whole or in part, and in any combination.

[0032] In some embodiments, a wicking layer is bonded to a first casing, a second wicking layer is bonded to a second casing, and a vapor core is disposed between the wicking layer and the second wicking layer.

[0033] In some embodiments, the wicking layer includes a plurality of wicking layer strips and the vapor core includes a plurality of vapor core strips, the wicking layer strips and the vapor core strips being spaced apart from one another within the cavity.

[0034] Many further features and combinations of the present improvements will be apparent to those of skill in the art upon reading this disclosure. [Brief description of the drawings]

[0035] [Figure 1] 1 is a schematic diagram of a vehicle battery cooling system. [Diagram 2] 2 is a three-dimensional partial cutaway view of a thermally conductive plate according to one embodiment for use with the battery cooling system of FIG. 1. [Diagram 3] FIG. 3 is an enlarged view of a portion of FIG. [Figure 4] 3 is a schematic cross-sectional view illustrating the layered structure of the heat conduction plate of FIG. 2. [Diagram 5] 3 is a schematic cross-sectional view of the heat transfer plate of FIG. 2 illustrating the process of heat exchange. [Figure 6A] 3A to 3C are schematic side views illustrating a process for manufacturing the heat conductive plate of FIG. 2. [Figure 6B] 3A to 3C are schematic side views illustrating a process for manufacturing the heat conductive plate of FIG. 2. [Figure 6C] 3A to 3C are schematic side views illustrating a process for manufacturing the heat conductive plate of FIG. 2. [Figure 7] A schematic cross-sectional view illustrating a layered structure according to another embodiment. [Figure 8] FIG. 13 is a top view of a thermally conductive plate according to another embodiment. [Figure 9] 9 is a cross-sectional view of the thermally conductive plate of FIG. 8 taken along line AA of FIG. 8. [Figure 10] 1 is a flow chart illustrating a method for manufacturing a thermally conductive plate. [Figure 11A] FIG. 13 is a side view of a thermally conductive plate according to an alternative embodiment. [Figure 11B] FIG. 13 is a side view of a thermally conductive plate according to an alternative embodiment. [Figure 11C] FIG. 13 is a side view of a thermally conductive plate according to an alternative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] 1, a power module that may be used within a vehicle 10 is shown and includes a cooling system 20 for cooling one or more electric batteries 12 (only one is shown in FIG. 1) of the vehicle 10. The cooling system 20 includes a thermally conductive plate 30 in heat exchange relationship with the battery 12 for absorbing heat from the battery or for transferring heat to the battery 12. In this embodiment, the thermally conductive plate 30 is in thermal contact with the battery 12 such that heat may be transferred between the battery 12 and the thermally conductive plate 30 by conduction.

[0037] In one particular embodiment, the thermally conductive plate 30 may be selectively moved between a heat transfer position and a heat insulating position, as depicted by solid and dashed lines in FIG. 1, respectively. Although not shown, an actuator may be located between the thermally conductive plate 30 and the battery 12 to provide for the movement of the thermally conductive plate 30 between the heat transfer position and the heat insulating position. However, it should be understood that the cooling system 20 and the thermally conductive plate 30 described herein may be used in other applications, including thermal management of any type of battery and / or battery pack, which may not include, for example, a switchable or movable portion of the thermally conductive plate 30.

[0038] The heat sink 22 of the cooling system 20 may be used to draw heat from the battery 12 via the thermally conductive plate 30. The heat sink 22 may be any suitable device operable for heat exchange. The heat sink 22 may include, for example, fins, conduits for flowing coolant, etc. The heat sink 22 may be an alternatively configured heat source for providing heat to the battery 12 via the thermally conductive plate 30.

[0039] 2-4, the heat transfer plate 30 will be described in more detail. In the depicted embodiment, the heat transfer plate 30 includes a first section 31, which may be referred to as a condenser section, and a second section 32, which may be referred to as an evaporator section, generally intersecting the first section 31 such that the heat transfer plate 30 has an L-shape in the depicted embodiment. It will be understood that other suitable shapes may alternatively be used, as described below with reference to FIGS. 11A-11C. Shapes are contemplated in which the first section 31 and the second section 32 are articulated via an elbow. In certain embodiments, the elbow may define an interior angle of approximately 90 degrees (e.g., 90 degrees ±10%) between the first and second sections of the heat transfer plate, although the angle may differ (e.g., greater or less) than 90 degrees ±10%. The first section 31 may be pivotable relative to the second section 32 about an axis defined by an intersection between the first section 31 and the second section 32. The first section 31 may be moved between a heat transferring position and a heat insulating position as shown in FIG. 1. The second section 32 may contact the battery 12 when placed in abutting relationship with the battery as shown in FIG. 1. Although the thermally conductive plate 30 depicted in FIG. 2 has a bend in the plate to form the L-shape of the thermally conductive plate 30, it should be understood that the thermally conductive plate 30 described herein may also be a flat (i.e., non-bent) plate.

[0040] 3 and 4, the heat transfer plate 30 has a layered structure 100. The layered structure 100 includes an outer envelope or casing consisting of a first casing portion 101 and a second casing portion 102 (hereinafter simply referred to as the first casing 101 and the second casing 102). A cavity 103 is defined between the first casing 101 and the second casing 102. The cavity 103 may alternatively be referred to as a vapor chamber or vapor core. The first casing 101 is connected to the second casing 102 along the periphery 33 of the heat transfer plate 30, as described in more detail below. More specifically, a first peripheral flange 101A of the first casing 101 is adjacent to and sealingly secured to a second peripheral flange 102A of the second casing 102 along the complete continuous periphery of the first casing 101 and the second casing 102. The first casing 101 is connected to the second casing 102 via a first peripheral flange 101A and a second peripheral flange 102A. Further details regarding how the first casing 101 and the second casing 102 are connected in this manner are provided below.

[0041] In the context of the present disclosure, the expression "sealed and fixed" means that the first peripheral flange 101A and the second peripheral flange 102A are fixed to each other in a permanent manner. In other words, the bond between the first peripheral flange 101A and the second peripheral flange 102A is permanent and forms a seal such that the pressure inside the cavity 103 remains constant regardless of pressure fluctuations in the environment outside the cavity 103. This permanent bond may be created by making the first peripheral flange 101A and the second peripheral flange 102A into a unitary distinct part, as will be discussed below.

[0042] 3 and 4, in the illustrated embodiment, the cavity 103 is defined by the first casing 101 having a first wall 101B offset from the first peripheral flange 101A to define a recessed portion. The second casing 102 has a second wall 102B (FIG. 4) that may be offset from the second peripheral flange 102A. When the first casing 101 is fixed to the second casing 102 via the first peripheral flange 101A and the second peripheral flange 102A of the first casing 101 and the second casing 102, respectively, the first wall 101B and the second wall 102B (see, for example, FIG. 4) are spaced apart from each other. Thus, the cavity 103 is defined between the first wall 101B and the second wall 102B. It will be appreciated that only one of the first wall 101B and the second wall 102B may be offset from its corresponding first and second peripheral flanges 101A, 102A to create a space between the first wall 101B and the second wall 102B. In some cases, both the first wall 101B and the second wall 102B are offset from the first and second peripheral flanges 101A, 102A.

[0043] In an alternative embodiment, a spacer may be sandwiched between the first wall 101B and the second wall 102B to create a space between the first wall 101B and the second wall 102B forming the cavity 103. However, one or more spacers may only be needed when the plate is above the porous layers 105 and 104, which are at the maximum thickness of the plate. At the peripheral flanges, the two casing parts 101 and 102 remain in direct contact due to cold welding. In some cases, the spacer may accommodate an increase in thickness of the first casing 101 and / or the second casing 102 at the first peripheral flange 101A and / or the second peripheral flange 102A.

[0044] The thermally conductive plate 30 also includes a core assembly including a first wicking layer 104 and a second wicking layer 105 within a cavity 103 defined within an outer casing formed by the first casing 101 and the second casing 102. The first wicking layer 104 is disposed adjacent to the first casing 101. The second wicking layer 105 is disposed adjacent to the second casing 102. The core assembly further includes a vapor core 106 disposed between the first wicking layer 104 and the second wicking layer 105. Thus, the sandwiched core subassembly fills the cavity 103 defined between the inner surfaces of the walls of the first casing 102 and the second casing 102, the sandwiched core subassembly being comprised of the first wicking layer 104, the vapor core 106, and the second wicking layer 105.

[0045] As will be appreciated, the first wicking layer 104 and the second wicking layer 105 may be of any shape and / or size, for example, channel-shaped and micrometer (having dimensions less than about 1 mm). The first wicking layer 104 and the second wicking layer 105 may each have a thickness of 0.3 mm to 2 mm, more specifically 0.5 mm to 1.5 mm, more preferably about 1 mm (±10%). They may be formed of continuous ridges or discontinuous fins. The spaces between the fins form a two-dimensional array of interconnected microchannels. The wicking structure may include copper screen mesh, sintered powder, metal foam, and / or metal fibers. The wicking structure may be bonded to a casing. The first wicking layer 104 and the second wicking layer 105 may be a woven metal mesh, a porous metal sintered powder, or a fiber bundle. The size of the pores defined by the first wicking layer 104 and the second wicking layer 105 may be smaller than the thickness and may range from 30 microns to 500 microns. They may include sintered metal powder, screens, and grooved wicks. The first wicking layer 104 and the second wicking layer 105 may be hydrophilic, either by being made from a hydrophilic material or by being treated to be hydrophilic. Any suitable process for making the wicking layer hydrophilic is contemplated, such as oxygen plasma, hydrogen reduction, and thermal oxidation, chemical oxidation. The wicking layer may be sintered on the casing. The wicking layer may include multiple layers of metal mesh. The wicking layer may be formed of an array of pillars or microchannels, the spaces between which function to wick up the liquid. When liquid is present in the wicking layers 104, 105, a meniscus may form, which creates a capillary pressure due to the surface tension of the liquid. In the case of a hydrophilic wicking layer, liquid may be drawn into the wicking layer and towards the zone where the liquid is evaporating. Small pore size increases capillary pressure which may enhance liquid transport. The permeability of the wicking layer may also be affected by the pore size and the tortuosity of the flow path along the pore or microchannel. The wicking layer may have a high ratio of permeability to pore size.High hydrophilicity (low contact angle of fluids) may also be desirable.

[0046] The vapor core 106 may be made of any suitable material having porosity. The vapor core 106 may include a polymeric material such as nylon (e.g., nylon mesh). The vapor core 106 may be used as a spacer inside the cavity 103 to maintain a distance between the first wicking layer 104 and the second wicking layer 105 when the thermally conductive plate 30 is bent as shown in FIG. 1. The vapor core 106 may be made of a metal such as stainless steel. The vapor core 106 may be made of copper. The vapor core 106 may define pores larger than the pores defined by the first wicking layer 104 and the second wicking layer 105 to ensure that the working fluid (e.g., water) is drawn into the first wicking layer 104 and the second wicking layer 105 and releases the vapor core 106 to allow a continuous flow of vapor. In some embodiments, the working fluid may be alcohol, acetone, or methanol. Any suitable combination of fluids may be used as the working fluid. This process is described in more detail below with reference to FIG. 5. The vapor core 106 can be hydrophobic, either by being made of a hydrophobic material or by being treated to be hydrophobic. For example, the vapor core 106 can be coated with a hydrophobic coating. Any suitable process that renders the vapor core 106 hydrophobic is contemplated. The vapor core 106 can include multiple posts or pillars distributed along the cavity 103 to maintain the distance between the two wicking layers. The vapor core 106 can be bonded to the wicking layers 104, 105. When the vapor core 106 is bonded, it can prevent the casings 101, 102 from deforming outwardly when the pressure in the vapor chamber exceeds the ambient pressure. This can occur when the sealed plate is heated above a saturation temperature corresponding to the ambient pressure, e.g., 100° C. at atmospheric pressure.

[0047] The first casing 101 and the second casing 102 may be made of copper. However, copper is a very expensive and dense material, and efforts are being made to limit the use of copper for these reasons. In an alternative embodiment, the first casing 101 may be made of copper clad (e.g., copper with aluminum or stainless steel), while the second casing 102 is a thin copper sheet. A thicker copper clad may provide rigidity to the thermally conductive plate 30. In some embodiments, one of the first casing 101 and the second casing 102 may be part of a battery pack, such as one wall of the casing of the battery pack.

[0048] 4, the first casing part 101 and the second casing part 102 each include two layers, namely the first casing part 101 includes a first inner layer 107 facing the cavity 103 and a first outer layer 108 facing the environment outside the cavity 103. Similarly, the second casing part 102 includes a second inner layer 109 facing the cavity 103 and a second outer layer 110 facing the environment. In this embodiment, the first inner layer 107 and the second inner layer 109 are made of copper, and the first outer layer 108 and the second outer layer 110 are made of aluminum. It will be understood that the first inner layer 107 and the second inner layer 109 can be made of any material that has a high thermal conductivity and is suitably resistant to corrosion due to exposure to the working fluid flowing in the cavity 103. For example, nickel may be used for the inner layers 107, 109. As will be understood below, the material selected to define the inside of the first casing 101 and the second casing 102 should be suitable for cold welding. The first outer layer 108 and the second outer layer 110 may be made of any material having a high thermal conductivity. In some embodiments, the thermal conductivity may be smaller if the thickness of the first outer layer 108 and the second outer layer 110 is small enough to provide a small resistance to heat transfer. Thus, the first casing 101 and the second casing 102 may be made of a clad material such as aluminum copper clad. In the embodiment shown, the thickness of the first casing 101 and the second casing 102 is made up of about 95% of the first outer layer 108 and the second outer layer 110 (e.g., aluminum) and about 5% of the first inner layer 107 and the second inner layer 109 (e.g., copper). For example, if the first casing section 101 is 1 cm thick, the first outer layer 108 may be 9.5 mm thick and the first inner layer 107 may be 0.5 mm thick. In certain embodiments, the first inner layer 107 and the second inner layer 109 may be 50-100 microns thick. As used herein, the term "about" refers to a variation of plus or minus 10%, such that "about 10" includes the range of 9-11.In this embodiment, the thickness of each of the first inner layer 107 and the second inner layer 109 is about 50-100 microns. Having the first casing portion 101 and the second casing portion 102 including a thin layer of copper with a thicker layer of aluminum may provide cost benefits for the manufacture of the thermally conductive plate 30 without compromising the thermal performance of the thermally conductive plate 30.

[0049] In the embodiment shown, the first inner layer 107 and the second inner layer 109 extend all the way to the periphery 33 of the thermally conductive plate 30 such that the first inner layer 107 and the second inner layer 109 may contact each other after the joining process of the first casing 101 and the second casing 102 via their respective peripheral flanges 101A, 102A. However, in some other embodiments, the first inner layer 107 and the second inner layer 109 may overlap only the cavity 103, and the periphery 33 of the thermally conductive plate 30 may be devoid of the first inner layer 107 and the second inner layer 109. In such a case, the first outer layer 108 and the second outer layer 110 may contact each other after the joining of the first casing part 101 and the second casing part 102.

[0050] 5, the different components of the thermally conductive plate 30 described above, the operation of the thermally conductive plate 30 will now be described.

[0051] The thermally conductive plate 30 has a first end 30A, also referred to as the evaporator section, which may be in contact with a thermal component from which heat is to be removed (e.g., a battery). The second end 30B, also referred to as the condenser section, may be in contact with a heat sink to remove heat. The thermally conductive plate 30 is operable to transfer heat from the first end 30A to the second end 30B. For this purpose, the working fluid is present in liquid form in the first wicking layer 104 and the second wicking layer 105. It will be understood that the thermally conductive plate may also transfer heat from the second end 30B towards the first end 30A. In such a case, the second end 30B functions as the evaporator section and the first end 30A functions as the condenser section. When exposed to heat, the working fluid evaporates in a gas phase and travels along arrow A1 towards the cavity 103 containing the vapor core 106. The working fluid in the gas phase then travels along arrow A2 along the vapor core 106 towards the second end 30B of the heat transfer plate 30. Because the second end 30B is cooler than the first end 30A, the working fluid condenses back to a liquid phase and is absorbed by the first wicking layer 104 and the second wicking layer 105 along arrow A3. The working fluid then travels along the first wicking layer 104 and the second wicking layer 105 by capillary action and travels along arrow A4 back towards the first end 30A, and the process begins again. Thus, the heat transfer plate 30 removes heat from the first end 30A by evaporating the working fluid and transfers heat to the second end 30B by condensing the working fluid. These phase changes result in heat being transferred from the first end 30A to the second end 30B. In applications where a component (i.e. a battery) must be heated instead of cooled, then the reverse behavior and direction of liquid and vapor flow is reversed without any modification to the plate structure.

[0052] Now referring to Figures 6A-6C, the steps of manufacturing the heat transfer plate 30 are shown. In the embodiment shown in Figure 6A, the first wicking layer 104 is bonded to the inside of the first casing 101 to obtain a first subassembly. At this point, the working fluid F can be injected inside the first wicking layer 104. As shown in Figure 6B, the second wicking layer 105 can be bonded to the inside of the second casing 102 to obtain a second subassembly. It will be understood that the working fluid F can be injected into one or both of the first wicking layer 104 and the second wicking layer 105. The vapor core 106 is then inserted between the two subassemblies. As shown in Figure 6C, a vacuum can be created to remove air from the cavity defined between the first casing part 101 and the second casing part 102, and the two subassemblies can be bonded together through the periphery of the first casing part 101 and the second casing part 102. As shown in FIG. 6A, the injection of the working fluid may be performed by injecting the working fluid onto the first wicking layer 104. In some cases, the working fluid may be injected throughout the core assembly, including the first wicking layer 104, the second wicking layer 105, and the vapor core 106. As shown in FIG. 6B, disposing the core assembly inside the cavity 103 may include disposing the core assembly between the two casing parts 101, 102. This may be done after or before the injection of the working fluid. As shown in FIG. 6C, the cold welding process may include moving the second casing 102 toward the first casing part 101 along arrow A5 until the peripheral flanges 101A, 102A of the casing part 101 of the first casing part 101 and the second casing part 102 contact each other. The cold welding process may include any suitable cold welding process.

[0053] 7, there is shown another embodiment of a layered structure 200 for a thermally conductive plate 230. For the sake of brevity, only the elements that differ from the layered structure 100 described above are described herein below.

[0054] The layered structure 200 includes a wicking layer 204 located adjacent to the inside of the first casing 101. The wicking layer 204 may be bonded to the inside of the first casing 101 (or the second casing 102). The layered structure 200 includes a vapor core 106 sandwiched between the wicking layer 204 and the second casing 102. Thus, in the embodiment shown, only one layer of wicking material is used.

[0055] 8 and 9, another embodiment of a heat transfer plate is shown at 330. The heat transfer plate 330 includes the first casing 101 and the second casing 102 described herein above. In this embodiment, the vapor core includes a plurality of vapor core strips 306 and the wicking layer includes a plurality of wicking layer strips 304. The vapor core strips 306 and the wicking layer strips 304 are spaced apart from one another as shown in FIG. 9. Each of the wicking layer strips 304 is disposed adjacent to a respective one of the vapor core strips 306. Thus, the staggered arrangement of the wicking layer and vapor core is achieved in a plane parallel to the first casing portion 101 and the second casing portion 102, rather than along a direction perpendicular to the first casing portion 101 and the second casing portion 102. The wicking layer strips 304 and the vapor core strips 306 extend in a direction having a component parallel to the direction of heat transfer.

[0056] In the embodiment shown, the thermally conductive plate is non-uniform and has a single layer that includes both the wicking material and the vapor core material. In the embodiment shown, the strips 304, 306 extend in the direction of heat transport, i.e., between the evaporator end and the condenser end of the thermally conductive plate.

[0057] In some embodiments, no material may be needed for the vapor core strip 306 since the strip of wicking material 304 may be in contact with two walls, thereby supporting the external forces and maintaining the height of the vapor core. In other words, the vapor core strip 306 may be without material. Thus, the liquid and vapor may circulate in the same plane as opposed to on top of each other. This may reduce thickness. This may be interesting for a battery since the heat flux may not be high, but thickness and cost are important.

[0058] 10, a method of manufacturing the heat transfer plate 30, 230, 330 is shown at 1000. The method 1000 includes obtaining a vapor core 106, 306 and a wicking layer 104, 204, 304 at 1002, disposing the vapor core 106, 306 and the wicking layer 104, 204, 304 inside a cavity between two casing parts 101, 102 at 1004, injecting a working fluid F inside the cavity at 1006, applying a vacuum to the cavity at 1008, and cold welding the peripheries of the first casing part 101 and the second casing part 102 together at 1010 after applying the vacuum to the cavity to seal the working fluid inside the cavity. Applying a vacuum to the cavity at 1008 may include, for example, placing the vapor core, wicking layer, and casing inside a vacuum chamber, applying a vacuum within the vacuum chamber, and then injecting working fluid F into the interior of the cavity at 1006. However, it should be understood that in alternative embodiments, a vacuum may alternatively be applied within the cavity, including, for example, not placing the entire casing within the vacuum chamber.

[0059] 3, the method 1000 includes obtaining a second wicking layer 105 and enclosing a vapor core 106 between the first wicking layer 104 and the second wicking layer 105. This may include fixing (e.g., bonding) the first wicking layer 104 to the first casing portion 101 to create a first subassembly, fixing the second wicking layer 105 to the second casing portion 102 to obtain a second subassembly, and enclosing the vapor core 106 between the first subassembly and the second subassembly.

[0060] Alternatively, as shown in FIG. 7, only a single wicking layer 204 is used and is bonded to the first casing part 101, while the vapor core 106 is disposed adjacent to the second casing part 102. The working fluid F may be injected into the single wicking layer 204 and / or the vapor core 106. The vapor core 106 may be bonded to the second casing part 102. The first casing part 101 and the second casing part 102 may be interchangeable. If the heat flux (heating and cooling) is both on the same side, the wicking layer 204 may only be needed on that side. This configuration may reduce costs and allow for thinner thermally conductive plates.

[0061] "Cold welding" as used herein is understood to mean a contact welding or contact joining process, in which little or no heat is used to fuse or otherwise join two metals (in this case the peripheral flanges 101A, 102A of the casing walls). Unlike hot welding (i.e. fusion welding such as arc welding, laser welding, brazing, soldering, etc.) processes, the metals joined by cold welding are not melted by heat. Instead, the energy used to react the cold weld arrives in the form of pressure rather than heat. Thus, the cold welding process as used herein can be carried out at low temperatures, which may include, for example, room temperature. Thus, the process used to cold weld the peripheral flanges 101A, 102A of the casing walls 101B, 102B is carried out at temperatures much lower than 100 degrees Celsius, such as to avoid boiling and rapid evaporation of the working fluid (which may be water) in this heat conducting plate as a result. The amount of working fluid inserted is the sum of the amount of evaporation plus the desired final amount required for proper operation of the device. Therefore, using cold welding to seal the device may allow the device to be filled with working fluid prior to the sealing process, as the first sealing step is performed at high temperature, unlike typical vapor chambers which require sealing in two steps.

[0062] In the embodiment shown, applying a vacuum to the cavity 103 at 1008 includes disposing the vapor core, wicking layer, and casing in a vacuum chamber VC and applying a vacuum to the vacuum chamber VC. Cold welding the periphery, i.e., peripheral flanges 101A, 102A of spaced apart walls 101B, 102B at 1010 may include cold welding the periphery using any suitable cold welding process. Disposing a vapor core and wicking layer inside the cavity 103 at 1004 may include disposing the vapor core and wicking layer inside the cavity 103 defined by the spaced apart walls that are clad with two different materials, which may be aluminum copper or stainless steel copper clad. Injecting a working fluid at 1006 may include injecting water above the recessed portion defined by the first casing portion 101. The working fluid may be injected into the first and / or wicking layers 104, 105 once they are secured to their respective casing portions 101, 102. Even when upside down, the working fluid may remain in the wicking layers due to surface tension. In some embodiments, the working fluid is injected into both the first wicking layer 104 and the second wicking layer 105. The vapor core and wicking layers may be disposed on the first casing portion 101, and injecting the working fluid at 1006 may include injecting the working fluid into the vapor core and the wicking layers. Obtaining the vapor core and wicking layers at 1002 may include obtaining the first wicking layer 104 and the second wicking layer 105, which may be layers of metal foam, sintered metal powder, and / or one or more metal meshes. The first wicking layer 104 may be bonded to one of the spaced apart walls 101B, 102B and the second wicking layer 105 may be bonded to the other of the spaced apart walls 101B, 102B. Obtaining the vapor core 106 at 1002 may include obtaining a vapor core 106 that is a hydrophobic porous layer, a nylon mesh, a polymer mesh, and / or a pillar.

[0063] The method 1000 may include bending the vapor core and wicking layer and the casing into an L-shape before cold welding. The method 1000 may include bending the vapor core and wicking layer and the casing into an L-shape after cold welding. If bending is performed after cold welding at 1010, one of the two casing parts 101, 102 may be provided with pleats at the intersections with the first section 31 and the second section 32 (FIG. 2) of the heat transfer plate 30 such that the bending does not stretch one of the two casing parts 101, 102. These pleats may function as an accordion.

[0064] Application of a vacuum at 1008 may be performed to remove all of the air inside the vacuum chamber VC. This may further have the effect of lowering the pressure inside the cavity 103, thereby lowering the evaporation temperature of the working fluid F (e.g., water). At this point, the periphery of the first casing part 101 may be cold welded to the periphery of the second casing 102 to seal the cavity 103 defined between the first casing part 101 and the second casing 102, thereby enclosing the working fluid F in the cavity 103.

[0065] In this embodiment, the two peripheral flanges 101A, 102A are in contact with each other along the complete continuous perimeter of the thermally conductive plate 30. As a result, no fill tube is needed to create a local gap between the flanges 101A, 102A. Joining the two peripheral flanges 101A, 102A by cold welding under vacuum conditions may allow to avoid the use of a fill tube that is required after a traditional hot welding process. Avoidance of the fill tube may provide the thermally conductive plate 30 without any sharp edges or protrusions along the perimeter of the thermally conductive plate. The thermally conductive plate 30 may therefore be more suitable for use in environments where the thermally conductive plate 30 is located within a pouch cell and the presence of sharp edges may damage the pouch. Similarly, the absence of sharp edges may limit damage to the surrounding wires. The absence of a fill tube may increase the effective contact area between the thermally conductive plate 30 and the battery 12 and heat sink 22. Removal of the tube may reduce the manufacturing cost of the thermally conductive plate 30.

[0066] Brazed. Cold welding minimizes the presence of oxides at the interface between the two casings, provides a clean surface, and may allow the application of high pressure along the entire perimeter of the seal between the two casings.

[0067] In this case, the melting point of one of the two different materials of the cladding material is lower than the welding temperature of the other of the two different materials. As a result, hot welding or traditional welding of copper may not work and is therefore undesirable, since it may melt the aluminum and / or evaporate the working fluid enclosed in the casing. Thus, the melting point of the steam core 106 is lower than the welding temperature of the first casing 101. As a result, hot welding the first casing 101 to the second casing 102 may be harmful to the steam core 106, since it may melt and / or evaporate the fluid inside. Cold welding is used in this embodiment, since it may limit the evaporation of the working fluid.

[0068] 11A-11C, alternative embodiments of thermally conductive plates are shown at 430, 530, 630, respectively. For brevity, only the features that differ from the other thermally conductive plates described above are described below. Thermally conductive plates 430, 530, 630 may include any of the layered structures of thermally conductive plate 30, as described above with reference to FIGS. 4, 7, and 8.

[0069] 11A, the thermally conductive plate 430 has a U-shape and includes an evaporator section 431 and two condenser sections 432 laterally spaced apart from each other on either side of the evaporator section 431. Each of the two condenser sections 432 extends laterally (in this case, upwards) from a respective edge of the evaporator section 431. The evaporator section 431 is connected to the condenser section 432 via insulating sections 433 that form elbows. These insulating sections 433 may be thermally insulated such that heat is neither radiated from nor absorbed by the thermally conductive plate 430 in the insulating sections 433. In the embodiment shown, the elbow defined by the insulating sections 433 defines an angle between the evaporator section 431 and the condenser section 432 at approximately 90 degrees (e.g., 90 degrees ±10%), although other suitable angles may be used.

[0070] 11B, the heat transfer plate 530 has a U-shape and includes two evaporator sections 531 and three condenser sections 532. One of the condenser sections 532 is disposed between the two evaporator sections 531 and is coplanar with the two evaporator sections 531. The other two condenser sections 532 each extend laterally from a respective one of the two evaporator sections 531. Adiabatic sections 533 are used to connect two of the condenser sections 532 to the evaporator section 531, forming an elbow such that the condenser sections 532 are disposed at an angle to the adjacent evaporator section 431.

[0071] 11C, the heat conducting plate 630 has an exemplary shape that can be adjusted to fit any suitable space. In this case, the heat conducting plate 630 includes five evaporator sections 631 and one condenser section 632 interconnected with each other via adiabatic sections 633, and defines an elbow between at least one condenser section 632 and at least one evaporator section 631. Also, more condenser sections may be provided, and fewer or more evaporator sections may be used. Herein, each of the five evaporator sections 631 are parallel to each other but at different heights (i.e., they are non-coplanar), and the condenser section 632 extends generally laterally (and upwards in this case) to the evaporator section 631 at one side edge of the heat conducting plate 630.

[0072] The embodiments described herein provide non-limiting examples of possible implementations of the technology. Upon review of this disclosure, those skilled in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the technology. Further modifications may also be implemented by those skilled in the art in light of this disclosure, which modifications would be within the scope of the technology.

Claims

1. 1. A method for manufacturing a thermally conductive plate having a vapor chamber, comprising: obtaining a vapor core and a wicking layer; disposing the vapor core and the wicking layer within a cavity defined between spaced-apart walls of a casing; injecting a working fluid into the cavity; applying a vacuum to the cavity; and after applying the vacuum to the cavity, cold welding the peripheries of the spaced apart walls together to seal the working fluid, the vapor core, and the wicking layer within the cavity.

2. 2. The method of claim 1, wherein the applying the vacuum to the cavity comprises disposing the vapor core, the wicking layer, and the casing in a vacuum chamber and applying a vacuum to the vacuum chamber.

3. 3. The method of claim 2, wherein the applying the vacuum to the cavity comprises disposing the vapor core, the wicking layer, and the casing inside the vacuum chamber under vacuum before the injecting the working fluid inside the cavity.

4. Obtaining a second wicking layer; and enclosing the vapor core between the wicking layer and the second wicking layer.

5. 4. The method of claim 1, wherein the disposing the vapor core and the wicking layer inside the cavity comprises disposing the vapor core and the wicking layer inside the cavity defined by the spaced apart walls that are claddings of two different materials.

6. 6. The method of claim 5, wherein the disposing the vapor core and the wicking layer within the cavity defined by the spaced-apart walls comprises disposing the vapor core and the wicking layer within the cavity defined by the spaced-apart walls, the cavity being an aluminum copper clad casing or a stainless steel copper clad casing.

7. The method of claim 1 , wherein the injecting of the working fluid comprises injecting water onto a recessed portion defined by a first casing portion of the casing.

8. 8. The method of claim 7, wherein the method includes disposing the vapor core and the wicking layer on the first casing portion, and wherein the injecting the working fluid includes injecting the working fluid into the wicking layer.

9. 4. The method of claim 1, wherein obtaining the vapor core and the wicking layer comprises obtaining the wicking layer, the wicking layer being a layer of metal foam, sintered metal powder, and / or one or more metal meshes.

10. The method of claim 1 , further comprising bonding the wicking layer to one of the spaced apart walls.

11. securing the wicking layer to one of the spaced apart walls to obtain a first subassembly; securing the second wicking layer to the other of the spaced apart walls to obtain a second subassembly; and enclosing the steam core between the first subassembly and the second subassembly.

12. 4. The method of claim 1, further comprising bending the vapor core, the wicking layer, and the casing into a shape defining an elbow prior to the cold welding.

13. 4. The method of claim 1, further comprising, after the cold welding, bending the vapor core, the wicking layer, and the casing into a shape that defines an elbow.

14. 4. The method of claim 1, wherein obtaining the vapor core comprises obtaining the vapor core as a hydrophobic porous layer, a nylon mesh, a polymer mesh, and / or a pillar.

15. 2. The method of claim 1, wherein the vapor core includes a plurality of vapor core strips and the wicking layer includes wicking layer strips, the method further comprising disposing the vapor core strips and the wicking layer strips so as to be spaced apart from one another within the cavity.

16. A thermally conductive plate having a vapor chamber, a first casing and a second casing defining a cavity therebetween; A core assembly comprising: a wicking layer adjacent to the inside of the first casing; a core assembly having a vapor core, the wicking layer and the vapor core being received within the cavity; a working fluid within the cavity; A thermally conductive plate, wherein a first peripheral flange of the first casing is sealingly joined to a second peripheral flange of the second casing along the complete continuous perimeter of the first casing and the second casing, and the first casing is connected to the second casing via the first peripheral flange and the second peripheral flange.

17. The thermally conductive plate of claim 16 , wherein the first casing and the second casing comprise claddings of two different materials.

18. 18. The thermally conductive plate of claim 17, wherein the two different materials include aluminum and copper, and the inside of the first casing and the inside of the second casing are defined by the copper.

19. 18. The thermally conductive plate of claim 17, wherein the melting point of one of the two different materials is less than the hot welding temperature of the other of the two different materials.

20. 20. The thermally conductive plate of any one of claims 16 to 19, wherein the wicking layer comprises a layer of metal foam, sintered metal powder, and / or one or more layers of metal mesh.

21. 20. The thermally conductive plate of any one of claims 16 to 19, wherein the vapor core comprises a hydrophobic porous layer, a nylon mesh, a polymer mesh, and / or pillars.

22. 22. The thermally conductive plate of claim 21, wherein the melting point of the vapor core is below a hot welding temperature of the first casing.

23. 20. The thermal conduction plate of claim 16, wherein the wicking layer is bonded to the first casing, a second wicking layer is bonded to the second casing, and the vapor core is disposed between the wicking layer and the second wicking layer.

24. 20. The thermal conduction plate of claim 16, wherein the wicking layer includes a plurality of wicking layer strips and the vapor core includes a plurality of vapor core strips, the wicking layer strips and the vapor core strips being spaced apart from one another within the cavity.

25. 1. A power module for powering an electrical device, comprising: a housing having an interior volume; a battery located within the interior volume of the housing; A heat sink; a thermally conductive plate, the battery being in a heat exchange relationship with the heat sink via the thermally conductive plate, the thermally conductive plate comprising: a first casing and a second casing defining a cavity therebetween; A core assembly comprising: a wicking layer adjacent to the inside of the first casing; a core assembly having a vapor core, the wicking layer and the vapor core being received within the cavity; a heat transfer plate having a working fluid within the cavity; a first peripheral flange of the first casing is sealingly joined to a second peripheral flange of the second casing along the complete continuous perimeter of the first casing and the second casing, and the first casing is connected to the second casing via the first peripheral flange and the second peripheral flange.

26. 26. The power module of claim 25, wherein the wicking layer is bonded to the first casing, a second wicking layer is bonded to the second casing, and the vapor core is disposed between the wicking layer and the second wicking layer.

27. 26. The power module of claim 25, wherein the wicking layer includes a plurality of wicking layer strips and the vapor core includes a plurality of vapor core strips, the wicking layer strips and the vapor core strips being spaced apart from one another within the cavity.

Images