Power electronic device assembly including double graphite layers and cold plate containing the assembly

Abstract

The present application relates to a power electronics assembly including a dual graphite layer and a cold plate incorporating the assembly. Disclosed are a power electronics assembly, a power electronics assembly, and a cold plate incorporating the power electronics assembly. The power electronics assembly includes a cold plate, the cold plate including a power electronics assembly, and the power electronics assembly including an S-unit and power electronics. The S-unit includes a first graphite layer, a second graphite layer, and a metal layer covering the first and second graphite layers. A groove is formed on the outer surface of the metal layer. The power electronics are arranged within the groove on the outer surface of the S-unit.

Description

Technical Field

[0001] The present description relates generally to power electronic assemblies and, more particularly, to apparatus and methods for power electronic assemblies having low overall thermal resistance while achieving a compact package size. Background Art

[0002] The increasing use of electronics in vehicles is driving the need to make electronic systems more compact. One component of these electronic systems is the power electronics used as switches in inverters. Power electronics have significant cooling requirements due to the heat they generate.

[0003] Furthermore, power electronics, traditionally composed of silicon, are now increasingly being constructed from silicon carbide. The use of silicon carbide generates greater heat flux because it occupies a smaller device footprint. Furthermore, power electronics components often include one or more graphite layers to promote heat dissipation. However, such graphite layers do not provide uniform heat dissipation along every axis.

[0004] For these reasons and others, there is a need to improve cooling of power electronics while maintaining a compact package size. Summary of the Invention

[0005] In one embodiment, a power electronics assembly includes a cold plate, the cold plate including a power electronics assembly, the power electronics assembly including an S-cell and power electronics. The S-cell includes a first graphite layer; a second graphite layer; and a metal layer covering the first and second graphite layers, the metal layer having a groove formed in an outer surface. The power electronics are arranged in the groove on the outer surface of the S-cell.

[0006] In another embodiment, a power electronics assembly includes an S-unit and power electronics. The S-unit includes a first graphite layer; a second graphite layer; and a metal layer covering the first and second graphite layers, wherein a groove is formed in an outer surface of the metal layer. The power electronics are disposed in the groove on the outer surface of the S-unit.

[0007] In yet another embodiment, a power electronics assembly includes a cold plate, the cold plate including a plurality of power electronics components, the power electronics components including an S-unit and power electronics. The S-unit includes a first graphite layer oriented to provide low thermal conductivity along a first axis and high thermal conductivity along second and third axes; a second graphite layer oriented to provide low thermal conductivity along the second axis and high thermal conductivity along the first and third axes; and a metal layer covering the first and second graphite layers, the metal layer having grooves formed in its outer surface. The power electronics are arranged in the grooves on the outer surface of the S-unit. The plurality of power electronics components are embedded in corresponding grooves formed in the surface of the cold plate.

[0008] These and additional features provided by the embodiments described herein will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The embodiments illustrated in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments may be understood when read in conjunction with the following drawings, in which like structures are designated by like reference numerals, and in which:

[0010] Figure 1 schematically depicts a perspective view of an example power electronics assembly according to one or more embodiments described and illustrated herein;

[0011] Figure 2 Schematically depicts a schematic diagram of a system according to one or more embodiments described and illustrated herein. Figure 1 An exploded perspective view of the power electronics components;

[0012] Figure 3 Schematically depicts a system including a plurality of power electronics components according to one or more embodiments described and illustrated herein. Figure 1 A perspective view of a cold plate for a power electronic assembly;

[0013] Figure 4 Schematically depicts a circuit comprising an S-unit and power electronics according to one or more embodiments described and illustrated herein. Figure 3 An exploded perspective view of the power electronics assembly;

[0014] Figure 5 Schematically depicts a schematic diagram of a system according to one or more embodiments described and illustrated herein. Figure 4 A cross-sectional perspective view of a power electronics assembly;

[0015] Figure 6 Schematically depicts a schematic diagram of a system according to one or more embodiments described and illustrated herein. Figure 4 a cross-sectional end view of a power electronics assembly;

[0016] Figure 7 Schematically depicts a schematic diagram of a system according to one or more embodiments described and illustrated herein. Figure 4 An example crystal structure of a first graphite layer and an example crystal structure of a second graphite layer of an S unit;

[0017] Figure 8 Schematically depicts a schematic diagram of a system according to one or more embodiments described and illustrated herein. Figure 4 Another example crystal structure of the first graphite layer and another example crystal structure of the second graphite layer of the S unit;

[0018] Figure 9 schematically depicts a perspective view of another cold plate including a plurality of power electronics components according to one or more embodiments described and illustrated herein; and

[0019] Figure 10 Schematically depicts a schematic diagram of a system according to one or more embodiments shown and described herein. Figure 1 Cross-section of a power electronics component. DETAILED DESCRIPTION

[0020] Embodiments described herein generally relate to a power electronics assembly and a power electronics assembly having a circuit board assembly coupled to a cold plate, the cold plate including the power electronics assembly disposed within corresponding recesses formed in the cold plate. The power electronics may be embedded within recesses formed within an S-cell of each power electronics assembly.

[0021] The power electronics assembly of the present disclosure includes a power electronics device secured to a mounting substrate, referred to herein as an S-cell. As described in more detail below, the S-cell includes a pair of graphite layers that provide enhanced heat dissipation capabilities. In addition, embodiments of the present disclosure include one or more electrical isolation layers that electrically isolate (one or more) power electronics devices from a cold plate. For example, the electrical isolation layer of the S-cell enables the removal of the electrical isolation layer between the printed circuit board and the cold plate, as the electrical isolation is provided by the S-cell itself.

[0022] As described in more detail below, the S-cells of the present disclosure provide enhanced thermal properties by promoting heat flux to the graphite layer of the cold plate. The S-cells described herein include stacked metal layers, graphite layers, and one or more electrically insulating layers in a compact package. Each graphite layer has a 90-degree crystallographic offset to balance the heat diffusion capabilities across the three axes of the graphite layers. The bonding materials described herein for bonding S-cells are particularly well suited for increased thermal conductivity relative to other bonding technologies while also maintaining the ability to electrically isolate the S-cells. The devices, systems, and apparatus described herein improve the heat flux from the S-cell to the cold plate, thereby increasing the heat diffusion and cooling performance of the circuit board assembly.

[0023] The cold plates, power electronics components, circuit board assemblies, power electronics components, etc. described herein may be used in electrified vehicles, such as, but not limited to, electric vehicles, hybrid electric vehicles, any electric motor, generator, industrial tool, household appliance, etc. The various components described herein may be electrically coupled to an electric motor and / or a battery and may be configured as an inverter circuit operable to convert direct current (DC) power to alternating current (AC) power.

[0024] As used herein, "power electronics" refers to any electrical component used to convert DC power to AC power and vice versa. Embodiments may also be used in AC-AC converter and DC-DC converter applications. Non-limiting examples of power electronics include power metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), thyristors, and power transistors.

[0025] As used herein, the phrase "fully embedded" means that every surface of a component is surrounded by the substrate. For example, when a power electronics component is fully embedded by a circuit board substrate, this means that the material of the circuit board substrate covers every surface of the circuit board substrate. A component is "partially embedded" when one or more surfaces of the component are exposed.

[0026] As used herein, an "S-cell" is an element operable to be secured to a mounting substrate of power electronics and includes one or more of a metal layer, a graphite layer, and an electrically insulating layer.

[0027] Various embodiments of the power electronics assembly, power electronics assembly, and cold plate are described in detail below. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0028] Now refer to Figure 1 and Figure 2 , an example power electronics assembly 100 is generally illustrated in assembled and exploded views, respectively. Figure 1 and Figure 2 The power electronic assembly 100 shown in FIG. 1 includes a cold plate 102 and a circuit board assembly 106. The cold plate 102 may be a power electronic device 140 (see FIG. 1 ) coupled to or embedded within a cavity 103 of the cold plate 102 and / or coupled to or embedded within a substrate material of the circuit board assembly 106. Figure 3 ) Any device that removes heat flux. Non-limiting examples of cold plate 102 include heat sinks, single-phase liquid cooling, two-phase liquid cooling, and evaporation chambers.

[0029] Figure 1 and Figure 2 The cold plate 102 is shown configured as a single phase liquid cooling device. The cold plate 102 includes a fluid chamber 115 ( Figure 9 ) of the fluid inlet 132 and the fluid outlet 134. Although Figure 1 and Figure 2 The fluid inlet 132 and the fluid outlet 134 are depicted as being on the same side of the cold plate 102, but the present disclosure is not limited to such an embodiment. That is, in other embodiments, the fluid inlet 132 and the fluid outlet 134 may be positioned on other surfaces of the cold plate 102, such as, for example, adjacent surfaces.

[0030] Still refer to Figure 1 and Figure 2 The circuit board assembly 106 is coupled (eg, such as secured by lamination or any other suitable means) to the first surface 107 of the cold plate 102 . Figure 1 and Figure 2 The circuit board assembly 106 is shown secured to the first surface 107 of the cold plate 102 by fasteners 101 (e.g., bolts and nuts) extending through through-holes 105 of the cold plate 102 and through-holes 109 of the circuit board assembly 106. It should be appreciated that in other embodiments, the through-holes 105, 109 and fasteners 101 may be omitted, as described below.

[0031] In an embodiment, the circuit board assembly 106 may be a 3D printed layer. It should be appreciated that in such an embodiment, the 3D printed layer of the circuit board assembly 106 reduces the overall thermal resistance. In an embodiment, the circuit board assembly 106 may be laminated to the cold plate 102. However, other additive manufacturing processes for securing the circuit board assembly 106 to the cold plate 102 are also contemplated and are within the scope of the present disclosure. Additionally, as described in more detail herein, laser drilling may be used to form holes between the various components of the circuit board assembly 106 and the power electronics 140 ( Figure 4 ) are formed between the power electronics 140 and the conductive layer 110. That is, a through hole is drilled through the circuit board assembly 106 to the top surface of each conductive layer and the power electronics 140. As described in more detail herein, the through holes are then filled with copper via an electroplating method to establish electrical connections between components such as, for example, the power electronics 140, the conductive layer 110, etc. Figure 10 Drawn in .

[0032] Now refer to Figure 3 , shows the cold plate 102 including a plurality of power electronics components 146 positioned within corresponding cavities 103 formed in the first surface 107 of the cold plate 102, as described in more detail herein. As a non-limiting example, the cold plate 102 may include six cavities 103 formed in the first surface 107 of the cold plate 102, arranged in two rows of three, for accommodating six power electronics components 146 for an inverter circuit of an electric vehicle. However, it should be understood that any number of power electronics components 146 may be utilized depending on the application. Similarly, the power electronics components 146 may be arranged in any suitable arrangement, such as in a plurality of rows. Figure 3 A greater or lesser number of rows than shown in FIG are positioned on the first surface 107 of the cold plate 102 .

[0033] Each power electronics assembly 146 includes an S-cell 121 housed within the cavity 103 of the cold plate 102 and power electronics 140 coupled (e.g., secured) to the S-cell 121. As described above, the S-cell 121 is a substrate to which the power electronics 140 is bonded. The S-cell 121 provides a conductive surface area for connection to electrodes on the bottom surface of the power electronics 140. As described in more detail herein, the S-cell 121 also provides a heat spreading function as well as electrical isolation. However, in some embodiments, an electrically insulating layer 180 may be interposed between the S-cell 121 and the bottom wall 104 of the cavity 103 of the cold plate 102 to provide additional electrical isolation.

[0034] Figure 3 104 , an electrically insulating layer 180 is deposited within each cavity 103 of the cold plate 102 between the S-cell 121 and the bottom wall 104 of the cold plate 102 to reduce thermal resistance between the circuit board assembly 106 and the cold plate 102. The electrically insulating layer 180 can generally be any layer that provides electrical insulation, such as a ceramic. In one embodiment, the electrically insulating layer 180 comprises an insulated metal substrate (IMS) dielectric film. The IMS dielectric film can be a solid film layer. In other embodiments, the electrically insulating layer 180 can be a layer of thermal grease. Note that the electrically insulating layer 180 may not have dedicated through-holes.

[0035] Now refer to Figure 4 and Figure 5 , respectively, show an exploded top perspective view and an assembled cross-sectional view of an example S unit 121. The S unit 121 includes a plurality of stacked layers. In particular, Figure 4 and Figure 5 The S unit 121 shown in the figure includes a metal layer 122, a first graphite layer 124A embedded in the metal layer 122, and a second graphite layer 124B. However, as discussed herein, it should be appreciated that additional graphite layers may be provided. The first graphite layer 124A is positioned on top of the second graphite layer 124B. However, it should be appreciated that the first graphite layer 124A and the second graphite layer 124B are interchangeable. The metal layer 122 includes an inner surface 125 and an outer surface 128 opposite the inner surface 125. In an embodiment, the metal layer 122 includes a first metal layer and a second metal layer, wherein the graphite layers 124A, 124B are positioned between the first metal layer and the second metal layer. In an embodiment, the metal layer 122 can be a one-piece, unitary structure rather than comprising a pair of metal layers. The metal layer 122 includes a groove 127 formed in the outer surface 128 of the metal layer 122. The groove 127 is sized to accommodate the power electronics device 140. As described in more detail below, the metal layer 122 provides a conductive surface to which electrodes on the bottom surface of the power electronics device 140 are connected (eg, via direct connection and / or via electrical connection vias). Figure 4 and Figure 5The various layers of the S-unit 121 depicted in FIG. 1 are merely illustrative.

[0036] Note that, Figure 4 and Figure 5 The S unit 121 in the embodiment depicted in FIG includes graphite layers 124A, 124B embedded in a metal layer 122 to provide a Figure 4 and Figure 5 The S-cell 121 is symmetrical about the z-axis as depicted in FIG. The symmetrical nature of the S-cell 121 balances the forces on the S-cell 121 during the high temperature bonding process. Because the metal layer 122 and the graphite layers 124A, 124B have different thermal expansion coefficients, it may be desirable to have a symmetrical substrate stack to balance the thermally induced stresses during the bonding process.

[0037] The metal layer 122 can be made of any suitable metal or alloy. As non-limiting examples, copper and aluminum can be used as the metal layer 122. As described herein, the metal layer 122 of the S unit 121 has a groove 127 formed in an outer surface 128 of the metal layer 122. The groove 127 can be formed by, for example, chemical etching or machining or any other suitable process. The groove 127 has a size and shape to receive the power electronic device 140. The outer surface 128 can generally be a second major surface or surface of the metal layer 122 opposite the inner surface 125 (which is configured as the first major surface or surface of the metal layer 122). That is, the metal layer 122 can be a planar layer whereby the inner surface 125 faces the graphite layers 124A, 124B and the opposing outer surface 128 faces the power electronic device 140 and the circuit board assembly 106 ( Figure 10 ).

[0038] like Figure 4 and Figure 5 As depicted in FIG, S-cell 121 is designed to be rectangular in shape, such that its length dimension is greater than its width dimension. However, as discussed herein, the shape of S-cell 121 is not limited to being rectangular. For example, S-cell 121 may be, for example, square without departing from the scope of this disclosure.

[0039] Now refer to Figure 6, depicts a cross-sectional view of the S unit 121, wherein the first graphite layer 124A and the second graphite layer 124B are shown as being encased within the metal layer 122. In addition, the S unit 121 includes a first brazing layer 190 disposed between the metal layer 122 and the first graphite layer 124A, and a second brazing layer 192 disposed between the metal layer 122 and the second graphite layer 124B opposite the first brazing layer 190. It should be appreciated that the first brazing layer 190 and the second brazing layer 192 are disposed on opposing planar surfaces of the S unit 121 adjacent to the inner surface 125 of the metal layer 122, such that the first brazing layer 190 faces the power electronics 140 ( Figure 5 ) and the second brazing layer 192 faces the cold plate 102 ( Figure 3 ). The S unit 121 also includes a graphite bonding layer 194 disposed between the first graphite layer 124A and the second graphite layer 124B. It should be appreciated that the first brazing layer 190, the second brazing layer 192, and the graphite bonding layer 194 each extend between opposite sides of the metal layer 122 of the S unit 121 along a transverse direction (i.e., a direction parallel to the y-axis of the coordinate axis depicted in the drawings) and a longitudinal direction perpendicular to the transverse direction (i.e., a direction parallel to the x-axis of the coordinate axis depicted in the drawings).

[0040] In an embodiment, the metal layer 122 has a first thickness T1 that is equal to or greater than 0.1 mm and less than or equal to 0.5 mm extending between the inner surface 125 and the outer surface 128. In an embodiment, the metal layer 122 has a first thickness T1 that is equal to or greater than 0.2 mm and less than or equal to 0.3 mm extending between the inner surface 125 and the outer surface 128. In an embodiment, in addition to the groove 127 ( Figure 4 ), the first thickness T1 of the metal layer 122 extends constant around the entire perimeter of the S unit 121. In an embodiment, the first graphite layer 124A has a second thickness T2 equal to or greater than 0.25 mm and less than or equal to 0.75 mm. In an embodiment, the first graphite layer 124A has a second thickness T2 equal to or greater than 0.4 mm and less than or equal to 0.6 mm. In an embodiment, the second graphite layer 124B has a third thickness T3 equal to or greater than 0.25 mm and less than or equal to 0.75 mm. In an embodiment, the second graphite layer 124B has a third thickness T3 equal to or greater than 0.4 mm and less than or equal to 0.6 mm. Therefore, the total thickness of the S unit 121 extending across the first graphite layer 124A and the second graphite layer 124B is equal to or greater than 0.7 mm and less than or equal to 3 mm (i.e., the sum of twice the first thickness T1 of the metal layer 122, the second thickness T2 of the first graphite layer 124A, and the third thickness T3 of the second graphite layer 124B).

[0041] Figure 6 The graphite layers 124A, 124B depicted in the embodiment of FIG. 1 are configured to facilitate heat diffusion through the S-cell 121 and toward the cold plate 102 (see, e.g., FIG. 2 ). Figure 10 ). It should be appreciated that the crystal structure of graphite provides graphite with high thermal conductivity, making it useful for conducting heat flux toward the cold plate 102. However, graphite does not have an isothermal curve. Instead, graphite has a non-isothermal curve with high thermal conductivity along two axes and low thermal conductivity along a third axis. To account for the non-isothermal curve of graphite, each graphite layer 124A, 124B has high thermal conductivity along two axes that is different from the two axes of the other graphite layers 124A, 124B to provide balanced thermal conductivity along each of the three axes of the graphite layers 124A, 124B.

[0042] As a non-limiting example, Figure 7 , depicting the crystal structure of the first graphite layer 124A and the second graphite layer 124B. Specifically, the first graphite layer 124A has high thermal conductivity along the x-axis (in-plane direction) and the z-axis (in-plane direction), and has low thermal conductivity along the y-axis (out-of-plane direction). As described herein, it should be appreciated that reference to low thermal conductivity provides reduced heat diffusion capabilities compared to high thermal conductivity. Therefore, heat diffuses a limited distance along an axis with low thermal conductivity compared to heat diffused along a different axis with high thermal conductivity. The second graphite layer 124B is rotated 90 degrees about the z-axis relative to the first graphite layer 124A, so that the y-axis of the first graphite layer 124A corresponds to the x-axis of the second graphite layer 124B. As a result, the combined heat spreading capabilities of the first and second graphite layers 124A, 124B along the x-axis and y-axis are substantially equal (i.e., within 5%, 10%, 20%, or 30%), rather than being disproportionate to each other as would be the case when only a single graphite layer is used within the S-cell. This enables a higher heat flux and a much lower temperature profile for the power electronics device 140 compared to embodiments in which only a single graphite layer is used and / or the crystal structures of the first and second graphite layers 124A, 124B are oriented in the same direction (i.e., the low thermal conductivity of the graphite layers 124A, 124B extends along the same axis).

[0043] As discussed herein, it should be appreciated that the first graphite layer 124A and the second graphite layer 124B are interchangeable. Thus, the first graphite layer 124A or the second graphite layer 124B can be rotated relative to the other. As another non-limiting example, Figure 8As shown in FIG, the crystal structure of the second graphite layer 124B has high thermal conductivity along the x-axis (in-plane direction) and the z-axis (in-plane direction), and low thermal conductivity along the y-axis (out-of-plane direction). Similarly, the second graphite layer 124B is rotated 90 degrees about the z-axis relative to the first graphite layer 124A, so that the y-axis of the second graphite layer 124B corresponds to the x-axis of the first graphite layer 124A. As a result, the combined thermal diffusion capabilities of the first graphite layer 124A and the second graphite layer 124B along the x-axis and the y-axis remain equal.

[0044] By rotating the graphite layers 124A, 124B relative to each other, this provides the additional benefit of allowing the S-cell 121 to be square rather than rectangular without providing disproportionate heat spreading across the S-cell 121. In embodiments where the crystal structures of the first and second graphite layers 124A, 124B are oriented in the same direction, the shape of the S-cell 121 is typically rectangular to improve heat spreading along the length of the S-cell 121 rather than the width of the S-cell 121 (or vice versa).

[0045] Therefore, if Figure 9 As depicted in FIG, an embodiment of a power electronic assembly 100' is depicted, which includes a cold plate 102 and a plurality of S units 121, each S unit having a square geometry rather than a Figure 3 and Figure 4 The rectangular geometry drawn in . Figure 9 , the heat spreading across the S-cell 121 is shown to be equal across the width of the S-cell 121 and the length of the S-cell 121. In sharp contrast, in embodiments where one of the graphite layers 124A, 124B is not rotated relative to the other, or where only a single graphite layer is used in the S-cell 121, the heat spreading is significantly greater along a corresponding one of the length and width of the corresponding S-cell 121.

[0046] Although not shown herein, it should be appreciated that the power electronics assembly 146 can include more than one pair of graphite layers 124A, 124B. For example, the power electronics assembly 146 can include three, four, or more than four graphite layers positioned in any suitable arrangement, such as, for example, one or more lower graphite layers and one or more upper graphite layers, the one or more upper graphite layers being disposed on the lower graphite layers and rotated 90 degrees relative to the one or more lower graphite layers such that the crystal structure of the lower graphite layers is different from that of the upper graphite layers. As another non-limiting example, the graphite layers can be alternated such that a graphite layer having a crystal structure arranged in a first orientation is interposed between graphite layers having a crystal structure arranged in a second orientation that is different from the first orientation (i.e., offset by 90 degrees).

[0047] Reference again Figure 4, depicts an exploded view of a power electronics assembly 146 including the S-unit 121 and the power electronics 140 . Figure 4 The power electronic device 140 and the bonding layer 143 relative to the groove 127 of the S unit 121 are depicted. The bonding layer 143 can be, for example, a solder layer. As another example, the bonding layer 143 can be a transient liquid phase bonding layer 143. The power electronic device 140 includes a plurality of large electrodes 141 and a plurality of small electrodes 142 on the top surface of the power electronic device 140. The large electrodes 141 can be power electrodes, and the small electrodes 142 can be signal electrodes. Note that although Figure 4 127, the power electronics 140 further includes one or more electrodes on the bottom surface of the power electronics 140. By placing the power electronics 140 into the recess 127, the one or more electrodes on the bottom surface of the power electronics 140 are electrically connected to the metal layer 122. Thus, an electrical connection to the bottom electrode of the power electronics 140 can be formed through the metal layer 122.

[0048] Now refer to Figure 10 , illustrates a cross-sectional view of a power electronic assembly 100. The circuit board assembly 106 includes a substrate 111 made of an electrically insulating material. The electrically insulating material can be a material used to manufacture printed circuit boards, such as, but not limited to, FR-4. The circuit board assembly 106 also includes an embedded conductive layer 110, a plurality of through-holes 112 (conductive through-holes and thermal through-holes). As briefly discussed herein, the through-holes 112 establish electrical connections between components such as, for example, power electronic devices 140, the conductive layer 110, and the like. In some embodiments, the circuit board assembly 106 can include a plurality of power electronic device assemblies 146 fully or partially embedded therein. However, Figure 10 The embodiment depicted in FIG. 1 shows power electronics components 146 housed within an S-unit 121 disposed within the cavity 103 of a cold plate 102 , as described in greater detail herein.

[0049] Cooling fluid (depicted as moving arrows 135) from a reservoir (not shown) flows into the fluid chamber 115 through a fluid inlet 132 and exits the fluid chamber 115 through a fluid outlet 134, where the cooling fluid returns to the reservoir, such as after passing through a heat exchanger (not shown) to remove heat from the cooling fluid. Although not shown, an array of fins may be provided in the fluid chamber 115 to provide additional surface area for heat transfer to the cooling fluid 135.

[0050] From the above, it should be appreciated that what is defined herein is a power electronic component and a method for manufacturing a power electronic component. Specifically, the power electronic component disclosed herein includes a power electronic component comprising a cold plate. The cold plate includes a power electronic device assembly, which includes an S unit and a power electronic device. The S unit includes a first graphite layer, a second graphite layer, and a metal layer covering the first graphite layer and the second graphite layer. A groove is formed in the outer surface of the metal layer. The power electronic device is arranged in the groove on the outer surface of the S unit. In an embodiment, the first graphite layer is oriented to provide low thermal conductivity along the first axis and high thermal conductivity along the second and third axes, and the second graphite layer is oriented to provide low thermal conductivity along the second axis and high thermal conductivity along the first and third axes. Therefore, the thermal distribution of the S unit is substantially equal along the first and second axes.

[0051] It should now be understood that embodiments of the present disclosure relate to a power electronics assembly having a circuit board assembly coupled to a power electronics assembly, the power electronics assembly including a cold plate containing an S-cell. The power electronics can be embedded within the S-cell and / or within the circuit board assembly. This power electronics assembly is compact and provides increased thermal conductivity while maintaining the ability to electrically insulate the S-cell, thereby improving heat flux from the S-cell to the cold plate, thereby increasing heat spreading and cooling performance of the circuit board assembly relative to conventional packaging.

[0052] It is noted that the terms "substantially" and "approximately" may be used herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0053] While specific embodiments have been illustrated and described herein, it will be appreciated that various other changes and modifications may be made without departing from the scope of the claimed subject matter. Furthermore, while various aspects of the claimed subject matter have been described herein, it is not required that these aspects be used in combination. Accordingly, the appended claims are intended to cover all such changes and modifications within the scope of the claimed subject matter.

[0054] It will be apparent to those skilled in the art that various modifications and variations may be made to the embodiments described herein without departing from the scope of the claimed subject matter. Therefore, this specification is intended to cover modifications and variations of the various embodiments described herein as long as these modifications and variations fall within the scope of the appended claims and their equivalents.

Claims

1. A power electronic component comprising: A cold plate, comprising: A power electronic equipment assembly, comprising an S unit and power electronic equipment, wherein: The S unit includes: first graphite layer; a second graphite layer; and a metal layer covering the first graphite layer and the second graphite layer; and The power electronic equipment is arranged in the S unit, wherein the first graphite layer is oriented to provide low thermal conductivity along a first axis and high thermal conductivity along a second axis and a third axis, and The second graphite layer is oriented to provide low thermal conductivity along the second axis and high thermal conductivity along the first axis and the third axis. 2 . The power electronic component of claim 1 , wherein the heat distribution of the S-cell is equal along the first axis and the second axis. The power electronic component of claim 1 , wherein the S-cell has a square shape. 4 . The power electronic component of claim 1 , wherein the first graphite layer and the second graphite layer each have a thickness equal to or greater than 0.2 mm and less than or equal to 0.3 mm. 5 . The power electronics assembly of claim 1 , wherein a plurality of power electronics assembly are embedded within corresponding grooves formed in the surface of the cold plate. 6 . The power electronic assembly of claim 5 , wherein an electrically insulating layer is interposed between each S-cell and the cold plate.

7. A power electronic device assembly, comprising an S unit and power electronic devices, wherein: The S unit includes: first graphite layer; a second graphite layer; and a metal layer covering the first graphite layer and the second graphite layer; and The power electronic equipment is arranged in the S unit, wherein the first graphite layer is oriented to provide low thermal conductivity along a first axis and high thermal conductivity along a second axis and a third axis, and The second graphite layer is oriented to provide low thermal conductivity along the second axis and high thermal conductivity along the first axis and the third axis. 8 . The power electronics assembly of claim 7 , wherein the heat distribution of the S-cell is equal along the first axis and the second axis.

9. The power electronics assembly of claim 7, wherein the S-cell has a square shape. 10 . The power electronics device assembly of claim 7 , wherein the first graphite layer and the second graphite layer each have a thickness equal to or greater than 0.2 mm and less than or equal to 0.3 mm.

11. The power electronics assembly of claim 7, further comprising: a first brazing layer disposed between the metal layer and the first graphite layer; as well as A second solder layer is disposed between the metal layer and the second graphite layer and opposite to the first solder layer.

12. The power electronics assembly of claim 11, further comprising a graphite bonding layer disposed between the first graphite layer and the second graphite layer.

13. A power electronic component comprising: A cold plate, comprising: A plurality of power electronic equipment assemblies, said power electronic equipment assemblies comprising S units and power electronic equipment, wherein: The S unit includes: a first graphite layer oriented to provide low thermal conductivity along a first axis and high thermal conductivity along second and third axes; a second graphite layer oriented to provide low thermal conductivity along the second axis and high thermal conductivity along the first and third axes; and a metal layer covering the first graphite layer and the second graphite layer, wherein a groove is formed in an outer surface of the metal layer; and The power electronic device is arranged in the groove on the outer surface of the S unit, The plurality of power electronic device components are embedded in corresponding grooves formed in the surface of the cold plate. 14 . The power electronic component of claim 13 , wherein the heat distribution of the S-cell is equal along the first axis and the second axis.

15. The power electronic component of claim 13, wherein the S-cell has a square shape. 16 . The power electronic component of claim 13 , wherein the first graphite layer and the second graphite layer each have a thickness equal to or greater than 0.2 mm and less than or equal to 0.3 mm.

17. The power electronic assembly of claim 13, wherein an electrically insulating layer is interposed between each S-cell and the cold plate.

18. The power electronic component of claim 17, wherein the electrically insulating layer comprises an insulated metal substrate dielectric film.

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