Power electronics device assembly including a double graphite layer, and a cooling plate incorporating the power electronics device assembly.

Abstract

To improve the cooling of power electronics devices while maintaining a compact package size. [Solution] A power electronics assembly, a power electronics device assembly, and a cooling plate incorporating a power electronics device assembly are disclosed. The power electronics assembly includes a cooling plate, which includes a power electronics device assembly comprising an S-cell and a power electronics device. The S-cell includes a first graphite layer, a second graphite layer, and a metal layer covering the first and second graphite layers. Recesses are formed within the outer surface of the metal layer. The power electronics device is disposed within the recess on the outer surface of the S-cell.

Description

Technical Field

[0001] This specification generally relates to a power electronics assembly, and more particularly to an apparatus and method for a power electronics assembly that achieves a compact package size while having a low overall thermal resistance.

Background Art

[0002] Due to the increasing use of electronics in vehicles, there is a need to make electronics systems more compact. One component of such an electronics system is a power electronics device used as a switch within an inverter. Power electronics devices require a lot of cooling because heat is generated.

[0003] Furthermore, power electronics devices that were conventionally made of silicon are now tending to be made of silicon carbide. By using silicon carbide, a smaller defined device installation area results, leading to a higher heat flux. Additionally, a power electronics device assembly includes one or more graphite layers to facilitate heat dissipation. However, such graphite layers do not provide uniform heat dissipation capabilities along each axis.

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

Summary of the Invention

[0005] In one embodiment, the power electronics assembly includes a cooling plate, which includes a power electronics device assembly comprising an S-cell and a power electronics device. The S-cell includes a first graphite layer, a second graphite layer, and a metal layer covering the first and second graphite layers, with recesses formed within the outer surface of the metal layer. The power electronics device is disposed within the recesses on the outer surface of the S-cell.

[0006] In another embodiment, the power electronics device assembly includes an S-cell and a power electronics device. The S-cell includes a first graphite layer, a second graphite layer, and a metal layer covering the first and second graphite layers, with recesses formed within the outer surface of the metal layer. The power electronics device is disposed within the recesses on the outer surface of the S-cell.

[0007] In yet another embodiment, the power electronics assembly includes a cooling plate, which includes a plurality of power electronics device assemblies, each containing an S-cell and power electronics devices. The S-cell includes a first graphite layer oriented to provide low thermal conductivity along a first axis and high thermal conductivity along a second and third axis, a second graphite layer oriented to provide low thermal conductivity along a second axis and high thermal conductivity along the first and third axis, and a metal layer covering the first and second graphite layers, with recesses formed within the outer surface of the metal layer. The power electronics devices are arranged within the recesses on the outer surface of the S-cell. The plurality of power electronics device assemblies are incorporated into their respective recesses formed within the plane of the cooling plate.

[0008] These and additional features provided by the embodiments described herein will be better understood in conjunction with the drawings and the following detailed description. [Brief explanation of the drawing]

[0009] The embodiments described in the drawings are essentially illustrative and not intended to limit the subject matter defined by the claims. The following detailed description of the exemplary embodiments can be understood in conjunction with the drawings, in which similar structures are indicated by the same reference numerals. [Figure 1] Figure 1 schematically shows a perspective view of an exemplary power electronics assembly according to one or more embodiments described and explained herein. [Figure 2] Figure 2 schematically shows an exploded perspective view of the power electronics assembly of Figure 1 according to one or more embodiments described and explained herein. [Figure 3] Figure 3 schematically shows a perspective view of the cooling plate of the power electronics assembly of Figure 1, which includes a plurality of power electronics device assemblies according to one or more embodiments described and explained herein. [Figure 4] Figure 4 schematically shows an exploded perspective view of the power electronics device assembly of Figure 3, including an S-cell and a power electronics device, according to one or more embodiments described and explained herein. [Figure 5] Figure 5 schematically shows a cross-sectional perspective view of the power electronics device assembly of Figure 4 according to one or more embodiments described and explained herein. [Figure 6] Figure 6 schematically shows a cross-sectional end view of the power electronics device assembly of Figure 4 according to one or more embodiments described and explained herein. [Figure 7] Figure 7 schematically shows exemplary crystal structures of the first graphite layer and the second graphite layer of the S cell of Figure 4 according to one or more embodiments described herein. [Figure 8] Figure 8 schematically shows another exemplary crystal structure of the first graphite layer and another exemplary crystal structure of the second graphite layer of the S cell of Figure 4, according to one or more embodiments described and explained herein. [Figure 9] Figure 9 schematically shows a perspective view of another cooling plate including a plurality of power electronics device assemblies according to one or more embodiments described and explained herein. [Figure 10] Figure 10 schematically shows a cross-sectional view of the power electronics assembly of Figure 1 according to one or more embodiments shown and described herein. [Modes for carrying out the invention]

[0010] The embodiments described herein generally relate to power electronics assemblies having power electronics device assemblies and circuit board assemblies connected to a cooling plate, wherein the cooling plate includes power electronics device assemblies provided in each recess formed within the cooling plate. Power electronics devices may be incorporated into recesses formed within the S cells of each power electronics device assembly.

[0011] The power electronics device assemblies of this disclosure include power electronics devices mounted on a substrate, which are referred to herein as S-cells. As described in more detail below, the S-cells include a pair of graphite layers that provide enhanced thermal dissipation capabilities. Furthermore, embodiments of this disclosure include one or more electrical insulating layers that electrically insulate the power electronics devices from a cooling plate. Since the electrical insulation is provided by the S-cell itself, for example, the electrical insulating layers of the S-cell make it possible to eliminate the electrical insulating layer between the printed circuit board and the cooling plate.

[0012] As described in more detail below, the S-cells of this disclosure provide improved thermal properties through graphite layers that facilitate heat flux flow toward a cooling plate. The S-cells described herein include a laminated metal, graphite, and one or more electrical insulating layers in a compact package. Each graphite layer has a 90-degree crystalline offset to balance the thermal diffusion capacity across the three axes of the graphite layer. The bonding materials described herein for bonding the S-cells are configured in particular to increase thermal conductivity compared to other bonding techniques while also maintaining the ability to electrically insulate the S-cells. The devices, systems, and apparatus described herein improve the heat flux from the S-cell to the cooling plate, thereby increasing the thermal diffusion and cooling performance of a circuit board assembly.

[0013] The cooling plates, power electronics device assemblies, circuit board assemblies, power electronics assemblies, and similar items described herein may be used in, but are not limited to, electric vehicles, such as electric vehicles, hybrid electric vehicles, any electric motor, generator, industrial tools, household appliances, and similar items. The various assemblies described herein may be electrically connected to an electric motor and / or battery and may be configured as inverter circuits capable of operating to convert direct current (DC) power to alternating current (AC) power.

[0014] As used herein, “power electronics device” means any electrical component used to convert DC power to AC power and vice versa. Embodiments may also be employed in AC-AC converter and DC-DC converter applications. Non-limiting examples of power electronics devices include power metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), thyristors, and power transistors.

[0015] As used herein, the phrase “fully assembled” means that each face of the component is enclosed by the substrate. For example, when a power electronics device assembly is fully assembled by a circuit board, it means that the material of the circuit board covers each face of the circuit board. If one or more faces of a component are exposed, the component is “partially assembled.”

[0016] As used herein, “S-cell” is a mounting substrate operable to be attached to a power electronics device, comprising one or more of a metal layer, a graphite layer, and an electrical insulating layer.

[0017] Various embodiments of power electronics assemblies, power electronics device assemblies, and cooling plates are described in detail below. The same reference numerals are used throughout the drawings whenever possible to refer to the same or similar parts.

[0018] Referring here to Figures 1 and 2, an exemplary power electronics assembly 100 is generally shown in an assembled and exploded view, respectively. The power electronics assembly 100 shown in Figures 1 and 2 includes a cooling plate 102 and a circuit board assembly 106. The cooling plate 102 may be any device capable of removing heat flux from a power electronics device 140 (see Figure 3), which is connected to or incorporated into a hole 103 in the cooling plate 102 and / or connected to or incorporated into the substrate material of the circuit board assembly 106. Non-limiting examples of the cooling plate 102 include a heat sink, single-phase liquid cooling, two-phase liquid cooling, and a vapor chamber.

[0019] Figures 1 and 2 show a cooling plate 102 configured as a single-phase liquid-cooled device. The cooling plate 102 includes a fluid inlet 132 and a fluid outlet 134 that are fluidly connected to a fluid chamber 115 (FIG. 9) within the cooling plate 102. Figures 1 and 2 show the fluid inlet 132 and the fluid outlet 134 on the same side of the cooling plate 102, but the present disclosure is not limited to such embodiments. That is, in other embodiments, the fluid inlet 132 and the fluid outlet 134 may be located on other surfaces of the cooling plate 102, such as an adjacent surface, for example.

[0020] Still referring to FIGS. 1 and 2, the circuit board assembly 106 is connected to the first surface 107 of the cooling plate 102 (e.g., attached by lamination or any other suitable means). FIGS. 1 and 2 show the circuit board assembly 106 as being attached to the first surface 107 of the cooling plate 102 by a fastener 101 (e.g., a bolt and nut) that extends through through-holes 105 in the cooling plate 102 and through-holes 109 in the circuit board assembly 106. It should be understood that in other embodiments, the through-holes 105, 109, and fastener 101 may be omitted as described below.

[0021] In an embodiment, the circuit board assembly 106 can be a 3D printed layer. In such an embodiment, it should be understood that the 3D printed layer of the circuit board assembly 106 reduces the overall thermal resistance. In an embodiment, the circuit board assembly 106 can be laminated to the cooling plate 102. However, other additive manufacturing processes for attaching the circuit board assembly 106 to the cooling plate 102 are also envisioned and are within the scope of this disclosure. Additionally, as described in more detail herein, via connections or vias can be created using laser drilling between various components of the circuit board assembly 106 and the power electronics device 140 (FIG. 4). That is, the vias are drilled through the circuit board assembly 106 to the top surface of each conductive layer and the power electronics device 140. As described in more detail herein, the vias are then filled with copper by an electroplating method to establish electrical connections between components such as, for example, the power electronics device 140, the electrically conductive layer 110, and the like, as shown in FIG. 10.

[0022] Referring now to FIG. 3, the cooling plate 102 is shown to include a plurality of power electronics device assemblies 146 located within respective holes 103 formed within the first surface 107 of the cooling plate 102, as described in more detail herein. As a non-limiting example, the cooling plate 102 can include six holes 103 formed within the first surface 107 of the cooling plate 102 and arranged in two rows of three each to receive six power electronics device assemblies 146 for an inverter circuit of an electric vehicle. However, it should be understood that any number of power electronics device assemblies 146 can be utilized depending on the application. Similarly, the power electronics device assemblies 146 can be located on the first surface 107 of the cooling plate 102 in any suitable arrangement, such as a greater or lesser number of rows than shown in FIG. 3.

[0023] Each power electronics device assembly 146 includes an S-cell 121 received within a hole 103 of a cooling plate 102, and a power electronics device 140 connected to (e.g., mounted) the S-cell 121. As described above, the S-cell 121 is a substrate to which the power electronics device 140 is bonded. The S-cell 121 provides an electrically conductive surface area for making connections to electrodes on the bottom surface of the power electronics device 140. As described in more detail herein, the S-cell 121 further provides thermal diffusion and electrical insulation. However, in some embodiments, an electrical insulation layer 180 may be interposed between the S-cell 121 and the bottom wall 104 of the hole 103 of the cooling plate 102 to provide additional electrical insulation.

[0024] The electrical insulating layer 180 is deposited in each hole 103 of the cooling plate 102 between the S cell 121 and the bottom wall 104 of the cooling plate 102, as shown in Figure 3, to reduce the thermal resistance between the circuit board assembly 106 and the cooling plate 102. The electrical insulating layer 180 can generally be any layer that provides electrical insulation, e.g., ceramic or similar. In some embodiments, the electrical insulating layer 180 includes an insulating metal substrate (IMS) dielectric film. The IMS dielectric film can be a solid film layer. In other embodiments, the electrical insulating layer 180 can be a thermal grease layer. It should be noted that the electrical insulating layer 180 does not necessarily have dedicated through holes.

[0025] Referring here to Figures 4 and 5, exploded top perspective view and assembled cross-sectional view of an exemplary S-cell 121 are shown, respectively. The S-cell 121 comprises a plurality of laminated layers. In particular, the S-cell 121 shown in Figures 4 and 5 includes a metal layer 122 and a first graphite layer 124A and a second graphite layer 124B incorporated within the metal layer 122. However, it should be understood that additional graphite layers may be provided, as described herein. The first graphite layer 124A is located on top of the second graphite layer 124B. However, it should be understood 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 to the inner surface 125. In embodiments, the metal layer 122 includes a first metal layer and a second metal layer, with graphite layers 124A and 124B located between the first and second metal layers. In embodiments, the metal layer 122 may be a single monolithic structure rather than including a pair of metal layers. The metal layer 122 includes a recess 127 formed within the outer surface 128 of the metal layer 122. The recess 127 is sized to accommodate the power electronics device 140. As will be described in more detail below, the metal layer 122 provides an electrically conductive surface to which electrodes at the bottom surface of the power electronics device 140 are connected (e.g., via direct connections and / or via electrical connection vias). It should be understood that the various layers of the S cell 121 shown in Figures 4 and 5 are merely illustrative.

[0026] It should be noted that the S-cell 121 in the embodiments shown in Figures 4 and 5 includes graphite layers 124A and 124B incorporated within the metal layer 122 to provide an S-cell 121 that is symmetrical along the z-axis of the coordinate axes shown in Figures 4 and 5. The symmetry of the S-cell 121 balances the forces on the S-cell 121 during the high-temperature bonding process. Since the metal layer 122 and the graphite layers 124A and 124B have different coefficients of thermal expansion, it may be desirable to have a symmetrical substrate stack to balance the thermally induced stresses during the bonding process.

[0027] The metal layer 122 can be made of any suitable metal or alloy. In non-limiting examples, copper and aluminum may be used as the metal layer 122. As described herein, the metal layer 122 of the S cell 121 has a recess 127 formed within the outer surface 128 of the metal layer 122. The recess 127 may be formed, for example, by chemical etching or machining, or by any other suitable process. The recess 127 has a size and shape such that it can accommodate the power electronics device 140. The outer surface 128 may generally be a second main surface or face of the metal layer 122 opposite the inner surface 125 (configured as the first main surface or face of the metal layer 122). That is, the metal layer 122 may be a planar layer, so that the inner surface 125 faces the graphite layers 124A, 124B, and the opposite outer surface 128 faces the power electronics device 140 and the circuit board assembly 106 (Figure 10).

[0028] As shown in Figures 4 and 5, the S cell 121 is designed to have a rectangular shape such that the length dimension of the S cell 121 is greater than the width dimension of the S cell 121. However, as described herein, the shape of the S cell 121 is not limited to a rectangle. For example, the S cell 121 may be, for example, a square, without departing from the scope of this disclosure.

[0029] Referring now to Figure 6, a cross-sectional view of the S-cell 121 is shown, where the first graphite layer 124A and the second graphite layer 124B are shown covered within the metal layer 122. Furthermore, the S-cell 121 includes a first brazing layer 190 provided between the metal layer 122 and the first graphite layer 124A, and a second brazing layer 192 provided between the metal layer 122 and the second graphite layer 124B on the opposite side of the first brazing layer 190. It should be understood that the first brazing layer 190 and the second brazing layer 192 are provided on opposing planes of the S-cell 121 adjacent to the inner surface 125 of the metal layer 122, such that when assembled, the first brazing layer 190 faces the power electronics device 140 (Figure 5) and the second brazing layer 192 faces the cooling plate 102 (Figure 3). The S cell 121 further includes a graphite bonding layer 194 provided between the first graphite layer 124A and the second graphite layer 124B. It should be understood that the first brazing layer 190, the second brazing layer 192, and the graphite bonding layer 194 each extend between opposing sides of the metal layer 122 of the S cell 121 in the transverse direction (i.e., parallel to the y-axis of the coordinate axes shown in the drawing) and the longitudinal direction perpendicular to the transverse direction (i.e., parallel to the x-axis of the coordinate axes shown in the drawing).

[0030] In the embodiment, the metal layer 122 has a first thickness T1 that extends between the inner surface 125 and the outer surface 128 and is between 0.1 mm and 0.5 mm. In the embodiment, the metal layer 122 has a first thickness T1 that extends between the inner surface 125 and the outer surface 128 and is between 0.2 mm and 0.3 mm. In the embodiment, the first thickness T1 of the metal layer 122, excluding the recess 127 (Figure 4) formed within the outer surface 128 of the metal layer 122, is constant around the entire circumference of the S cell 121. In the embodiment, the first graphite layer 124A has a second thickness T2 that is between 0.25 mm and 0.75 mm. In the embodiment, the first graphite layer 124A has a second thickness T2 that is between 0.4 mm and 0.6 mm. In the embodiment, the second graphite layer 124B has a third thickness T3 that is between 0.25 mm and 0.75 mm. In this embodiment, the second graphite layer 124B has a third thickness T3 of 0.4 mm or more and 0.6 mm or less. Therefore, the total thickness of the S cells 121 extending beyond the first graphite layer 124A and the second graphite layer 124B is 0.7 mm or more and 3 mm or less (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).

[0031] The graphite layers 124A and 124B shown in the embodiment of Figure 6 are provided to facilitate both thermal diffusion across the S cell 121 and thermal diffusion toward the cooling plate 102 (see, for example, Figure 10). It should be understood that the crystalline structure of graphite provides high thermal conductivity to the graphite, making it useful for conducting the heat flux toward the cooling plate 102. However, graphite does not have an isothermal profile. Rather, graphite has a non-isothermal profile, with high conductivity along two axes and low thermal conductivity along a third axis. To account for the non-isothermal profile of graphite, each graphite layer 124A and 124B has high thermal conductivity along two axes different from the two axes of the other graphite layers 124A and 124B, so as to provide balanced thermal conductivity along each of the three axes of the graphite layer 124A and 124B.

[0032] As a non-limiting example, the crystal structures of the first graphite layer 124A and the second graphite layer 124B are shown, as in Figure 7. Specifically, the first graphite layer 124A has high thermal conductivity along the x-axis (in-plane direction) and z-axis (in-plane direction), and low thermal conductivity along the y-axis (out-of-plane direction). As described herein, the reference to low thermal conductivity should be understood as providing a reduced thermal diffusion capacity compared to high thermal conductivity. Thus, heat diffuses over a limited distance along the axis with low thermal conductivity compared to heat diffusing along another axis with high thermal conductivity. The second graphite layer 124B is rotated 90 degrees around the z-axis relative to the first graphite layer 124A such that the y-axis of the first graphite layer 124A corresponds to the x-axis of the second graphite layer 124B. Therefore, the combined thermal diffusion capabilities of the first graphite layer 124A and the second graphite layer 124B are not disproportionate to each other as in the case where only a single graphite layer is used in the S cell, but are substantially equal along the x and y axes (i.e., within the range of 5%, 10%, 20%, or 30%). This results in a higher heat flux and a much lower temperature profile for the power electronics device 140 compared to embodiments where only a single graphite layer is used and / or where the crystal structures of the first graphite layer 124A and the second graphite layer 124B are oriented in the same direction (i.e., the low thermal conductivity of graphite layers 124A and 124B extends along the same axis).

[0033] As described herein, it should be understood that the first graphite layer 124A and the second graphite layer 124B are interchangeable. Therefore, either the first graphite layer 124A or the second graphite layer 124B can be rotated relative to the other. As another non-limiting example, as shown in Figure 8, the crystalline structure of the second graphite layer 124B has high thermal conductivity along the x-axis (in-plane direction) and 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 around the z-axis relative to the first graphite layer 124A such that the y-axis of the second graphite layer 124B corresponds to the x-axis of the first graphite layer 124A. Therefore, the combined thermal diffusion capacity of the first graphite layer 124A and the second graphite layer 124B remains equal along the x and y axes.

[0034] This provides an additional advantage by rotating the graphite layers 124A and 124B relative to each other, which allows the S cell 121 to be square as opposed to rectangular without providing unbalanced thermal diffusion across the S cell 121. In embodiments where the crystal structures of the first graphite layer 124A and the second graphite layer 124B are oriented in the same direction, the S cell 121 is typically rectangular in shape to improve thermal diffusion along the length of the S cell 121 rather than its width, or vice versa.

[0035] Accordingly, as shown in Figure 9, an embodiment of the power electronics assembly 100' includes a cooling plate 102 and a plurality of S cells 121, each having a square outline rather than a rectangular outline as shown in Figures 3 and 4. As shown in Figure 9, the thermal diffusion across the S cells 121 is shown to be equal across both the width and length of the S cells 121. In stark 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 utilized within the S cell 121, the thermal diffusion is significantly greater along the corresponding lengths and widths of the corresponding S cells 121.

[0036] Although not shown herein, it should be understood that the power electronics device assembly 146 may contain more graphite layers than the pair of graphite layers 124A, 124B. For example, the power device assembly 146 may include three, four, or more than four graphite layers located in any preferred arrangement, e.g., one or more lower graphite layers and one or more upper graphite layers provided on the lower graphite layers and rotated 90 degrees relative to one or more lower graphite layers such that the crystal structure of the lower graphite layers differs from that of the upper graphite layers. As another non-limiting example, the graphite layers may be alternating such that graphite layers having a crystal structure arranged in a first orientation are interposed between graphite layers having a crystal structure arranged in a second orientation different from the first orientation, i.e., offset by 90 degrees.

[0037] Referring again to Figure 4, an exploded view of the power electronics device assembly 146, including the S cell 121 and the power electronics device 140, is shown. Figure 4 shows the power electronics device 140 and the bonding layer 143 relative to the recess 127 of the S cell 121. For example, the bonding layer 143 may be a solder layer. As another example, the bonding layer 143 may be a transient liquid phase bonding layer 143. The power electronics device 140 includes a plurality of large electrodes 141 and a plurality of small electrodes 142 on its upper surface. The large electrodes 141 may be power electrodes, while the small electrodes 142 may be signal electrodes. Note that, although not visible in Figure 4, the power electronics device 140 further includes one or more electrodes on its bottom surface. The one or more electrodes on the bottom surface of the power electronics device 140 are electrically connected to the metal layer 122 by placing the power electronics device 140 in the recess 127. Therefore, electrical connection to the bottom electrode of the power electronics device 140 can be made by the metal layer 122.

[0038] Referring here to Figure 10, a cross-sectional view of the power electronics assembly 100 is shown. The circuit board assembly 106 includes a substrate 111 made of an electrically insulating material. The electrically insulating material may be, but is not limited to, a material used in the manufacture of printed circuit boards, for example, FR-4. The circuit board assembly 106 further includes an incorporated electrically conductive layer 110 and a plurality of vias 112 (both electrically conductive vias and thermal vias). As briefly described herein, the vias 112 establish electrical connections between components such as, for example, power electronics devices 140, the electrically conductive layer 110, and the like. In some embodiments, the circuit board assembly 106 may include a plurality of power electronics device assemblies 146 that are fully or partially incorporated within the circuit board assembly 106. However, the embodiment shown in Figure 10 shows a power electronics device assembly 146 that is received in an S-cell 121 located in a hole 103 of a cooling plate 102, as will be described in more detail herein.

[0039] Cooling fluid (indicated as a moving arrow 135) flows from a storage unit (not shown) through a fluid inlet 132 into the fluid chamber 115 and out of the fluid chamber 115 through a fluid outlet 134. The cooling fluid then flows, for example, through a heat exchanger (not shown) to remove heat from the cooling fluid before being returned to the storage unit. Although not shown, an array of fins may be provided in the fluid chamber 115 to provide an additional surface area for heat transfer to the cooling fluid 135.

[0040] From the above, it should be understood that power electronics assemblies and methods for manufacturing power electronics assemblies are defined herein. Specifically, the power electronics assemblies disclosed herein include power electronics assemblies including a cooling plate. The cooling plate includes a power electronics device assembly including an S-cell and a power electronics device. The S-cell includes a first graphite layer, a second graphite layer, and a metal layer covering the first and second graphite layers. Recesses are formed in the outer surface of the metal layer. The power electronics device is disposed in the recess on the outer surface of the S-cell. In embodiments, 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. Thus, the heat distribution of the S-cell is substantially equal along the first and second axes.

[0041] Herein, it should be understood that embodiments of the present disclosure relate to power electronics assemblies having a circuit board assembly connected to a power electronics device assembly including a cooling plate housing an S cell. The power electronics device may be incorporated within the S cell and / or within the circuit board assembly. Such power electronics assemblies are compact and provide increased thermal conductivity while maintaining the ability to electrically isolate the S cell, thereby improving the heat flux from the S cell to the cooling plate, and thereby increasing the thermal diffusion and cooling performance of the circuit board assembly compared to conventional packages.

[0042] It should be noted that the terms “substantial” and “approximately” may be used herein to describe the degree of inherent uncertainty that may arise from any quantitative comparison, value, measurement, or other expression. These terms are also used herein to describe the extent to which quantitative expressions may deviate from the stated criteria without altering the fundamental function of the subject matter in question.

[0043] While specific embodiments are described and documented herein, it should be understood 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 are described herein, such aspects do not need to be used in combination. Accordingly, the appended claims are intended to encompass all such changes and modifications that fall within the scope of the claimed subject matter.

[0044] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the scope of the claimed subject matter. Accordingly, this specification is intended to encompass various modifications and variations to the embodiments described herein, provided that such modifications and variations occur within the scope of the appended claims and their equivalents.

Claims

1. A power electronics assembly comprising a cooling plate, wherein the cooling plate is A power electronics device assembly comprising an S cell, wherein the S cell is The first graphite layer, The second graphite layer, The power electronics device assembly comprises a metal layer covering the first graphite layer and the second graphite layer, wherein a recess is formed in the outer surface of the metal layer. A power electronics device disposed in the recess on the outer surface of the S cell, Equipped with, Power electronics assembly.

2. The first graphite layer is oriented such as to provide low thermal conductivity along the first axis and high thermal conductivity along the second and third axes, 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. The power electronics assembly according to claim 1.

3. The heat distribution of the S cell is substantially equal along the first axis and the second axis. The power electronics assembly according to claim 2.

4. The S cell has a square shape, The power electronics assembly according to claim 2.

5. The first graphite layer and the second graphite layer each have a thickness of 0.2 mm or more and 0.3 mm or less. The power electronics assembly according to claim 2.

6. Multiple power electronics device assemblies are incorporated into their respective recesses formed within the surface of the cooling plate. The power electronics assembly according to claim 1.

7. The electrical insulating layer is interposed between each S cell and the cooling plate. The power electronics assembly according to claim 6.

8. It is an S cell, The first graphite layer, The second graphite layer, The S-cell comprises a metal layer covering the first graphite layer and the second graphite layer, wherein a recess is formed in the outer surface of the metal layer. A power electronics device disposed in the recess on the outer surface of the S cell, Equipped with, Power electronics device assembly.

9. The first graphite layer is oriented such as to provide low thermal conductivity along the first axis and high thermal conductivity along the second and third axes, 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. The power electronics device assembly according to claim 8.

10. The heat distribution of the S cell is substantially equal along the first axis and the second axis. The power electronics device assembly according to claim 9.

11. The S cell has a square shape, The power electronics device assembly according to claim 9.

12. The first graphite layer and the second graphite layer each have a thickness of 0.2 mm or more and 0.3 mm or less. The power electronics device assembly according to claim 9.

13. A first brazing layer is provided between the metal layer and the first graphite layer, A second brazing layer is provided between the metal layer and the second graphite layer on the opposite side of the first brazing layer, It also has, The power electronics device assembly according to claim 8.

14. The present invention further comprises a graphite bonding layer provided between the first graphite layer and the second graphite layer. The power electronics device assembly according to claim 13.

15. A power electronics assembly comprising a cooling plate, wherein the cooling plate comprises a plurality of power electronics device assemblies, It is an S cell, A first graphite layer oriented to provide low thermal conductivity along a first axis and high thermal conductivity along a second and third axis, A second graphite layer oriented to provide low thermal conductivity along the second axis and high thermal conductivity along the first axis and the third axis, The S-cell comprises a metal layer covering the first graphite layer and the second graphite layer, wherein a recess is formed in the outer surface of the metal layer. A power electronics device disposed in the recess on the outer surface of the S cell, The plurality of power electronics device assemblies are provided, and each of the recesses formed in the plane of the cooling plate is incorporated into it. Power electronics assembly.

16. The heat distribution of the S cell is substantially equal along the first axis and the second axis. The power electronics assembly according to claim 15.

17. The S cell has a square shape, The power electronics assembly according to claim 15.

18. The first graphite layer and the second graphite layer each have a thickness of 0.2 mm or more and 0.3 mm or less. The power electronics assembly according to claim 15.

19. The electrical insulating layer is interposed between each S cell and the cooling plate. The power electronics assembly according to claim 15.

20. The aforementioned electrical insulating layer includes an insulating metal substrate dielectric film. The power electronics assembly according to claim 19.

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