Patent Publication Number: US-11665813-B2

Title: Power electronics cooling assemblies and methods for making the same

Description:
TECHNICAL FIELD 
     The present specification relates to power electronics cooling assemblies and methods for making the same. 
     BACKGROUND 
     Power electronics devices embedded in printed circuit boards may be utilized in a variety of applications. For example, in vehicular applications, printed circuit board embedded power electronics devices may be used to convert direct current (DC) into alternating current (AC) to power a motor. In such applications, power electronics devices may be thermally coupled to heat sinks and the like to dissipate heat from the power electronics devices. However, conventional printed circuit board embedded power electronics modules may include one or more intermediate layers positioned between the power electronics device and the heat sink, which may impede the dissipation of heat from the power electronics devices. 
     SUMMARY 
     Accordingly a need exists for improved printed circuit board embedded power electronics modules that reduce thermal resistance between power electronics devices and a heat sink of the power electronics module. Printed circuit board embedded power electronics modules according to the present disclosure generally include power electronics devices in direct contact with conductive substrates that are in direct contact with an electrically-insulating layer. The electrically-insulating layer is in direct contact with a heat sink. The direct contact between the conductive substrates and the heat sink with the electrically-insulating layer minimizes intermediate components positioned between the power electronics devices and the heat sink, thereby minimizing thermal resistance between the power electronics devices and the heat sink. By minimizing thermal resistance between the power electronics devices and the heat sink, the amount of heat dissipated from the power electronics devices can be increased as compared to configurations including intermediate components positioned between the power electronics devices and the heat sink. By increasing the amount of heat that can be dissipated from the power electronics devices, the power electronics devices can be maintained at lower operating temperatures. Additionally, by increasing the amount of heat that can be dissipated from the power electronics devices, the power electronics devices can be operated at higher power outputs while maintaining a similar operating temperature as compared to conventional configurations. 
     In one embodiment, a power electronics module includes a heat sink structurally configured to dissipate thermal energy, an electrically-insulating layer directly contacting the heat sink, a conductive substrate positioned on and in direct contact with the electrically-insulating layer, a power electronics device positioned on and in direct contact with the conductive substrate, a printed circuit board layer that at least partially encapsulates the conductive substrate and the power electronics device, and a driver circuit component positioned on a surface of the printed circuit board layer. 
     In another embodiment, a method for forming a power electronics module includes positioning an electrically-insulating layer on a surface of a heat sink, positioning a conductive substrate on a surface of the electrically-insulating layer opposite the heat sink, positioning a power electronics device on a surface of the conductive substrate opposite the electrically-insulating layer, positioning a printed circuit board layer over the electrically-insulating layer, at least partially embedding the electrically-insulating layer, the conductive substrate, and the power electronics device, and positioning a driver circuit component on a surface of the printed circuit board layer opposite the heat sink. 
     In yet another embodiment, a power electronics module includes a heat sink structurally configured to dissipate thermal energy, an electrically-insulating layer directly contacting the heat sink, a first conductive substrate in direct contact with the electrically-insulating layer, a second conductive substrate in direct contact with the electrically-insulating layer and spaced apart from the first conductive substrate, a first power electronics device positioned on and in direct contact with the first conductive substrate, a second power electronics device positioned on and in direct contact with the second conductive substrate, a conduit extending between and electrically coupling the first power electronics device and the second power electronics device, where the first conductive substrate and the second conductive substrate are positioned between the conduit and the electrically-insulating layer, and a printed circuit board layer that at least partially encapsulates first conductive substrate, the second conductive substrate, the first power electronics device and the second power electronics device. 
     These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description, in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
         FIG.  1    schematically depicts a perspective view of a power electronics module, according to one or more embodiments shown and described herein; 
         FIG.  2    schematically depicts a section view of the power electronics module of  FIG.  1   , according to one or more embodiments shown and described herein; 
         FIG.  3    schematically depicts a perspective view of a heat sink of the power electronics module of  FIG.  1   , according to one or more embodiments shown and described herein; 
         FIG.  4 A  schematically depicts a perspective view of the heat sink of  FIG.  3    and an electrically-insulating layer, according to one or more embodiments shown and described herein; 
         FIG.  4 B  schematically depicts a front view of the heat sink and the electrically-insulating layer of  FIG.  4 A , according to one or more embodiments shown and described herein; 
         FIG.  5    schematically depicts a perspective view of the heat sink and the electrically-insulating layer of  FIG.  4 A  with one or more conductive substrates positioned on the electrically-insulating layer, according to one or more embodiments shown and described herein; 
         FIG.  6    schematically depicts a perspective view of the heat sink, the electrically-insulating layer, the one or more conductive substrates, and one or more power electronics devices positioned on the one or more conductive substrates, according to one or more embodiments shown and described herein; 
         FIG.  7 A  schematically depicts a perspective view of the heat sink, the electrically-insulating layer, the one or more conductive substrates, and the one or more power electronics devices at least partially embedded by a printed circuit board layer, according to one or more embodiments shown and described herein; 
         FIG.  7 B  schematically depicts a section view of the power electronics module of  FIG.  7 A  along section  7 B- 7 B of  FIG.  7 A , according to one or more embodiments shown and described herein; 
         FIG.  8    schematically depicts a perspective view of the power electronics module of  FIG.  7 B  and a clamp, according to one or more embodiments shown and described herein; and 
         FIG.  9    schematically depicts a perspective view of the power electronics module of  FIG.  7 B  and another clamp, according to one or more embodiments shown and described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments described herein are generally directed to power electronics modules including power electronics devices in direct contact with conductive substrates that are in direct contact with an electrically-insulating layer. The electrically-insulating layer is in direct contact with a heat sink. The direct contact between the conductive substrates and the heat sink with the electrically-insulating layer minimizes intermediate components positioned between the power electronics devices and the heat sink, thereby minimizing thermal resistance between the power electronics devices and the heat sink. By minimizing thermal resistance between the power electronics devices and the heat sink, the amount of heat dissipated from the power electronics devices can be increased as compared to configurations including intermediate components positioned between the power electronics devices and the heat sink. By increasing the amount of heat that can be dissipated from the power electronics devices, the power electronics devices can be maintained at lower operating temperatures. Additionally, by increasing the amount of heat that can be dissipated from the power electronics devices, the power electronics devices can be operated at higher power outputs while maintaining a similar operating temperature as compared to conventional configurations. These and other embodiments will now be described with reference to the appended figures. 
     Referring initially to  FIGS.  1  and  2   , a perspective view and a section view of a power electronics module  100  are schematically depicted, respectively. In embodiments, the power electronics module  100  generally includes a heat sink  110 , an electrically-insulating layer  130 , one or more conductive substrates  140 , one or more power electronics devices  150 , a printed circuit board layer  160 , and one or more driver circuit components  170 . 
     Referring to  FIGS.  2  and  3   , a perspective view of the heat sink  110  is schematically depicted. In embodiments, the heat sink  110  is structurally configured to dissipate thermal energy. In some embodiments, the heat sink  110  is a cold plate  112  including an inlet  116  and an outlet  118  through which cooling fluid can pass. For example, cooling fluid may enter the cold plate  112  through the inlet  116 , may flow through one or more fluid passageways  115  within the cold plate  112 , and may exit through the outlet  118 . In embodiments, the heat sink  110  includes one or more fins  120  positioned at least partially within the one or more fluid passageways  115  extending through the heat sink  110 . As the cooling fluid passes through the one or more fluid passageways  115 , the cooling fluid may contact the one or more fins  120 , dissipating heat from the one or more fins  120 , as described in greater detail herein. In embodiments, the one or more fins  120  may include any suitable shape for transferring thermal energy to the cooling fluid, for example and without limitation, plate fins, pin fins, wavy fins, or the like. 
     Referring to  FIGS.  2 ,  4 A, and  4 B , a perspective view and a front view of the heat sink  110  is depicted with the electrically-insulating layer  130 . In embodiments, the electrically-insulating layer  130  directly contacts the heat sink  110 . For example, in the embodiment depicted in  FIG.  4 B , the electrically-insulating layer  130  directly contacts a surface  122  of the heat sink  110 . In some embodiments, the electrically-insulating layer  130  defines one or more through holes  132  that extend through the electrically-insulating layer  130 . The one or more through holes  132  assist in retaining the electrically-insulating layer  130  within the printed circuit board layer  160 , as described in greater detail herein. In some embodiments, the electrically-insulating layer  130  may define one or more fastener holes  135  that extend through the electrically-insulating layer  130 . Mechanical fasteners, such as bolts or the like, can be inserted within the one or more fastener holes  135  to couple components (e.g., a clamp  180  as shown in  FIGS.  8  and  9   ) to the electrically-insulating layer  130  and/or the printed circuit board layer  160 . In embodiments, the electrically-insulating layer  130  is formed of a material that restricts the flow of electrical current, for example and without limitation, Alumina (Al 2 O 3 ), Aluminum Nitride (AIN), Beryllium Oxide (BeO), or the like. 
     Referring to  FIGS.  2  and  5   , a perspective view of the heat sink  110 , the electrically-insulating layer  130 , and the one or more conductive substrates  140  is schematically depicted. In embodiments, the one or more conductive substrates  140  directly contact the electrically-insulating layer  130 . For example, in the embodiment depicted in  FIG.  5   , the one or more conductive substrates  140  are positioned on a surface  134  of the electrically-insulating layer  130  opposite the heat sink  110 . In some embodiments, the one or more conductive substrates  140  are spaced apart from one another on the electrically-insulating layer  130 . In this way, in some embodiments, the one or more conductive substrates  140  may be electrically isolated from one another. While in the embodiment depicted in  FIG.  5    the power electronics module  100  includes six conductive substrates  140 , it should be understood that this is merely an example, and power electronics modules  100  according to the present disclosure may include any suitable number of conductive substrates  140  positioned on the electrically-insulating layer  130 . In embodiments, the one or more conductive substrates  140  may be formed of an electrically conductive metal, such as copper or the like. 
     In some embodiments, the one or more conductive substrates  140  may define cavities  142  extending inwardly into the one or more conductive substrates  140 . The one or more power electronics devices  150  ( FIG.  1   ) may be positioned at least partially within the cavities  142 , as described in greater detail herein. 
     For example and referring to  FIGS.  2  and  6   , a perspective view of the heat sink  110 , the electrically-insulating layer  130 , the one or more conductive substrates  140 , and one or more power electronics devices  150  is schematically depicted. The one or more power electronics devices  150 , in embodiments, may directly contact the one or more conductive substrates  140 . For example, in some embodiments, the one or more power electronics devices  150  may be positioned within associated cavities  142  of the one or more conductive substrates  140 . In some embodiments, the one or more power electronics devices  150  are electrically coupled to the one or more conductive substrates  140 . 
     In some embodiments, the one or more power electronics devices  150  may be coupled to the one or more conductive substrates  140  through any suitable connection, for example and without limitation, a sintered connection, a soldered connection, a welded connection, or the like. In embodiments, the one or more power electronics devices  150  may include any suitable device a semiconductor device such as, but not limited to, an insulated gate bipolar transistor (IGBT), a reverse conducting IGBT (RC-IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), a power MOSFET, a diode, a transistor, and/or combinations thereof. In some embodiments, the power electronics device  150  may include a wide-bandgap semiconductor, and may be formed from any suitable material such as, but not limited to, silicon carbide (SiC), silicon dioxide (SiO 2 ), aluminum nitride (AlN), gallium nitride (GaN), and boron nitride (BN), and the like. In some embodiments, the power electronics device  150  may operate at high current and under high temperatures, for example in excess of 250° C. 
     Referring to  FIGS.  2 ,  7 A, and  7 B  a perspective view and a section view of the heat sink  110 , the electrically-insulating layer  130 , the one or more conductive substrates  140 , the one or more power electronics devices  150 , and the printed circuit board layer  160  is schematically depicted. With the one or more power electronics devices  150  positioned on and coupled to the one or more conductive substrates  140 , the printed circuit board layer  160  may be positioned over the electrically-insulating layer  130 , at least partially embedding the electrically-insulating layer  130 , the one or more conductive substrates  140 , and the one or more power electronics devices  150 . In some embodiments, the printed circuit board layer  160  may include any suitable material, for example and without limitation, laminates, cotton paper, epoxy, woven glass, matte glass, polyester, or the like and combinations thereof. 
     In some embodiments and as shown in  FIG.  7 B , the printed circuit board layer  160  may extend through the through holes  132 , which may assist in bonding the printed circuit board layer  160  to the electrically-insulating layer  130 . 
     In some embodiments, the printed circuit board layer  160  may include a conductive surface  162  through which components positioned on the conductive surface  162  can be electrically coupled to one another. For example and referring to  FIG.  2   , in some embodiments, one or more driver circuit components  170  may be coupled to the conductive surface  162  of the printed circuit board layer  160 . In embodiments, the conductive surface  162  of the printed circuit board layer  160  may be formed of any suitable conductor, for example and without limitation, copper or the like. In the embodiment depicted in  FIG.  2   , the power electronics module  100  comprises six driver circuit components  170 , however, it should be understood that power electronics modules  100  according to the present disclosure may include any suitable number of driver circuit components  170 . In embodiments, one or more of the driver circuit components  170  may be electrically coupled to one another through the conductive surface  162  of the printed circuit board layer  160 . The driver circuit components  170  may include any suitable components or circuitry for controlling operation of the power electronics module  100 . 
     In some embodiments and referring to  FIG.  2   , the power electronics module  100  includes one or more conduits  154  for electrically coupling the one or more power electronics devices  150 . In embodiments, the conduits  154 ,  154 ′,  154 ″, and  154 ′″ may be utilized to connect positive, negative, and/or ground connections to the one or more power electronics devices  150 . In some embodiments, the power electronics module  100  includes a conduit  154 ′ that extends between a first power electronics device  150  and a second power electronics device  150  and electrically couples the first power electronics device  150  to the second power electronics device  150 . In some embodiments, the first power electronics device  150  may be electrically coupled to the second power electronics device  150  through the conduit  154 ′ and one or more of the conductive substrates  140 . In embodiments, the power electronics devices  150  and the conductive substrates  140  are positioned between one or more of the conduits  154 ,  154 ′,  154 ″, and  154 ′″ and the electrically-insulating layer  130 . For example, in the orientation depicted in  FIG.  2   , the conduits  154 ,  154 ′,  154 ″, and  154 ′″ are positioned above the power electronics devices  150 . By positioning the power electronics devices  150  between the conduits  154 ,  154 ′,  154 ″, and  154 ′″ and the electrically-insulating layer  130 , the power electronics devices  150  may be positioned in direct contact with the conductive substrates  140 , and the conductive substrates  140  may be positioned in direct contact with the electrically-insulating layer  130 . Put another way, by positioning the power electronics devices  150  between the conduits  154 ,  154 ′,  154 ″, and  154 ′″ and the electrically-insulating layer  130 , the power electronics devices  150  may be positioned closer to the electrically-insulating layer  130  (and accordingly the heat sink  110 ) as compared to configurations in which the conduits  154 ,  154 ′,  154 ″, and  154 ′″ are positioned between the power electronics devices  150  and the electrically-insulating layer  130 . While in the section view depicted in  FIG.  2    the conduits  154 ,  154 ′,  154 ″, and  154 ′″ are shown connecting two of the power electronics devices  150 , it should be understood that some or all of the power electronics devices  150  of the power electronics module  100  can be coupled to one another by conduits. Further, while in the section view depicted in  FIG.  2    the conduits  154 ,  154 ′,  154 ″, and  154 ′″ are shown at different vertical positions above the power electronics devices  150 , it should be understood that the conduits  154 ,  154 ′,  154 ″, and  154 ′″ may be positioned at the same or at different heights. 
     In embodiments, by positioning the power electronics devices  150  in direct contact with conductive substrates  140  that are in direct contact with the electrically-insulating layer  130 , thermal resistance between the electrically-insulating layer  130  and the power electronics devices  150  can be minimized. Further, by positioning the electrically-insulating layer  130  in direct contact with the heat sink  110 , thermal resistance between the electrically-insulating layer  130  and the heat sink  110  can be minimized, thereby minimizing thermal resistance between the power electronics devices  150  and the heat sink  110 . In this way, the amount of heat transferred from the power electronics devices  150  to the heat sink  110  can be increased as compared to configurations including intervening layers between the power electronics devices  150  and the conductive substrates  140 , between the conductive substrates  140  and the electrically-insulating layer  130 , or between the electrically-insulating layer  130  and the heat sink  110 . By increasing the amount of heat transferred from the power electronics devices  150 , the power electronics devices  150  may be maintained at a lower operating temperature. Alternatively, the power electronics devices  150  may operate at an increased power output as compared to conventional configurations while being maintained at a similar operating temperature. 
     Referring to  FIG.  8    in some embodiments, the power electronics module  100  includes a clamp  180  that can be coupled to the heat sink  110 , the electrically-insulating layer  130  ( FIG.  7 B ), and/or the printed circuit board layer  160 . The clamp  180 , in embodiments, generally extends around the heat sink  110 , and may at least partially encapsulate the heat sink  110 . The clamp  180  may be coupled to the heat sink  110 , the electrically-insulating layer  130  ( FIG.  7 B ), and/or the printed circuit board layer  160  in any suitable manner, for example through mechanical fasteners such as bolts. The clamp  180  may support the heat sink  110 , the electrically-insulating layer  130  ( FIG.  7 B ), and/or the printed circuit board layer  160 , and may resist torsional forces applied to the heat sink  110 , the electrically-insulating layer  130  ( FIG.  7 B ), and/or the printed circuit board layer  160 . While in the embodiment depicted in  FIG.  8    the clamp  180  is shown as a planar structure, it should be understood that this is merely an example, and the clamp  180  may include any suitable structure to resist torsional forces. 
     For example and referring to  FIG.  9   , in some embodiments, the clamp  180  may include a cross or X-shape coupled to opposing corners of the heat sink  110 , the electrically-insulating layer  130  ( FIG.  7 B ), and/or the printed circuit board layer  160 . 
     It should now be understood that embodiments described herein are generally directed to power electronics modules including power electronics devices in direct contact with conductive substrates that are in direct contact with an electrically-insulating layer. The electrically-insulating layer is in direct contact with a heat sink. The direct contact between the conductive substrates and the heat sink with the electrically-insulating layer minimizes intermediate components positioned between the power electronics devices and the heat sink, thereby minimizing thermal resistance between the power electronics devices and the heat sink. By minimizing thermal resistance between the power electronics devices and the heat sink, the amount of heat dissipated from the power electronics devices can be increased as compared to configurations including intermediate components positioned between the power electronics devices and the heat sink. By increasing the amount of heat that can be dissipated from the power electronics devices, the power electronics devices can be maintained at lower operating temperatures. Additionally, by increasing the amount of heat that can be dissipated from the power electronics devices, the power electronics devices can be operated at higher power outputs while maintaining a similar operating temperature as compared to conventional configurations. These and other embodiments will now be described with reference to the appended figures. 
     Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it is noted that the various details described in this disclosure should not be taken to imply that these details relate to elements that are essential components of the various embodiments described in this disclosure, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Rather, the appended claims should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described in this disclosure. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various described embodiments provided such modification and variations come within the scope of the appended claims and their equivalents. 
     It is noted that recitations herein of a component of the present disclosure being “structurally configured” in a particular way, to embody a particular property, or to function in a particular manner, are structural recitations, as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “structurally configured” denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural characteristics of the component. 
     It is noted that terms like “preferably,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure. 
     For the purposes of describing and defining the present invention it is noted that the terms “substantially” and “about” are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms “substantially” and “about” 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. 
     It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present invention, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”