Cold Plates for Power Electronic Systems

Abstract

To disclose the Energy Management Unit (EMU).SOLUTION: The EMU includes a cold plate sandwiched between the first printed circuit board (PCB) and the second PCB, the cold plate includes one or more magnetic elements, and the cold plate is configured to cool both the first PCB and the second PCB.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to electric vehicle on-board chargers (OBCs) and DC-DC converters, and more particularly to the magnetic, mechanical and thermal interfaces for power electronics subassemblies. [Background technology]

[0002] Typically in automotive applications, power magnetics are air-cooled or directly bonded to a cold plate with one surface liquid-cooled. Power electronic magnetics such as these are oversized because the heat dissipation flux path is one-dimensional. In addition, typical magnetics require complex solder connections to subassemblies that include blade connectors or are soldered directly to the board.

[0003] High power and high density power supplies typically include a cold plate to which both the power silicon and power magnetics are attached. After the power supply is assembled, access to the printed circuit board (PCB) or the ability to remove the PCB for completion of line testing is difficult or in some cases completely impossible. This is because the switching silicon devices are typically bolted to the cold plate (directly or via PCB mounting bolts), while the magnetics are potted to the cold plate with a thermally conductive material and both components are soldered directly to the PCB. [Brief description of the drawings]

[0004] [Figure 1] 1 provides a perspective view of an exemplary energy management unit, according to one embodiment of the disclosure.

[0005] [Diagram 2] 1 provides an exploded view of an exemplary cooling manifold according to one embodiment of the disclosure.

[0006] [Diagram 3]1 illustrates details of an exemplary magnetics interface to a PCB, according to one embodiment of the present disclosure.

[0007] [Figure 4a] 4 provides a detailed view of the functionality of each particular feature of the magnetic-threaded interface to the PCB of FIG. 3 in accordance with one embodiment of the present disclosure. [Figure 4b] 4 provides a detailed view of the functionality of each particular feature of the magnetic-threaded interface to the PCB of FIG. 3 in accordance with one embodiment of the present disclosure.

[0008] [Diagram 5] 1 illustrates exemplary steps in a thread interface manufacturing process according to one embodiment of the present disclosure.

[0009] [Figure 6a] 6A-6C show the thread interface of FIG. 5 at different stages of the manufacturing process according to one embodiment of the present disclosure. [Figure 6b] 6A-6C show the thread interface of FIG. 5 at different stages of the manufacturing process according to one embodiment of the present disclosure. [Figure 6c] 6A-6C show the thread interface of FIG. 5 at different stages of the manufacturing process according to one embodiment of the present disclosure. Summary of the Invention

[0010] One aspect of the present disclosure relates to a shared cold plate manifold that cools two power electronics PCBs on each side, e.g., a DC-DC on one side and an OBC on the other side, reducing parts, cost, and size of the power electronics assembly.

[0011] A second aspect of the present disclosure relates to a cold plate manifold that allows low pressure and high flow rate coolant to pass through, enables an energy management unit (EMU) to be implemented within the battery cooling loop and battery pack housing, eliminates bulky connectors and housings, reduces weight, space and cost, and improves reliability.

[0012] A third aspect of the present disclosure relates to a cold plate manifold that contains magnetic elements and reliably cools and seals multiple (e.g., six) magnetic surfaces, allowing for superior cooling and further miniaturization of energy storage or transfer devices.

[0013] A fourth aspect of the present disclosure relates to a magnetic assembly that includes a threaded interface to facilitate assembly and allow low impedance contact between the magnetic body and the PCB while simultaneously providing a robust mechanical connection against vibration and reacting to compressive pressure of the thermal interface material locally against the magnetic screw. The magnetic screw terminal simultaneously serves as a standoff for the PCB.

[0014] A fifth aspect of the present disclosure relates to a process for constructing a magnetic body having a threaded interface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In the following description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, specific embodiments which may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the embodiments of the present disclosure.

[0016] 1 illustrates an exemplary EMU 110 according to one embodiment of the disclosure. The EMU 110 includes a shared cold plate manifold ("cold plate") 100 capable of cooling two power electronics PCBs on each side, e.g., a DC-DC PCB 112 on one side and an OBC 102 on the other side. By making the cold plate 100 multi-layered, the footprint of the magnetics 108 can overlap with the footprint of the power silicon and other PCB components 102. This is accomplished by stacking the cold plate 100 into a multi-layer assembly, as shown in FIG.

[0017] As shown in FIG. 2, the two outer layers 4, 2 of the multi-layer assembly 10 comprise the end lid manifolds to which the power silicon devices are attached. The next two inner pieces 3, 5 on either side are sealing gaskets. In the illustrated embodiment, the sealing gasket 5 may be a simple O-ring, while the sealing gasket 3 may be a gasket plate with an asymmetrical sealing surface on either side that helps seal around the magnetic reeds 9 to the outside while allowing the coolant to flow over the magnetics and around the reeds. It should be understood that other types of sealing gaskets may be used depending on the sealing requirements.

[0018] The inside of the gasket plate 5 seals around the top of the magnetic pockets in the cold block (or center block) 1, and the outside seals around the magnetic leads 9 in the end plate manifold 2. The gasket plate 3 allows the coolant (not shown in FIG. 2) to flow over the top of the magnetics 6, 8, and the common mode chokes (CMCs) 11, 12 allow the coolant to flow just underneath the bottom of the field effect transistors (FETs) mounted on the outside of the lid manifold 2. This gasket plate 3 routes the coolant in and out of the lid manifold 2 as it passes through the center plate 1. The final layer of the cold plate is the center block 1. The magnetics 6, 8 and CMCs 11, 12 are potted to the center plate. This multi-layer cold plate 10 allows for higher packing and power density.

[0019] Referring back to Figure 1, it will also be noted that the large inlet 104 and outlet 106 support high volume coolant flow at low pressure. In an embodiment of the present disclosure, the magnetic body 108 is submerged and cooled on all surfaces including the perimeter and top and bottom. Additionally, a manifold with a sealant gasket, such as that shown in Figure 2, allows for high flow rates. These combined features allow the magnetic body 108 to be compact.

[0020] Manufacturing costs can be kept low by using conventional manufacturing processes for similar sealing gasket plates used in automatic transmissions. The gaskets 3, 5 shown in FIG. 2 can maintain high pressure seals for the complex cooling channels. The exemplary energy management unit disclosed in these embodiments allows for ultra-high flow rates (up to about 30 LPM) and allows the EMU coolant to be in series with the battery pack, which provides an advantage when the EMU is implemented within the battery pack enclosure.

[0021] 3 shows details of an exemplary magnetic interface of the multi-layer assembly 10 to a PCB. In this embodiment, to facilitate assembly of the cold block 310, the magnetic element is fitted with a threaded interface 302 that allows a threaded interface 304 to provide both an electrical connection between the magnetic element 300 and the PCB 308 and a mechanical connection that secures the PCB 308 to the cold block 310. This mechanical interface can replace traditional standoffs and can provide a localized means of reaching compressive forces in the thermal interface gap pad material used under the power silicon devices.

[0022] 4a and 4b provide detailed views of an exemplary magnetic screw interface (302 in FIG. 3) to the PCB of the magnetic body. As shown in FIG. 4a and 4b, a fixed screw terminal 404 is utilized to allow the PCB to be easily assembled to and detachable (solderless) from the magnetic terminal 404 of the magnetic body. If the magnetic body 406 is deeply embedded (potted) in the cold plate, the magnetic terminal 404 can also be utilized to fasten the PCB (not shown in FIG. 4) to the cold plate. If the magnetic screw terminal 402 also serves as the mounting point for the PCB, the fastening screw 408 of the power silicon can also be removed and the PCB can apply a preload to the thermal interface material 410 under the power silicone package to hold the power silicone package in place. This is all accomplished with the ABS plastic magnetic end cap 412 as shown in FIG. 4.

[0023] The end cap 412 sits on top of the magnetic core 406 and is held in place by the bottom plate (2 in FIG. 2). Additionally, the screw terminals 404 can be plated to have a compatible material interface with the PCB. This can include any combination of electroless nickel immersion gold (ENIG), copper, gold, or nickel. The magnetic end cap accomplishes all of these functions through a specific shape shown in FIG. 4. Notably, in this embodiment, the hex screw terminals 404 can transmit screw torque to the plastic end cap 412 through the hex shape of the base. The end cap 412 can then transmit torque to the cold block 406 through the outer shape of the perimeter.

[0024] FIG. 5 is a flow chart illustrating exemplary steps in a thread interface manufacturing process, according to one embodiment of the present disclosure. Specifically, FIG. 5 illustrates a process for assembling a magnetic lead. First, the screw terminals are inserted into a fixture (step 501). Next, the magnetic component is placed into the fixture, which positions all the screw terminals against the top surface of the magnetic core (step 502). Next, the leads coming out of the magnetic component are soldered or welded to the screw terminals (step 503). The assembly is then removed from the fixture, and optionally varnish is applied to the solder joints (step 504). A magnetic end cap is installed and the cup is screwed down to bring all the screw terminals up to the same height before the potting process (step 505). Finally, a hold-down fixture is used to place the assembly into a cold block, and thermal potting is applied (step 506). It should be understood that some of the steps illustrated in FIG. 5 may be performed in parallel or in a different order, to the extent that the same results may be achieved.

[0025] Figure 6a shows a partially fabricated thread interface 600 in a fixture 604 after steps 501-504 of Figure 5 have been performed. The screw terminals (collectively 602) are inserted into the fixture 604. The magnetic material 606 is placed into the fixture 604 and bolted down. The fixture 604 positions all of the screw terminals 602 against a planar top surface. The leads coming out of the magnetic components are soldered or welded to the screw terminals 602.

[0026] Figure 6b shows a further assembled thread interface 600' after step 505 of Figure 5 has been performed. The partially assembled thread interface 600' has been removed from the fixture and varnish has optionally been applied to the solder joints (collectively 608).

[0027] FIG. 6c shows the thread interface 600″ during step 506 of FIG. 5. The magnetic end cap 610 is installed and the cup 612 is screwed down to bring all the screw terminals up to the same height before the potting process. The thread interface 600″ is then placed into a cold block (not shown in FIG. 6c).

[0028] Although the embodiments of the present disclosure have been fully described with reference to the accompanying drawings, it should be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications should be understood as being included within the scope of the embodiments of the present disclosure as defined by the appended claims. It should be noted that the present invention may include the following aspects. [Aspect 1] 1. An energy management unit (EMU), comprising: a cold plate sandwiched between a first printed circuit board (PCB) and a second PCB, the cold plate comprising one or more magnetic materials; the cold plate is configured to cool both the first PCB and the second PCB; Energy Management Unit (EMU). [Aspect 2] 2. The EMU of embodiment 1, wherein the first PCB includes a DC-DC PCB and the second PCB includes an on-board charger (OBC) PCB. [Aspect 3] 2. The EMU of embodiment 1, wherein the cold plate comprises one or more magnetic pockets configured to hold the one or more magnetic bodies. [Aspect 4] The cold plate is a top outer layer and a bottom outer layer, both of which include end lid manifolds to which the power silicon devices are attached; The EMU of embodiment 3, comprising multiple layers. [Aspect 5] The EMU of embodiment 4, wherein the cold plate further comprises a first sealing gasket inside the top outer layer and a second sealing gasket inside the bottom outer layer. [Aspect 6] The EMU of embodiment 5, wherein the first sealing gasket comprises an O-ring gasket. [Aspect 6] The EMU of embodiment 4, wherein the second sealing gasket comprises a gasket plate having asymmetric sealing surfaces on both sides. [Aspect 7] The EMU of embodiment 4, wherein the first sealing gasket is configured to seal around an upper side of the one or more magnetic pockets. [Aspect 8] The EMU of embodiment 4, wherein the second sealing gasket is configured to seal around one or more magnetic leads of the one or more magnetic bodies. [Aspect 9] The EMU of embodiment 8, wherein the second sealing gasket is configured to allow coolant to flow over the one or more magnetic bodies and directly beneath a bottom of a field effect transistor (FET) mounted outside the bottom outer layer. [Aspect 10] The EMU of embodiment 8, wherein the second sealing gasket is configured to route the coolant between the inside and the outside of the bottom outer layer as the coolant passes through the cold plate. [Aspect 11] A magnetic interface of the cold plate, a threaded interface that provides both an electrical connection between the one or more magnetic bodies and the first PCB and a mechanical connection that secures the first PCB to the cold plate; The EMU of embodiment 1, further comprising a magnetic interface. [Aspect 12] The EMU of embodiment 11, further comprising an end cap on top of the one or more magnetic bodies. [Aspect 13] The EMU of embodiment 11, wherein the threaded interface includes a compatible material interface with the first PCB. [Aspect 14] 14. The EMU of embodiment 13, wherein the compatible material interface comprises a combination of electroless nickel immersion gold (ENIG), copper, gold, or nickel. [Aspect 15] one or more magnetic pockets configured to hold the one or more magnetic objects; a top outer layer and a bottom outer layer, both of which include end lid manifolds to which the power silicon devices are attached; a first sealing gasket inside the upper outer layer, the first sealing gasket configured to seal around an upper side of the one or more magnetic pockets; a second sealing gasket inside the bottom outer layer, the second sealing gasket configured to seal around one or more magnetic leads of the one or more magnetic bodies; A cooling device comprising: [Aspect 16] a threaded interface that provides both an electrical connection between the one or more magnetic bodies and the first PCB and a mechanical connection that secures the first PCB to the cold plate. 16. The cooling device of embodiment 15, further comprising a magnetic interface comprising: [Aspect 17] 1. A method of assembling a magnetic lead of a cold plate, the method comprising: inserting one or more screw terminals into a fixture; placing the magnetic component within the fixture to position the one or more screw terminals against a top surface of the magnetic component; attaching one or more leads from the magnetic component to the one or more screw terminals; removing the magnetic component with the one or more leads attached from the fixture; placing a magnetic end cap over the magnetic component; screwing one or more cups to raise the one or more screw terminals to the same height; A method comprising: [Aspect 18] 18. The method of claim 17, further comprising positioning the magnetic component having one or more screw terminals at the same height within the cold plate using a hold-down fixture. [Aspect 19] 18. The method of embodiment 17, further comprising applying a varnish to one or more attachment points that attach the one or more leads to the one or more screw terminals. [Aspect 20] The method of claim 17, wherein the step of attaching one or more leads from the magnetic component to the one or more screw terminals includes either soldering or welding the one or more leads to the one or more screw terminals. [Explanation of symbols]

[0029] 1 Cold block, center block, center plate 2 End plate manifold, lid manifold 3 Gasket plate, sealing gasket 4 End Plate Manifold 5 Gasket plate, sealing gasket 6 Magnetic material 8 Magnetic material 9 Magnetic Reed 10 Multi-layer assembly, multi-layer cold plate 11 Common Mode Choke (CMC) 12 Common Mode Choke (CMC) 100 Common cold plate manifold (cold plate) 102 On-board charger (OBC), PCB parts 104 Entrance 106 Exit 108 Magnetic material 110 Energy Management Unit (EMU) 112 DC-DC PCB 300 Magnetic elements 302 Threaded Interface 304 thread interface 308 PCB 310 Cold Block 402 Magnetic screw terminal 404 Magnetic terminals, fixed screw terminals, hexagonal screw terminals 406 Magnetic cores, cold blocks, magnetic materials 408 Fastening screw 410 Thermal interface materials 412 Magnetic End Cap 600 Thread Interface 600' Thread Interface 600” thread interface 602 Screw terminal 604 Fixtures 606 Magnetic material 608 Solder joint 610 Magnetic End Cap 612 Cup

Claims

1. 1. An energy management unit (EMU), comprising: a cold plate sandwiched between a first printed circuit board (PCB) and a second PCB, the cold plate comprising one or more magnetic materials; A magnetic interface of the cold plate, the magnetic interface comprising: a threaded interface that provides both an electrical connection between the one or more magnetic bodies and the first PCB and a mechanical connection that secures the first PCB to the cold plate; A magnetic interface; Equipped with the cold plate is configured to cool both the first PCB and the second PCB; Energy Management Unit (EMU).

2. The EMU of claim 1 , wherein the first PCB comprises a DC-DC PCB and the second PCB comprises an on-board charger (OBC) PCB.

3. The EMU of claim 1 , wherein the cold plate comprises one or more magnetic pockets configured to hold the one or more magnetic bodies.

4. The cold plate is a top outer layer and a bottom outer layer; The EMU of claim 3 comprising multiple layers.

5. The EMU of claim 4 , wherein the cold plate further comprises a first sealing gasket inside the top outer layer and a second sealing gasket inside the bottom outer layer.

6. The EMU of claim 5 , wherein the first sealing gasket comprises an O-ring gasket.

7. The EMU of claim 5 , wherein the second sealing gasket comprises a gasket plate having asymmetric sealing surfaces on both sides.

8. The EMU of claim 5 , wherein the first sealing gasket is configured to seal around an upper side of the one or more magnetic pockets.

9. The EMU of claim 5 , wherein the second sealing gasket is configured to seal around one or more magnetic reeds of the one or more magnetic bodies.

10. 10. The EMU of claim 9, wherein the second sealing gasket is configured to allow coolant to flow over the one or more magnetic bodies and directly beneath a bottom of a field effect transistor (FET) mounted outside the bottom outer layer.

11. The EMU of claim 9 , wherein the second sealing gasket is configured to route coolant between the inside and outside of the bottom outer layer as the coolant passes through the cold plate.

12. The EMU of claim 1 , further comprising an end cap on top of the one or more magnetic bodies.

13. The EMU of claim 1 , wherein the threaded interface includes a compatible material interface with the first PCB.

14. The EMU of claim 13 , wherein the compatible material interface comprises a combination of electroless nickel immersion gold (ENIG), copper, gold, or nickel.

15. One or more magnetic pockets configured to hold one or more magnetic objects; a top outer layer and a bottom outer layer; a first sealing gasket inside the upper outer layer, the first sealing gasket configured to seal around an upper side of the one or more magnetic pockets; a second sealing gasket inside the bottom outer layer, the second sealing gasket configured to seal around one or more magnetic leads of the one or more magnetic bodies; A magnetic interface for a cold plate, the magnetic interface comprising: a threaded interface that provides both an electrical connection between the one or more magnetic bodies and a first printed circuit board (PCB) and a mechanical connection that secures the first PCB to the cold plate; A magnetic interface; A cooling device comprising:

16. 1. A method of assembling a magnetic lead of a cold plate, the method comprising: inserting one or more screw terminals into a fixture; placing the magnetic component within the fixture to position the one or more screw terminals against a top surface of the magnetic component; attaching one or more leads from the magnetic component to the one or more screw terminals; removing the magnetic component with the one or more leads attached from the fixture; placing a magnetic end cap over the magnetic component; screwing one or more cups to raise the one or more screw terminals to the same height; A method comprising:

17. 17. The method of claim 16, further comprising the step of placing the magnetic component having one or more screw terminals at the same height into the cold plate using a hold-down fixture.

18. 17. The method of claim 16, further comprising the step of applying a varnish to one or more attachment points that attach the one or more leads to the one or more screw terminals.

19. 17. The method of claim 16, wherein attaching one or more leads from the magnetic component to the one or more screw terminals comprises either soldering or welding the one or more leads to the one or more screw terminals.

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