Cold plate for power electronics systems

Abstract

This invention relates to a cold plate for power electronic systems. An energy management unit (EMU) is disclosed. The EMU includes a cold plate sandwiched between a first printed circuit board (PCB) and a second PCB, the cold plate including one or more magnetic elements; wherein the cold plate is configured to cool both the first PCB and the second PCB.

Description

Technical Field

[0001] This invention relates to on-board chargers (OBC) and DC-DC converters for electric vehicles, and more particularly to magnetic element mechanical and thermal interfaces for power electronic components. Background Technology

[0002] In automotive applications, power magnetic components are typically air-cooled or have a surface directly bonded to a liquid-cooled cold plate. Because the heat dissipation path is one-dimensional, such power electronic magnetic components are excessively large. Furthermore, typical magnetic components require complex soldering connections to subassemblies, including blade connectors, or direct soldering to the board.

[0003] High-power and high-density power supplies typically include a cold plate to which both power silicon and power magnetic components are mounted. After the power supply is assembled, approaching or removing the printed circuit board (PCB) to complete circuit testing is difficult, or in some cases, impossible. This is because the switching silicon devices are usually bolted (directly or via PCB mounting bolts) to the cold plate, while the magnetic components are encapsulated in the cold plate with thermally conductive material, and both components are directly soldered to the PCB. Summary of the Invention

[0004] One aspect of this disclosure relates to a shared cold plate manifold that cools two power electronic PCBs on each side, such as a DC-DC converter on one side and an OBC on the other side, which reduces the number of components, cost, and size of power electronic assemblies.

[0005] A second aspect of this disclosure relates to a cold plate manifold that allows low-pressure and high-flow-rate coolant to pass through, enabling the energy management unit (EMU) to be encapsulated within the battery cooling circuit and battery pack housing. This eliminates bulky connectors and housings, reducing weight, space, and cost while improving reliability.

[0006] A third aspect of this disclosure relates to a cold plate manifold that surrounds multiple magnetic elements and reliably cools and seals multiple (e.g., six) magnetic surfaces, thereby enabling better cooling and further miniaturizing energy storage or transmission devices.

[0007] The fourth aspect of this disclosure relates to a magnetic assembly including a threaded interface that facilitates assembly and allows for low-impedance contact between the magnetic element and the PCB, while providing a robust mechanical connection resistant to vibration and locally reacting the compressive stress of the thermal interface material to the magnetic screw. The magnetic screw terminal also serves as a standoff stud for the PCB.

[0008] The fifth aspect of this disclosure relates to a process for constructing a magnetic element with a threaded interface. Attached Figure Description

[0009] Figure 1 A perspective view of an exemplary energy management unit according to an embodiment of this disclosure is provided.

[0010] Figure 2 An exploded view of an exemplary cooling manifold according to an embodiment of this disclosure is provided.

[0011] Figure 3 Details of an exemplary magnetic component interface with a PCB according to an embodiment of this disclosure are shown.

[0012] Figures 4a and 4b provide embodiments according to this disclosure. Figure 3 Detailed illustration of the function of each specific feature of the magnetic threaded interface of the PCB.

[0013] Figure 5 Exemplary steps in the manufacturing process of a threaded interface according to an embodiment of this disclosure are shown.

[0014] Figures 6a and 6c illustrate embodiments according to this disclosure. Figure 5 Threaded interfaces at different stages of the manufacturing process. Detailed Implementation

[0015] In the following description of preferred embodiments, reference is made to the accompanying drawings, which form a part of this specification, and specific embodiments that can be practiced are illustrated in the drawings by way of illustration. It should be understood that other embodiments may be used and structural changes may be made without departing from the scope of embodiments of this disclosure.

[0016] Figure 1 An exemplary EMU 110 according to an embodiment of this disclosure is shown. EMU 110 includes a shared cold plate manifold (“cold plate”) 100 capable of cooling two power electronics PCBs on each side, such as a DC-DC PCB 112 on one side and an OBC 102 on the other. By fabricating the cold plate 100 in multiple layers, the coverage area of ​​the magnetic component 108 can overlap with the coverage areas of the power silicon and other PCB components 102. This is achieved by layering the cold plate 100 as follows: Figure 2 This is achieved using the multi-layered components shown.

[0017] like Figure 2As shown, the two outer layers 4, 2 of the multilayer assembly 10 contain end cap manifolds on which power silicon devices are mounted. Adjacent to the two inner components 3, 5 on either side are sealing gaskets. In the illustrated embodiment, the sealing gasket 5 can be a simple O-ring, while the sealing gasket 3 can be a gasket plate with asymmetrical sealing surfaces on both sides, which facilitates sealing outwards around the magnetic lead 9 while allowing coolant to flow around the lead above the magnetic element. It should be understood that other types of sealing gaskets may be used depending on the sealing requirements.

[0018] The inner side of the gasket 5 seals the top side of the magnetic bag surrounding the cold block (or center block) 1, while the outer side seals the magnetic leads 9 of the end plate manifold 2. The gasket 3 allows coolant ( Figure 2 (Not shown) Coolant flows above the top of magnetic components 6 and 8, while common-mode chokes (CMCs) 11 and 12 allow coolant to flow directly below the bottom of the field-effect transistor (FET) packaged outside the cover manifold 2. The liner plate 3 guides coolant into and out of the cover manifold 2 as it passes through the center plate 1. The final layer of the cold plate is the center block 1. Magnetic components 6 and 8 and CMCs 11 and 12 are encapsulated within the center plate. This multi-layered cold plate 10 achieves higher packaging and power density.

[0019] Refer again Figure 1 It will also be noted that the large inlet 104 and outlet 106 support a low-pressure and high-capacity coolant flow. In embodiments of this disclosure, the magnetic element 108 is immersed and cooled on all surfaces, including the outer edge, as well as the top and bottom. Additionally, a manifold with a sealing gasket (e.g.) Figure 2 The manifold shown allows for high flow rates. This combination of features enables the magnetic element 108 to be reduced in size.

[0020] Using conventional manufacturing processes for similar sealing gaskets used in automatic transmissions can keep manufacturing costs low. For example... Figure 2 The gaskets 3 and 5 shown maintain a high-pressure seal for complex cooling channels. The exemplary energy management unit disclosed in these embodiments allows for ultra-high flow rates (up to approximately 30 LPM), thereby allowing the EMU coolant to be connected in series with the battery pack. This provides an advantage when the EMU is encapsulated within the battery pack housing.

[0021] Figure 3Details of an exemplary magnetic element interface between the multilayer assembly 10 and the PCB are shown. In this embodiment, for the convenience of assembly 310, the magnetic element is fitted with a threaded interface 302 to allow for a screw interface 304. The threaded interface and the screw interface can form both an electrical connection between the magnetic element 300 and the PCB 308, and a mechanical connection to secure the PCB 308 to the coolant block 310. This mechanical interface can replace conventional riveting studs and can also provide a localized means to achieve compressive force on the thermal interface spacer material used under power silicon devices.

[0022] Figures 4a and 4b provide exemplary magnet thread interfaces for magnetic components to a PCB. Figure 3 Detailed illustration of 302 in Figure 4. As shown in Figures 4a and 4b, a retaining thread (screw) terminal 404 is used to facilitate easy assembly of the PCB to and removal from the magnetic terminal 404 of the magnetic component (without solder). The magnetic terminal 404 can also be used to secure the PCB (not shown in Figure 4) to the cold plate when the magnetic component 406 is deeply embedded (encapsulated) in the cold plate. When the magnetic screw terminal 402 is also used as a mounting location for the PCB, the fastening screws 408 for the power silicon can also be removed, and the PCB can be preloaded onto the thermal interface material 410 beneath the power silicon package to hold them in place. This is all achieved using the ABS plastic magnetic end cap 412 shown in Figure 4.

[0023] The end cap 412 is located on top of the magnetic core 406 and is formed by the base plate ( Figure 2 2) It is held in place. Furthermore, the screw terminal 404 can be plated to have a PCB-compatible material interface. This compatible material interface can include any combination of electroless nickel-gold (ENIG), copper, gold, or nickel. The magnetic end cap achieves all these functions through the specific geometry shown in Figure 4. Specifically, in this embodiment, the hexagonal screw terminal 404 can transmit screw torque to the plastic end cap 412 through the hexagonal geometry at the base. The end cap 412 can then transmit torque to the coolant block 406 through the external geometry of its outer edge.

[0024] Figure 5 This is a flowchart illustrating exemplary steps in the manufacturing process of a threaded interface according to embodiments of the present disclosure. Specifically, Figure 5The process of assembling magnetic leads is illustrated. First, screw terminals are inserted into the retaining device (step 501). Then, the magnetic component is placed into the retaining device, and the retaining device positions all screw terminals relative to the top surface of the magnetic core (step 502). The leads emerging from the magnetic component are then brazed or soldered to the screw terminals (step 503). The assembly is then removed from the retaining device, and optionally, varnish is applied to the solder joints (step 504). Magnetic end caps are installed, and cup-shaped fittings are screwed on to pull all screw terminals to the same height before the potting process (step 505). Finally, the assembly is placed in a cold block using the clamping retaining device, and heat potting is applied (step 506). It should be understood that... Figure 5 Some of the steps shown can be performed in parallel or in a different order to achieve the same result.

[0025] Figure 6a shows the execution Figure 5 Following steps 501 to 504, a threaded interface 600 is manufactured in part of the fixing device 604. Screw terminals (collectively referred to as 602) have been inserted into the fixing device 604. A magnetic element 606 has been placed in the fixing device 604 and secured with bolts. The fixing device 604 positions all screw terminals 602 relative to the top surface of the plane. Leads exiting the magnetic element are brazed or soldered to the screw terminals 602.

[0026] Figure 6b illustrates the execution Figure 5 The threaded interface 600' is further assembled after step 505. The partially assembled threaded interface 600' has been removed from the fixture, and varnish has optionally been applied to the weld joint (collectively referred to as 608).

[0027] Figure 6c shows that in Figure 5 During step 506, the threaded interface 600” is installed. The magnetic end cap 610 is installed and the cup-shaped piece 612 is screwed on to pull all screw terminals to the same height before the potting process. Then, the threaded interface 600” is placed in the cold block (not shown in Figure 6c).

[0028] While 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 to be included within the scope of the embodiments of the present disclosure as defined by the appended claims.

Claims

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 elements; The magnetic component interface of the cold plate includes: A threaded interface, which serves simultaneously as an electrical connection between the one or more magnetic components and the first PCB, and a mechanical connection between the first PCB and the cold plate; The cold plate is configured to cool both the first PCB and the second PCB.

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

3. The EMU according to claim 1, wherein, The cold plate includes one or more magnetic bags configured to hold the one or more magnetic elements.

4. The EMU according to claim 3, wherein, The cold plate comprises multiple layers, the multiple layers including: The top outer layer and the bottom outer layer each include an end cap manifold to which power silicon devices are mounted.

5. The EMU according to claim 4, wherein, The cold plate also includes a first sealing gasket inside the top outer layer and a second sealing gasket inside the bottom outer layer.

6. The EMU according to claim 5, wherein, The first sealing gasket includes an O-ring gasket.

7. The EMU according to claim 5, wherein, The second sealing gasket includes a gasket plate having asymmetrical sealing surfaces on both sides.

8. The EMU according to claim 5, wherein, The first sealing gasket is configured to seal around the top side of the one or more magnetic bags.

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

10. The EMU according to claim 9, wherein, The second sealing gasket is configured to allow coolant to flow over the one or more magnetic elements and directly below the bottom of the externally packaged field-effect transistor FET in the bottom outer layer.

11. The EMU according to claim 9, wherein, The second sealing gasket is configured to introduce and exit the coolant into the bottom outer layer as the coolant passes through the cold plate.

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

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

14. The EMU according to claim 13, wherein, The compatible material interface includes electroless nickel-gold (ENIG), copper, gold, or a combination of nickel.

15. A cooling device, comprising: One or more magnetic bags configured to hold one or more magnetic elements; A magnetic component interface, comprising: a threaded interface, which serves simultaneously as an electrical connection between the one or more magnetic components and a first PCB, and a mechanical connection between the first PCB and a cold plate; A top outer layer and a bottom outer layer, both of which include end cap manifolds to which power silicon devices are mounted; A first sealing gasket inside the top outer layer is configured to seal around the top side of the one or more magnetic pouches; and The second sealing gasket inside the bottom outer layer is configured to seal around one or more magnetic leads of the one or more magnetic elements.

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