Power device heat dissipation structure for vehicle-mounted OBC or vehicle-mounted DC-DC converter

Abstract

The utility model relates to the field of pure electric and hybrid electric vehicle charging technology and voltage conversion equipment, in particular to a power device heat dissipation structure for a vehicle-mounted OBC (On Board Carrier) or a vehicle-mounted DC-DC (Direct Current-Direct Current) converter. A power device heat dissipation structure for a vehicle-mounted OBC or a vehicle-mounted DC-DC converter comprises a heat dissipation shell, a PCB and a shell cover plate, the PCB is provided with a plurality of power devices, a heat dissipation boss extending upwards is arranged in the heat dissipation shell, the PCB is provided with a plurality of windows penetrating up and down, heat dissipation blocks are fixed at the windows of the PCB, and the heat dissipation blocks are provided with heat dissipation holes. The power device is arranged on the upper side of the PCB, part of the power device extends to the position above the window and the heat dissipation block, the heat dissipation block is supported above the heat dissipation boss and limited between the power device and the heat dissipation boss, an elastic block is placed above the PCB, and the elastic block is limited between the power device and the shell cover plate. The utility model has the advantages of simple structure, convenience in assembly and higher use reliability.

Description

Technical Field

[0001] This utility model relates to the field of charging technology and voltage conversion equipment for pure electric and hybrid vehicles, and specifically to a heat dissipation structure for power devices used in on-board OBC or on-board DC-DC converters. Background Technology

[0002] With the rapid development of new energy vehicles, on-board chargers (OBCs) and on-board DC-DC converters, as core components, are experiencing continuous increases in power density. Conventional on-board chargers and on-board DC-DC converters include a liquid-coolable housing. Power devices (such as MOSFETs and IGBTs) generate significant heat during operation, requiring adequate heat dissipation to ensure reliability and lifespan. Currently, a flexible metal strip structure is commonly used, such as the heat dissipation structure disclosed in patent application CN222981893U. This structure relies on the elasticity of the strip to tightly adhere the power devices to the side of the heat dissipation protrusions on the housing, achieving heat conduction.

[0003] The above scheme has the following defects: (1) The elastic pressure strip has a complex structure and high processing requirements: the pressure strip needs to be precisely stamped and formed, the mating surface angle and elastic coefficient are difficult to control, and the mold cost is high; (2) The mechanical stress on the power device is large and difficult to control: the elastic pressure acts directly on the surface of the power device, the stress concentration is easy to cause damage to the power device, and the elastic force decays over time, resulting in poor long-term reliability; (3) The assembly process is complex. It is necessary to first fix the frame-type pressure strip in the heat sink housing, then place the power device on the pressure strip frame, complete the alignment of the power device pins with the mounting holes of the PCB board, and then weld the power device; (4) There are many parts and the material cost is high. Utility Model Content

[0004] The purpose of this invention is to provide a heat dissipation structure for power devices used in vehicle-mounted OBCs or vehicle-mounted DC-DC converters that is simple in structure, highly reliable, and easy to assemble.

[0005] To achieve the above objectives, this utility model employs a heat dissipation structure for power devices in a vehicle-mounted OBC or vehicle-mounted DC-DC converter, comprising an upwardly opening heat dissipation housing, a PCB board placed inside the heat dissipation housing, and a housing cover plate placed inside the heat dissipation housing. The PCB board is provided with a plurality of power devices. The housing cover plate is located above the PCB board and the power devices. The heat dissipation housing has upwardly extending heat dissipation protrusions. The PCB board has a plurality of vertically penetrating windows, and heat dissipation blocks are fixed at the windows of the PCB board. The power devices are disposed on the upper side of the PCB board, with a portion extending above the windows and heat dissipation blocks. The heat dissipation blocks are supported on the heat dissipation protrusions and confined between the power devices and the heat dissipation protrusions. An elastic block is placed above the PCB board, and the elastic block is confined between the power devices and the housing cover plate.

[0006] This invention replaces the traditional frame-type elastic pressure strip with a heat sink and an elastic block. The heat sink can be a copper block that has only undergone simple machining, and the elastic block can preferably be a sheared thermally conductive silicone rubber, foam, etc. The processing requirements are low, no mold is required, and the production cost and material management cost of the parts are lower.

[0007] After assembly, pressure is transmitted through the vertical path of the elastic block, power device, heat sink, and heat dissipation boss. The heat sink can effectively contact the end face of the power device, making the pressure distribution more uniform and avoiding stress concentration. The power device is directly soldered and fixed to the PCB board, eliminating the need for traditional elastic pressure strips to press and position the power device for alignment of the power device pins with the mounting holes on the PCB board. The elastic pressure that the power device has to withstand is smaller. At the same time, there is a wider range of elastic block options. Through the above-mentioned measures, stress concentration at the power device is avoided, damage to the power device is prevented, and reliability during long-term use is guaranteed.

[0008] When assembling the vehicle-mounted OBC of this utility model, the power devices are first soldered onto the PCB board, then the heat sink is positioned at the heat dissipation boss and the PCB board is covered. Next, the PCB board and the heat sink housing are fixed, and then the elastic block is placed and the housing cover is secured. The soldering of the power devices to the PCB board can be completed before assembly, eliminating the need for alignment within the heat sink housing, significantly simplifying the assembly process.

[0009] Preferably, the heat sink includes a body and a laterally extending extension, the extension being confined between the PCB board and the heat dissipation boss, with the body located at the window. This structure allows the heat sink to both contact the power device within the window and achieve mechanical support and positioning through the extension.

[0010] Preferably, the inner wall of the window is plated with a copper layer. The heat sink and the copper layer are preferably fitted with a gap, but contact is also possible. The copper layer enhances current carrying capacity and thermal conductivity.

[0011] Preferably, the heat sink is fixed to the PCB board via a surface mount device. The heat sink can be soldered onto the PCB board as a standard component along with the power device, further reducing assembly steps and thus improving production efficiency.

[0012] Preferably, an insulating sheet is laid flat on the heat dissipation protrusion, and the heat dissipation block is supported on the insulating sheet. The insulating sheet can preferably be made of thermally conductive insulating material (such as silicone pads, ceramic sheets, etc.) to ensure thermal conductivity efficiency while achieving electrical isolation.

[0013] Preferably, the top surface of the heat sink is located above the top surface of the PCB board. This design ensures a stable pressure contact between the heat sink and the power device, resulting in lower thermal resistance and preventing excessive bending of the power device leads.

[0014] Preferably, each elastic block corresponds to multiple power devices, and the elastic block is elongated. This eliminates the need for a one-to-one correspondence between elastic blocks and power devices, further reducing the amount of materials required during assembly. Simultaneously, multiple power devices can be covered and pressed together in a single operation, eliminating the need to repeatedly place multiple small elastic blocks, significantly reducing assembly time and the probability of errors. Furthermore, the elongated shape of the elastic block allows for more uniform pressure distribution.

[0015] This utility model has the advantages of simple structure, easy assembly, and higher reliability. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the power device of this utility model.

[0017] Figure 2 This is a structural diagram of the present invention without the housing cover plate assembled.

[0018] Figure 3 This is a schematic diagram of the structure of the heat dissipation shell of this utility model. Detailed Implementation

[0019] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0020] like Figures 1 to 3As shown, this embodiment discloses a heat dissipation structure for power devices used in vehicle-mounted OBCs or vehicle-mounted DC-DC converters. It includes an upward-opening heat dissipation housing 1, a PCB board 2 placed inside the heat dissipation housing, and a housing cover plate (not shown) located at the upper opening of the heat dissipation housing. The heat dissipation housing 1 has an upward-extending heat dissipation boss 11, on which an insulating sheet 12 is laid. The heat dissipation boss 11 supports a heat sink 4 and the PCB board 2, on which the heat sink 4 and power devices 3 are fixed. An elastic block 5 is placed above the PCB board 2, clamping and restricting the power devices 3 between the upper and lower parts of the housing cover plate (not shown). The heat sink 4 is a copper block, and the insulating sheet 12 is made of silicone pads or ceramic sheets. The elastic blocks 5 are elongated, with each elastic block 5 corresponding to multiple power devices 3.

[0021] The PCB board 2 has several vertically penetrating windows 20. Power devices 3 are fixed to the upper side of the PCB board 2 and adjacent to the windows 20, with a portion of the power devices 3 extending above the windows. The heat sink 4 includes a body 41 and a laterally extending extension 42. The extension 42 is fixed to the PCB board 2 via a patch, and the body 41 is located at the windows 20. When the PCB board 2 is placed above the heat dissipation boss 11, the extension 42 is confined between the PCB board 2 and the insulating sheet 12. The top surface of the body 41 of the heat sink 4 is located above the upper surface of the PCB board 2 and contacts the power devices 3. The multiple windows 20 on the PCB board 2 are arranged at intervals along the extending direction of the heat dissipation boss 11, and the inner walls of the windows 20 are plated with a copper layer.

[0022] This embodiment ensures effective heat dissipation contact of power devices through a vertical clamping structure, eliminating the need to place power devices on the side of the heat dissipation boss. While simplifying the design and reducing costs, it significantly improves heat dissipation performance, assembly efficiency, and long-term reliability, overcoming the problems of complex elastic pressure strip structures, stress concentration, and assembly difficulties in traditional elastic pressure strip structures.

Claims

1. A power device heat dissipation structure for an on-board OBC or on-board DC-DC converter, comprising an upwardly open heat dissipation housing, a PCB board placed in the heat dissipation housing, and a housing cover plate located at the upper opening of the heat dissipation housing, wherein the PCB board is provided with a plurality of power devices, and the housing cover plate is located on the upper side of the PCB board and the power devices, characterized in that: The heat dissipation housing has a heat dissipation boss extending upward, the PCB is provided with a plurality of windows penetrating from top to bottom, the heat dissipation block is fixed at the window of the PCB, the power device is arranged on the upper side of the PCB, the power device extends partially above the window and the heat dissipation block, the heat dissipation block is supported on the heat dissipation boss and is limited between the power device and the heat dissipation boss, the elastic block is placed above the PCB and is limited between the power device and the housing cover plate. ​ 2. The power device heat dissipation structure for an on-board OBC or on-board DC-DC converter according to claim 1, characterized by: The heat dissipation block comprises a body and an extension extending laterally, the extension is limited between the PCB and the heat dissipation boss, and the body is located at the window.

3. The power device heat dissipation structure for an on-board OBC or on-board DC-DC converter according to claim 1, characterized by: A copper layer is plated on the inner wall of the window.

4. The power device heat dissipation structure for an on-board OBC or on-board DC-DC converter according to claim 1 or 2, characterized by: The heat dissipation block is fixed on the PCB in the form of a patch.

5. The power device heat dissipation structure for an on-board OBC or on-board DC-DC converter according to claim 1, characterized by: An insulating sheet is laid on the heat dissipation boss, and the heat dissipation block is supported on the insulating sheet.

6. The power device heat dissipation structure for an on-board OBC or on-board DC-DC converter according to claim 1, characterized by: The top surface of the heat dissipation block is located above the upper end surface of the PCB.

7. The power device heat dissipation structure for an on-board OBC or on-board DC-DC converter according to claim 1, characterized by: Each elastic block corresponds to a plurality of power devices, and the elastic block is in the shape of a long strip.

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