Power module heat dissipation structure

Abstract

The invention discloses a heat dissipation structure of a power module, belongs to the technical field of heat dissipation of the power module, aims at achieving efficient heat dissipation and improving the output performance of the power module on the basis of achieving miniaturization of the power module, and provides a heat dissipation structure based on a PCB, the power module based on the heat dissipation structure and an inverter system based on the heat dissipation structure. The integrated inverter system in a full-PCB mode can be achieved, the compact type is high, heat dissipation of the power chip is good, three-dimensional packaging of the inverter system and the power chip is achieved through device embedding type design, loop inductance is effectively reduced through lamination design of the PCB, the electric stress in system operation is reduced, the safety and reliability of operation are improved, and the reliability of the inverter system is improved. Meanwhile, the improvement design of the system performance is also facilitated; meanwhile, the designed heat dissipation structure based on the PCB is different from a traditional metal heat dissipation structure, and a driving circuit and a control circuit in the inverter system can stretch across the structure for heat dissipation.

Description

Technical Field

[0001] The invention belongs to the technical field of power module heat dissipation, in particular to a power module heat dissipation structure. Background Art

[0002] The power module is a core key component in the electric drive system of electric vehicles. It is responsible for the high-power electrical energy conversion in electric vehicles. It has a decisive influence on the performance, efficiency, cost, safety and reliability of the electric drive system and even the entire vehicle. The main factors affecting the characteristics of the power module are structure, process, materials, etc. Most innovations and inventions for power modules revolve around these aspects.

[0003] Automotive power modules are affected by vehicle applications, and high requirements are placed on module miniaturization, high-performance output, efficient heat dissipation, and high reliability. Existing power module inventions are mostly designed from the above dimensions for optimization and improvement, such as: improving module heat dissipation efficiency through single-sided or double-sided direct water cooling, and achieving high reliability through ultrasonic bonding of power terminals. However, the above inventions all belong to planar solutions, with a planar layout of power chips. By optimizing the radiator design, such as direct water cooling, PinFins of different shapes, and double-sided cooling, efficient heat dissipation and performance improvement can be achieved, or by optimizing the busbar layout, such as stacked busbars, low parasitic inductance can be achieved, and performance and reliability can be improved. The planar layout of the power module is affected by the planar layout of the power chip, and it is difficult to achieve miniaturization. At the same time, the planar layout makes it impossible to achieve a stacked design for the internal wiring, and it can only be stacked through the external power copper busbar, and the optimization of parasitic inductance is limited. Summary of the invention

[0004] The technical solution of the present invention is as follows: a power module heat dissipation structure, including: a power module with an integrated control circuit and a DC bus capacitor, the power module is composed of a control circuit, a middle layer heat sink, a drive circuit, a power chip and a bottom heat sink from top to bottom.

[0005] The control circuit transmits signals to the drive circuit across layers through control signal vias, and exchanges signals in the control signal routing layer. The drive circuit connects the drive signal routing layer to the control electrode of the power chip through drive signal vias to control the operation of the power chip. The power current via is connected to the output electrode of the power chip, and then connected to the load through the power current routing layer.

[0006] The bottom heat sink and the controller box form a cooling loop to provide heat dissipation for the bottom of the power chip. The middle heat sink can isolate the influence of the power chip heating on the control circuit, and also dissipate heat for the drive circuit and the top of the power chip.

[0007] Furthermore, the basic structure of the middle layer radiator includes a top layer, a middle layer and a bottom layer, and the middle layer is filled with a cooling medium.

[0008] Furthermore, the top layer and the bottom layer are at least two layers of copper, and the top layer of copper and the bottom layer of copper are connected through copper-plated vias.

[0009] Furthermore, the copper-plated vias are blind holes or plugged holes to ensure the internal sealing of the heat sink.

[0010] Furthermore, the surfaces of the bottom copper sheet on the top layer and the top copper sheet on the bottom layer are capillary structures.

[0011] Furthermore, the power chip is an IGBT, a diode or a MOSFET device.

[0012] Furthermore, the power current vias are plugged with copper paste.

[0013] The beneficial effects of the present invention are:

[0014] The purpose of the present invention is to achieve efficient heat dissipation and improve the output performance of the power module on the basis of miniaturization of the power module. The present invention proposes a heat dissipation structure based on PCB, as well as a power module and an inverter system based on the structure. The invention can realize an integrated inverter system in the form of a full PCB board, which is compact and has good heat dissipation of the power chip. The three-dimensional packaging of the inverter system and the power chip is realized through the embedded device design. The stacking design realized by PCB effectively reduces the loop inductance, reduces the electrical stress in the system operation, improves the safety and reliability of the operation, and is also conducive to the improvement of the system performance design; at the same time, the designed heat dissipation structure based on PCB is different from the traditional metal heat dissipation structure, and can also enable the drive and control circuits in the inverter system to dissipate heat across the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the inverter system of the present invention.

[0016] Figure 2 Schematic diagram of the power module of the present invention.

[0017] Figure 3 It is a schematic diagram of the intermediate radiator of the present invention.

[0018] Figure 4 It is a schematic diagram of the internal cooling circuit of the intermediate radiator of the present invention.

[0019] Figure 5 It is a schematic diagram of the capillary structure on the inner surface of the intermediate heat sink of the present invention.

[0020] In the figure:

[0021] 1 control circuit, 2 middle layer heat sink, 3 drive circuit, 4 power chip, 5 bottom heat sink, 101 control signal via, 102 control signal routing layer, 301 drive signal via, 302 drive signal routing layer, 401 power current via, 402 power current routing layer, 201 top layer, 202 middle layer, 203 bottom layer, 204 top copper sheet, 205 bottom copper sheet, 206 copper-plated via, 207 cooling medium, 208 capillary structure. DETAILED DESCRIPTION

[0022] It should be noted that in the description of the present invention, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect" and the like should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral connection; the connection can be a mechanical connection or an electrical connection; the connection can be a direct connection or an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] A power module heat dissipation structure consists of a power module integrated with a control circuit and a DC bus capacitor.

[0025] The power module is a multi-layer PCB structure, which is composed of a control circuit 1, a middle layer heat sink 2, a drive circuit 3, a power chip 4 and a bottom heat sink 5 stacked from top to bottom.

[0026] The power chip 4 may use devices such as IGBT, diode, MOSFET, etc.;

[0027] The driving circuit 3 includes a driving signal and its peripheral circuits. The control circuit 1 transmits signals to the driving circuit 3 across layers through the control signal via 101, and at the same time interacts with the signal in the control signal routing layer 102. The driving circuit 3 is connected to the control electrode of the power chip 4 through the driving signal via 301, the driving signal routing layer 302, to control the operation of the power chip 4. The power current via 401 is connected to the output electrode of the power chip 4, such as the collector or emitter of the IGBT, the drain or source of the MOSFET, and then connected to the load, such as a motor or inductor, through the power current routing layer 402.

[0028] The power current via 401 needs to bear a large current, and copper paste needs to be used to plug the via to improve its current carrying capacity. The bottom heat sink 5 forms a cooling loop with the controller box to provide heat dissipation for the bottom of the power chip 4. The middle layer heat sink 2 can isolate the influence of the heat generated by the power chip 4 on the control circuit 1, and also dissipate heat for the drive circuit 3 and the top of the power chip 4.

[0029] The basic structure of the intermediate layer heat sink 2 includes a top layer 201, an intermediate layer 202 and a bottom layer 203, wherein the top layer 201 and the bottom layer 203 are at least two layers of copper, namely, a top layer of copper 204 and a bottom layer of copper 205, and the top layer of copper 204 and the bottom layer of copper 205 are connected by a copper-plated via 206 to reduce the thermal resistance between the inner and outer layers and improve the heat dissipation effect. The vias are blind holes or plug holes to ensure the internal sealing of the heat sink. The interior of the intermediate layer 202 is as follows Figure 4 As shown in the example, the cooling structure inside the middle layer heat sink 2 is determined, and the cooling medium 207 is filled in the middle layer cooling structure.

[0030] The control signal via 101 spanning the top layer 201 , the middle layer 202 , and the bottom layer 203 can realize signal transmission between the top control circuit 1 and the driving circuit 3 .

[0031] Figure 4 This is an example of the internal cooling circuit of the middle layer radiator 2. Only a few cooling circuit structure examples are given here. In practice, a variety of structures can be used to achieve heat dissipation. The cooling circuit is filled with cooling medium.

[0032] Figure 5 The capillary structure 208 is formed on the copper surface of the bottom layer 201 of the middle layer heat sink 2 and the top layer 203 of the bottom layer. A grooved capillary structure is formed on the copper surface of the lower part of the first circuit board by physical scratching or chemical etching to promote the reflux of the working fluid and enhance the heat conduction effect of the heat spreader.

[0033] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. A power module heat dissipation structure, characterized in that: include: The power module and DC bus capacitor of the integrated control circuit are composed of the control circuit, the middle layer heat sink, the drive circuit, the power chip and the bottom heat sink from top to bottom. The control circuit transmits signals with the drive circuit through the control signal vias across the layers, and at the same time, the signals are exchanged in the control signal routing layer. The drive circuit is connected to the control electrode of the power chip through the drive signal vias to connect the drive signal routing layer to the control electrode of the power chip to control the operation of the power chip. The power current vias are connected to the output electrode of the power chip, and then connected to the load through the power current routing layer. The bottom heat sink and the controller box form a cooling loop to provide heat dissipation for the bottom of the power chip. The middle layer heat sink can isolate the influence of the heat of the power chip on the control circuit, and also dissipate heat for the drive circuit and the top of the power chip.

2. A power module heat dissipation structure according to claim 1, characterized in that: The basic structure of the intermediate layer radiator includes a top layer, an intermediate layer and a bottom layer, and the intermediate layer is filled with a cooling medium.

3. A power module heat dissipation structure according to claim 2, characterized in that: The top and bottom layers are at least 2 layers of copper, and the top copper layer and the bottom copper layer are connected by copper-plated vias.

4. A power module heat dissipation structure according to claim 3, characterized in that: Copper-plated vias use blind holes or plugged holes to ensure the internal sealing of the heat sink.

5. A power module heat dissipation structure according to claim 3, characterized in that: The surfaces of the bottom copper skin on the top layer and the top copper skin on the bottom layer are capillary structures.

6. A power module heat dissipation structure according to claim 1, characterized in that: The power chip is an IGBT, diode or MOSFET device.

7. The power module heat dissipation structure according to claim 1, characterized in that: Power current vias are plugged with copper paste.

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