Power module and vehicle

Abstract

The application provides a power module and a vehicle. It relates to the technical field of semiconductors. The power module comprises a power component, a heat sink and a first welding layer. The power component comprises an insulating substrate, a power chip and a second heat-conducting layer. The power chip and the second heat-conducting layer are arranged on opposite sides of the insulating substrate. The heat sink comprises a heat sink main body and a first heat-conducting layer. The first heat-conducting layer is arranged on the heat sink. The first welding layer is connected between the second heat-conducting layer and the first heat-conducting layer. In the arrangement direction from the first heat-conducting layer to the second heat-conducting layer, the orthographic projection of the first welding layer on the second heat-conducting layer is located within the boundary of the second heat-conducting layer. In this way, the second heat-conducting layer is only partially connected with the first welding layer. The position of the second heat-conducting layer where the first welding layer is not laid is more prone to deformation. Part of the stress generated by the power component will be transferred from the insulating substrate of the power module to the second heat-conducting layer, thereby reducing the stress applied to the insulating substrate by the power component.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more particularly to a power module and a vehicle. Background Technology

[0002] Post-soldering is a new type of surface mount technology (SMT). It involves pre-applying a paste-like additive to electronic devices before they are placed in a high-temperature formic acid reflow oven, hot air reflow oven, or vapor phase reflow oven for soldering. Post-soldering is a growing trend in power modules to meet the increasing power density requirements of power modules.

[0003] In related technologies, after the power component and the heat sink are welded, stress will be generated inside the power component when it is heated and expands during operation or when it is cooled and contracted from the working state to the non-working state. As the power component is repeatedly operated, the stress generated by the power component will gradually damage the substrate of the power component. Utility Model Content

[0004] This application provides a power module and a vehicle. The purpose is to improve the reliability of the power module.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a power module that can be applied to a vehicle, such as a hybrid vehicle or a pure electric vehicle.

[0007] The power module provided in this application includes a heat sink, a power component, and a first solder layer. The heat sink includes a heat dissipation body and a first thermally conductive layer, with the first thermally conductive layer disposed on the heat sink. The power component includes an insulating substrate, a power chip, and a second thermally conductive layer, with the power chip and the second thermally conductive layer disposed on opposite sides of the insulating substrate. The first solder layer connects the first thermally conductive layer and the second thermally conductive layer. Along the arrangement direction from the first thermally conductive layer to the second thermally conductive layer, the orthographic projection of the first solder layer onto the second thermally conductive layer is located within the boundary of the second thermally conductive layer.

[0008] In the power module provided in this application embodiment, the molten solder from the subsequent soldering of the power component and the heat sink spreads through the gap between the first and second thermally conductive layers. After cooling, the molten solder forms the first solder layer. Since the orthogonal projection of the first solder layer onto the second thermally conductive layer is located within the boundary of the second thermally conductive layer, meaning the second thermally conductive layer is only partially connected to the first solder layer, the area of ​​the second thermally conductive layer where the first solder layer is not laid will be more prone to deformation. Thus, part of the stress generated when the power component expands due to heat during operation or when it contracts due to cooling from an operating state to a non-operating state will be transferred from the insulating substrate of the power module to the area of ​​the second thermally conductive layer where the first solder layer is not laid. This reduces the stress exerted by the power component on the insulating substrate, reduces damage to the insulating substrate during operation, and thereby improves the reliability of the power module.

[0009] Meanwhile, this application reduces the contact area between the first welding layer and the second heat-conducting layer, as well as the contact area between the first welding layer and the first heat-conducting layer, thereby reducing the stress on the first welding layer after large-area welding, and reducing the probability of excessive stress on the first welding layer and cracking between the first heat-conducting layer and / or the second heat-conducting layer.

[0010] In one possible implementation, the power module further includes a solder resist layer disposed on the surface of the second thermally conductive layer facing the first thermally conductive layer and surrounding the periphery of the first solder layer.

[0011] In this example, when the molten solder spreads through the gap between the second thermally conductive layer and the first thermally conductive layer, if the molten solder spreads to the solder resist layer, the solder resist layer prevents the molten solder from continuing to spread from the second thermally conductive layer to the first thermally conductive layer, confining the molten solder within the area enclosed by the solder resist layer, ensuring that only a portion of the first solder layer is laid on the side of the second thermally conductive layer facing the first thermally conductive layer.

[0012] In one possible implementation, along the arrangement direction from the first thermally conductive layer to the second thermally conductive layer, the orthographic projection of the first thermally conductive layer onto the second thermally conductive layer lies within the boundary of the second thermally conductive layer; or...

[0013] Along the arrangement direction from the first thermal conductive layer to the second thermal conductive layer, the orthogonal projection of the first thermal conductive layer onto the first welding layer is located within the boundary of the first welding layer or coincides with the first welding layer.

[0014] In this example, the area of ​​the first thermally conductive layer facing the second thermally conductive layer is smaller than the area of ​​the second thermally conductive layer facing the first thermally conductive layer. When the molten solder spreads through the gap between the second and first thermally conductive layers, because the area of ​​the first thermally conductive layer facing the second thermally conductive layer is smaller than the area of ​​the second thermally conductive layer facing the first thermally conductive layer, the molten solder is difficult to continue spreading on the second thermally conductive layer after it has covered the first thermally conductive layer. This forms a first weld layer that covers the first thermally conductive layer but not the second thermally conductive layer, allowing the area of ​​the second thermally conductive layer where the first weld layer is not laid to deform and absorb the stress generated by the power component.

[0015] In one possible implementation, the first heat-conducting layer has a welding surface and at least one sidewall adjacent to the welding surface and arranged at an angle, the welding surface being connected to the first welding layer, and a first chamfer being provided at the junction of the welding surface and at least one of the sidewalls.

[0016] In this example, after setting the first chamfer at the connection between the welding surface and the sidewall, it is equivalent to cutting off part of the welding surface when processing the first chamfer, that is, reducing the area of ​​the welding surface. This makes the area of ​​the welding surface smaller than the area of ​​the second heat-conducting layer facing the first heat-conducting layer. When the power component and the heat sink are welded, the molten solder spreads in the gap between the welding surface and the second heat-conducting layer facing the first heat-conducting layer. After the molten solder covers the welding surface, it is difficult for it to continue to spread on the second heat-conducting layer facing the first heat-conducting layer. In this way, the orthogonal projection of the first welding layer formed by the solidified molten solder on the second heat-conducting layer is located within the boundary of the second heat-conducting layer.

[0017] In one possible implementation, the first weld layer is also connected to the first chamfer.

[0018] In this example, the connection between the first weld layer and the first chamfer not only increases the contact area between the first weld layer and the first thermally conductive layer, thus improving the heat exchange area between them and thereby enhancing the heat dissipation effect of the heat sink on the power components, but also does not increase the contact area between the first weld layer and the second thermally conductive layer.

[0019] In one possible implementation, there are multiple sidewalls, and at least two adjacent sidewalls among the multiple sidewalls have a second chamfer at the connection point.

[0020] In this example, when a second chamfer is set at the connection between adjacent sidewalls, a portion of the welding surface will also be cut. For example, when the welded part is rectangular, the first thermal conductive layer will cut the four corners of the welding surface after the second chamfer is set. In this way, the area of ​​the welding surface is further reduced. When the power component and the heat sink are welded, a smaller first welding layer can be formed between the first thermal conductive layer and the second thermal conductive layer. This further reduces the stress that the power component can apply to the insulating substrate, thereby further improving the reliability of the power component.

[0021] In one possible implementation, the first heat-conducting layer has a welding surface and a plurality of sidewalls adjacent to the welding surface and forming an angle, the welding surface being connected to the first welding layer, and a second chamfer being provided at the connection between at least two adjacent sidewalls of the plurality of sidewalls.

[0022] In this example, when a second chamfer is set at the connection between adjacent sidewalls, a portion of the welding surface will also be cut. For example, when the welded part is rectangular, the first thermal conductive layer will cut the four corners of the welding surface after the second chamfer is set. In this way, the area of ​​the welding surface is further reduced. When the power component and the heat sink are welded, a smaller first welding layer can be formed between the first thermal conductive layer and the second thermal conductive layer. This further reduces the stress that the power component can apply to the insulating substrate, thereby further improving the reliability of the power component.

[0023] In one possible implementation, the number of the second chamfers is multiple, and the multiple second chamfers are evenly distributed about the center point of the welding surface.

[0024] In this example, the equally spaced second chamfers can make the shape of the first weld layer more regular. Therefore, the external stress applied to the first heat-conducting layer after the first weld layer and the first heat-conducting layer are connected is more regular or uniform, and the external stress applied to the second heat-conducting layer after the first weld layer and the second heat-conducting layer are connected is also more regular or uniform. This can reduce the probability of cracking between the first weld layer and the first heat-conducting layer, as well as reduce the probability of cracking between the first weld layer and the second heat-conducting layer.

[0025] In one possible implementation, along the arrangement direction from the first thermally conductive layer to the second thermally conductive layer, the orthogonal projection of the first thermally conductive layer onto the power chip covers the power chip.

[0026] In this example, heat from the power chip must pass through the first thermally conductive layer to reach the heat sink. Along the arrangement direction from the first to the second thermally conductive layer, once the orthographic projection of the first thermally conductive layer onto the power chip covers it, the heat can be transferred to the heat sink via a shorter path. If, along the arrangement direction from the first to the second thermally conductive layer, the orthographic projection of the first thermally conductive layer onto the power chip does not cover it, the heat must move radially along the second thermally conductive layer on the insulating substrate located between the first and the power chip before it can reach the first thermally conductive layer.

[0027] Secondly, this application also provides a vehicle, the vehicle including a motor and a power module as described in any of the above implementations, the power module being electrically connected to the motor.

[0028] Since the vehicle provided in this application includes the aforementioned power module, and the second heat-conducting layer of the power module is only partially connected to the first welding layer, the area of ​​the second heat-conducting layer where the first welding layer is not laid is more prone to deformation. Thus, part of the stress generated by the power component during operation will be transferred from the insulating substrate of the power module to the second heat-conducting layer, thereby reducing the stress exerted by the power component on the insulating substrate and reducing damage to the insulating substrate, resulting in higher reliability. The vehicle of this application also has higher reliability. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of a power module according to an embodiment of this application;

[0030] Figure 2 This is a cross-sectional view of a power module according to another embodiment of this application;

[0031] Figure 3 This is a cross-sectional view of a power module according to another embodiment of this application;

[0032] Figure 4 This is a top view of a heat sink according to an embodiment of this application;

[0033] Figure 5 This is a top view of a heat sink according to another embodiment of this application;

[0034] Figure 6 This is a top view of a heat sink according to another embodiment of this application;

[0035] Figure 7 This is a top view of a heat sink according to another embodiment of this application;

[0036] Figure 8 This is a cross-sectional view of a power module according to another embodiment of this application;

[0037] Figure 9This is a cross-sectional view of a power module according to another embodiment of this application;

[0038] Figure 10 for Figure 1 Enlarged schematic diagram of the structure of section A in the middle.

[0039] Reference numerals: 10, power module; 12, heat sink; 121, heat dissipation body; 122, first thermally conductive layer; 1221, first chamfer; 1222, second chamfer; 11, power component; 111, insulating substrate; 112, power chip; 113, second thermally conductive layer; 114, third thermally conductive layer; 115, second solder layer; 116, outer shell; 13, first solder layer; 14, solder resist layer. Detailed Implementation

[0040] Post-soldering is a new type of surface mount technology. It involves pre-applying a paste-like additive to electronic devices before they are placed in a high-temperature formic acid reflow oven, hot air reflow oven, or vapor phase reflow oven for soldering. Post-soldering is a growing trend in power modules to meet the increasing power density requirements of power modules.

[0041] In related technologies, when a power component is heated and expands during operation or is cooled and contracted when switching from an operating state to a non-operating state, stress will be generated inside the power component. The inventors discovered that part of the stress generated by the power component will be applied to the insulating substrate. Since the insulating substrate is a rigid electronic component, the stress generated by the power component will gradually damage the insulating substrate of the power component during repeated operation.

[0042] To address the aforementioned technical problems, this application provides a vehicle, which includes a motor and a power module 10.

[0043] The vehicle in this application embodiment can be a hybrid vehicle or a pure electric vehicle. Both hybrid vehicles and pure electric vehicles include a motor for driving the vehicle.

[0044] An electric motor is an electrical device that converts electrical energy into mechanical energy in both directions. It is mainly used to drive vehicles and to recover energy when the vehicle is braking or coasting.

[0045] The core function of the power module 10 is power conversion and control, which can convert DC power into AC power to drive the motor.

[0046] Figure 1 An exemplary cross-sectional view of a power module 10 is shown; Figure 1 The example power module 10 includes a power component 11, a heat sink 12, and a first solder layer 13.

[0047] Heat sink 12 is used to exchange heat with power component 11 to reduce the temperature of power component 11, such as Figure 1 As shown, the heat sink 12 includes a heat dissipation body 121 and a first heat-conducting layer 122, with the first heat-conducting layer 122 disposed on the heat dissipation body 121.

[0048] It is understood that a heat sink 12 can dissipate heat for multiple power components 11. That is, a heat sink 12 has multiple first solder layers 13 connected to it, and each first solder layer 13 is connected to a power component 11. In this way, a heat sink 12 can dissipate heat for multiple power components 11. For example, a heat sink 12 has three first solder layers 13 connected to it, and each first solder layer 13 is connected to a corresponding power component 11.

[0049] In this example, the first heat-conducting layer 122 and the heat dissipation body 121 can be integrally set. In this way, the connection between the first heat-conducting layer 122 and the heat dissipation body 121 is the closest, which facilitates heat exchange between the first heat-conducting layer 122 and the heat dissipation body 121.

[0050] The heat dissipation body 121 is used to exchange heat with the first heat-conducting layer 122. In order to improve the cooling effect of the heat dissipation body 121 on the first heat-conducting layer 122, in some examples, the heat dissipation body 121 is provided with a flow channel for the flow of cooling medium. The heat dissipation body 121 is connected to at least a cooler. After absorbing the heat of the heat dissipation 12, the cooling medium flows to the cooler, and the cooler cools the cooling medium again. The cooled cooling medium flows back to the heat dissipation body 121 and cools the heat dissipation body 121.

[0051] Based on this, the flow channel of the heat dissipation body 121 is bendable to increase the contact area between the cooling medium and the heat dissipation body 121, thereby increasing the cooling effect of the cooling medium on the heat dissipation body 121.

[0052] In this example, the type of heat dissipation body 121 is not limited. The heat dissipation body 121 can be configured as a plate heat exchanger, a coil heat exchanger, a shell and tube heat exchanger, etc.

[0053] In other examples, the surface of the heat dissipation body 121 is provided with heat dissipation fins, which increase the contact area between the heat dissipation body 121 and the air, thereby improving the heat dissipation effect of the heat dissipation body 121.

[0054] The first thermally conductive layer 122 is used to connect the first welding layer 13 and exchange heat with the first welding layer 13. In order to ensure the heat exchange efficiency between the first thermally conductive layer 122 and the first welding layer 13, the first thermally conductive layer 122 should be made of a material with good thermal conductivity, such as silver, copper, aluminum or nickel-based alloy.

[0055] In combination with the above, one heat sink 12 can correspond to multiple power components 11. In some examples, multiple first heat-conducting layers 122 are provided on the heat sink body 121 so that the heat sink 12 can connect to multiple power components 11.

[0056] The power component 11 is used to convert direct current to alternating current. For example, the power component 11 can be an insulated-gate bipolar transistor (IGBT) module. In addition, the power component 11 can also be applied to vehicle battery management systems, charging systems, electronic control systems, or air conditioning systems.

[0057] like Figure 1 As shown, the power component 11 includes an insulating substrate 111, a power chip 112, and a second thermally conductive layer 113, with the power chip 112 and the second thermally conductive layer 113 disposed on opposite sides of the insulating substrate 111.

[0058] The power chip 112 is used to convert low-level, low-current electrical signals into high-level, high-current signals for controlling and managing high-power loads, while realizing efficient power conversion and protection functions. It can be understood that the power chip 112 is the heat source of this application.

[0059] like Figure 1 As shown, in some examples, the number of power chips 112 within each power component 11 can be multiple, with adjacent power chips 112 spaced apart on the insulating substrate 111 to prevent cross-current between the power chips 112. For example, see... Figure 1 Each power component 11 contains two power chips 112, which are spaced apart. Series current refers to an abnormal interconnection of current between different circuits in a power system.

[0060] like Figure 1 As shown, in some examples, in order to improve the heat dissipation rate of the power chip 112, a third thermal conductive layer 114 is connected between the power chip 112 and the insulating substrate 111. The third thermal conductive layer 114 can accelerate the transfer of heat from the power chip 112 to the insulating substrate 111.

[0061] To ensure effective heat dissipation for the power chip 112, the third thermal conductive layer 114 should also be made of a material with good thermal conductivity, such as silver, copper, aluminum, or nickel-based alloys.

[0062] Based on this, in order to connect the power chip 112 and the third heat-conducting layer 114, a second welding layer 115 is connected between the power chip 112 and the third heat-conducting layer 114, and the second welding layer 115 realizes the connection between the power chip 112 and the third heat-conducting layer 114.

[0063] To ensure effective heat dissipation for the power chip 112, such as Figure 1 As shown, in some examples, along the arrangement direction from the first thermal conductive layer 122 to the second thermal conductive layer 113, the orthogonal projection of the second welding layer 115 on the power chip 112 coincides with the power chip 112, so that the contact area between the power chip 112 and the second welding layer 115 reaches the maximum, thereby ensuring the heat transfer efficiency between the power chip 112 and the second welding layer 115.

[0064] To maximize the contact area between the power chip 112 and the second solder layer 115, the orthogonal projection of the power chip 112 onto the third thermal conductive layer 114 is located within the boundary of the third thermal conductive layer 114 along the arrangement direction from the second thermal conductive layer 113 to the first thermal conductive layer 122. In this way, the molten solder can spread across the edge of the power chip 112 in the gap between the power chip 112 and the third thermal conductive layer 114. After the molten solder solidifies, it forms the second solder layer 115 covering the side of the power chip 112 facing the third thermal conductive layer 114.

[0065] The second thermal conductive layer 113 is used for heat exchange with the insulating substrate 111 and for connecting the first solder layer 13. To ensure the heat dissipation effect on the power chip 112, the second thermal conductive layer 113 should be made of a material with good thermal conductivity, such as silver, copper, aluminum or nickel-based alloys.

[0066] The insulating substrate 111 serves as the physical support for the power component 11, and is used to mount and fix the power chip 112 and the second thermal conductive layer 113. When the materials of the second thermal conductive layer 113 and the third thermal conductive layer 114 are both copper, the insulating substrate 111, the second thermal conductive layer 113 and the third thermal conductive layer 114 can constitute a copper-clad substrate (DBC), an active metal brazing substrate (AMB), or a direct plated copper substrate (DPC). That is, the insulating substrate 111 serves as the insulating layer of the copper-clad substrate, the active metal brazing substrate or the direct plated copper substrate, and the second thermal conductive layer 113 and the third thermal conductive layer 114 serve as two copper-clad layers on opposite sides of the copper-clad substrate, the active metal brazing substrate or the direct plated copper substrate.

[0067] Based on this, the insulating substrate 111 can be configured as an alumina insulating layer, an aluminum nitride insulating layer, a silicon nitride insulating layer, or a beryllium oxide insulating layer, etc., to ensure the insulation of the insulating substrate 111. At the same time, the above-mentioned ceramic insulating layers also have good thermal conductivity, which facilitates the cooling of the power chip 112.

[0068] like Figure 1As shown, in some examples, the power component 11 also includes a housing 116, which has an accommodating space and an opening communicating with the accommodating cavity. The power chip 112, the third thermal conductive layer 114, the second solder layer 115, the insulating substrate 111, and the second thermal conductive layer 113 are all located within the accommodating space. The second thermal conductive layer 113 is at least partially exposed to the housing 116 through the opening, that is, the housing 116 encapsulates the power chip 112.

[0069] The first solder layer 13 is used to connect the power component 11 and the heat sink 12, such as Figure 1 As shown, the first welding layer 13 is connected between the first heat-conducting layer 122 and the second heat-conducting layer 113, and the orthographic projection of the first welding layer 13 on the second heat-conducting layer 113 is located within the boundary of the second heat-conducting layer 113.

[0070] During the subsequent soldering of the power component 11 and the heat sink 12, the molten solder spreads through the gap between the second thermally conductive layer 113 and the first thermally conductive layer 122. After cooling, the molten solder forms the first solder layer 13. Since the orthogonal projection of the first solder layer 13 onto the second thermally conductive layer 113 lies within the boundary of the second thermally conductive layer 113, meaning that the second thermally conductive layer 113 is only partially connected to the first solder layer 13, the areas of the second thermally conductive layer 113 where the first solder layer 13 is not laid are more prone to deformation. Thus, a portion of the stress applied to the insulating substrate 111 during the thermal expansion of the power component 11 or the cooling contraction of the power component 11 when switching from an operating state to a non-operating state will be transferred from the insulating substrate 111 to the second thermally conductive layer 113. This reduces the stress applied to the insulating substrate 111 during the thermal expansion or cooling contraction of the power component 11, reduces damage to the insulating substrate 111 during the thermal expansion or cooling contraction of the power component 11, and improves the reliability of the power module.

[0071] To ensure that the orthographic projection of the first solder layer on the second thermally conductive layer 113 after the power component 11 and the heat sink 12 are located within the boundary of the second thermally conductive layer 113, this application provides some achievable structures, as detailed below.

[0072] like Figure 1 As shown, in some examples, along the arrangement direction from the first thermal conductive layer 122 to the second thermal conductive layer 113, the orthogonal projection of the first thermal conductive layer 122 onto the second thermal conductive layer 113 lies within the boundary of the second thermal conductive layer 113.

[0073] At this time, the area of ​​the side of the first heat-conducting layer 122 facing the second heat-conducting layer 113 is smaller than the area of ​​the side of the second heat-conducting layer 113 facing the first heat-conducting layer 122. When the molten solder spreads through the gap between the first heat-conducting layer 122 and the second heat-conducting layer 113, since the area of ​​the side of the first heat-conducting layer 122 facing the first heat-conducting layer 122 is smaller than the area of ​​the side of the second heat-conducting layer 113 facing the first heat-conducting layer 122, the molten solder is difficult to continue spreading on the second heat-conducting layer 113 after it has covered the first heat-conducting layer 122. Thus, the orthographic projection of the first solder layer 13 formed by the solidified molten solder on the second heat-conducting layer 113 is located within the boundary of the second heat-conducting layer 113.

[0074] In some examples, the ratio of the area of ​​the welding surface to the area of ​​the second heat-conducting layer 113 facing the first heat-conducting layer 122 is m, where 0.80 ≤ m ≤ 0.95, for example, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, or 0.94, etc. Within this range, the molten solder, after spreading to the edge of the welding surface after reaching the gap between the welding surface and the second heat-conducting layer 113, is less likely to spread to the edge of the second heat-conducting layer 113, and a first welding layer 13 with a sufficient area is formed between the welding surface and the second heat-conducting layer 113 to ensure the heat dissipation effect of the heat sink 12 on the power component 11.

[0075] In some examples, the shape of the first heat-conducting layer 122 facing the second heat-conducting layer 113 is the same as the shape of the second heat-conducting layer 113 facing the first heat-conducting layer 122, and the axes parallel to the arrangement directions of the first heat-conducting layer 122 and the second guide layer coincide. Thus, the boundary of the first heat-conducting layer 122 and the boundary of the second heat-conducting layer 113 form an annulus of equal width. Therefore, the area of ​​the second heat-conducting layer 113 where the first welding layer 13 is not laid will also form an annulus of equal width. Thus, when the second heat-conducting layer 113 undergoes deformation, the deformation at each location... The distribution is uniform; for example, if the shape of the first heat-conducting layer 122 facing the second heat-conducting layer 113 is rectangular, and the shape of the second heat-conducting layer 113 facing the first heat-conducting layer 122 is also rectangular, then the position of the second heat-conducting layer 113 where the first welding layer 13 is not laid is a square ring of equal width; as another example, if the shape of the first heat-conducting layer 122 facing the second heat-conducting layer 113 is circular, and the shape of the second heat-conducting layer 113 facing the first heat-conducting layer 122 is also circular, then the position of the second heat-conducting layer 113 where the first welding layer 13 is not laid is a circular ring of equal width.

[0076] like Figure 1 As shown, in some other examples, along the arrangement direction from the first thermally conductive layer 122 to the second thermally conductive layer 113, the orthographic projection of the first thermally conductive layer 122 onto the first weld layer 13 is located within the boundary of the first weld layer 13 or coincides with the first weld layer 13.

[0077] The orthographic projection of the first heat-conducting layer 122 on the first welding layer 13 is located within the boundary of the first welding layer 13 or coincides with the first welding layer 13. Since the first welding layer 13 is smaller than the second heat-conducting layer 113, the first heat-conducting layer 122 must be smaller than the first welding layer 13. Thus, the area of ​​the first welding layer 13 laid on the second heat-conducting layer 113 is smaller.

[0078] like Figure 2 or Figure 3 As shown, Figure 2 and Figure 3 All examples exemplarily show a cross-sectional view of a power module 10; in some other examples, the first heat-conducting layer 122 has a welding surface and at least one sidewall adjacent to the welding surface and arranged at an angle, the welding surface is connected to the first welding layer 13, and a first chamfer 1221 is provided at the connection between the welding surface and at least one sidewall.

[0079] The first chamfer 1221 in this example can be configured as follows: Figure 2 The chamfer shown or as Figure 3 The radius of the rounded corner shown in this embodiment can vary, and the included angle between the two right-angled sides of the chamfer is not necessarily equal, that is, it is not necessarily a right angle.

[0080] Chamfering refers to the process of beveling or rounding the edges of a workpiece. In this example, after setting the first chamfer 1221 at the connection between the welding surface and the sidewall, it is equivalent to cutting part of the welding surface when processing the first chamfer 1221, that is, reducing the area of ​​the welding surface, making the area of ​​the welding surface smaller than the area of ​​the second heat-conducting layer 113 facing the first heat-conducting layer 122. When the power component 11 and the heat sink 12 are welded, the molten solder spreads in the gap between the welding surface and the side of the second heat-conducting layer 113 facing the first heat-conducting layer 122. After the molten solder covers the welding surface, it is difficult for it to continue to spread on the side of the second heat-conducting layer 113 facing the first heat-conducting layer 122. Thus, the orthographic projection of the first welding layer 13 formed by the solidified molten solder on the second heat-conducting layer 113 is located within the boundary of the second heat-conducting layer 113.

[0081] For example, the first heat-conducting layer 122 is configured as a cylinder. One end of the cylindrical first heat-conducting layer 122 is connected to the heat dissipation body 121, and the other end is configured as a welding surface. In this case, the first heat-conducting layer 122 has only one annular sidewall. A first chamfer 1221 is provided at the connection between the welding surface and the annular surface. When setting the first chamfer 1221, it is necessary to cut part of the welding surface and part of the annular surface, thus reducing the area of ​​the welding surface.

[0082] For example, the first heat-conducting layer 122 is configured as a prism. One end of the prism-shaped first heat-conducting layer 122 is connected to the heat dissipation body 121, and the other end is configured as a welding surface. In this case, the first heat-conducting layer 122 has at least three sidewalls. The area of ​​the welding surface can be reduced by setting a first chamfer 1221 at the connection between the welding surface and one of the at least three sidewalls.

[0083] It is understandable that the more first chamfers 1221 are provided at the connection between the welded surface and at least three sidewalls, the smaller the value of the arc length or bevel length of the first chamfer 1221 can be.

[0084] When the first heat-conducting layer 122 is configured as a regular prism and the number of prism sidewalls is even, such as a regular square prism, a regular hexagonal prism, or a regular octagonal prism, the multiple first chamfers 1221 are each divided into multiple groups of opposing first chamfers 1221, ensuring that the first weld layer 13 formed after the molten solder solidifies has a regular shape. In this way, the external stress applied to the first heat-conducting layer 122 and the second heat-conducting layer 113 by the regularly shaped first weld layer 13 is more regular.

[0085] like Figure 4 or Figure 5 As shown, Figure 4 and Figure 5 All examples exemplarily show a top view of a heat sink 12; in some further examples, the first thermally conductive layer 122 has a welding surface and a plurality of sidewalls adjacent to the welding surface and at an angle, the welding surface being connected to the first welding layer 13, and a second chamfer 1222 being provided at the connection between at least two adjacent sidewalls of the plurality of sidewalls.

[0086] When the connection between adjacent sidewalls is provided with a second chamfer 1222, part of the welding surface will also be cut, further reducing the area of ​​the welding surface. For example, when the welded part is rectangular, after the first heat-conducting layer 122 is provided with a second chamfer 1222, the four corners of the welding surface will be cut.

[0087] The first chamfer 1221 in this example can be configured as follows: Figure 4 The chamfer shown or as Figure 5 The radius of the rounded corner shown in this embodiment can vary, and the included angle between the two right-angled sides of the chamfer is not necessarily equal, that is, it is not necessarily a right angle.

[0088] Based on this, there are multiple second chamfers 1222, which are evenly distributed about the center point of the welding surface. The evenly distributed second chamfers 1222 make the shape of the first weld layer 13 formed by the molten solder regular, and the external stress exerted by the first weld layer 13 on the second heat-conducting layer 113 and the first heat-conducting layer 122 is also more regular, which can reduce the probability of the first weld layer 13 and the first heat-conducting layer 122 splitting, and also reduce the probability of the second weld layer 115 and the second heat-conducting layer 113 splitting.

[0089] In some examples, a second chamfer 1222 is provided between two adjacent sidewalls, and there are multiple second chamfers 1222. The multiple second chamfers 1222 are divided into multiple groups, and the two second chamfers 1222 in each group are symmetrically arranged about the welding surface, which can also make the shape of the first weld layer 13 formed by the molten solder regular.

[0090] like Figure 6 or Figure 7 As shown, Figure 6 and Figure 7 All examples exemplarily show a top view of a heat sink 12; in some examples, the first thermally conductive layer 122 has a welding surface and a plurality of sidewalls adjacent to the welding surface and forming an angle, the welding surface connects to the first welding layer 13, a first chamfer 1221 is provided between the welding surface and the adjacent sidewalls, and a second chamfer 1222 is provided at the connection between at least two adjacent sidewalls. In this example, after the first chamfer 1221 reduces the area of ​​the welding surface, the second chamfer 1222 also reduces the area of ​​the second welding surface.

[0091] like Figure 8 or Figure 9 As shown, Figure 8 and Figure 9 All images show a cross-sectional view of a power module 10, and in some examples, the first weld layer 13 is also connected to the first chamfer 1221.

[0092] After the first weld layer 13 is connected to the first chamfer 1221, it not only increases the contact area between the first weld layer 13 and the first heat-conducting layer 122, thus increasing the heat exchange area between the first weld layer 13 and the first heat-conducting layer 122, thereby improving the heat dissipation effect of the heat sink 12 on the power component 11, but also does not increase the contact area between the first weld layer 13 and the second heat-conducting layer 113. Figure 8 The diagram shown illustrates the configuration of the first weld layer 13 connected to the first chamfer 1221 with a rounded corner. Figure 9 The diagram shown is a structural schematic of the first weld layer 13 connected to the first chamfer 1221, which is configured as a chamfer.

[0093] like Figure 1 , Figure 2 , Figure 3 , Figure 8 or Figure 9 As shown, in some examples, along the arrangement direction of the first thermal conductive layer 122 to the second thermal conductive layer 113, the orthogonal projection of the first thermal conductive layer 122 onto the power chip 112 covers the power chip 112.

[0094] In this application, the heat transfer path of the power module 10 is as follows: the power chip 112 generates heat as a heat source, and the heat is sequentially transferred from the power chip 112, the second bonding layer 115, the third thermally conductive layer 114, the insulating substrate 111, the first thermally conductive layer 122, the first bonding layer 13, and the second thermally conductive layer 113 to the heat dissipation body 121. The orthogonal projection of the first thermally conductive layer 122 onto the power chip 112 covers the power chip 112, facilitating the transfer of heat generated by the power chip 112 to the first thermally conductive layer 122.

[0095] Along the arrangement direction from the first thermal conductive layer 122 to the second thermal conductive layer 113, after the orthogonal projection of the first thermal conductive layer 122 on the power chip 112 covers the power chip 112, the heat of the power chip 112 can be transferred to the heat dissipation body 121 through a shorter path.

[0096] If the orthogonal projection of the first thermally conductive layer 122 onto the power chip 112 does not cover the power chip 112 along the arrangement direction from the first thermally conductive layer 122 to the second thermally conductive layer 113, then the heat needs to move radially along the second thermally conductive layer 113 on the insulating substrate 111 or the second thermally conductive layer 113 located between the first thermally conductive layer 122 and the power chip 112 before it can be transferred to the first thermally conductive layer 122.

[0097] To further ensure that heat transfer has a shorter path, such as Figure 1 , Figure 2 or Figure 3 As shown, in some examples, along the arrangement direction from the first thermal conductive layer 122 to the second thermal conductive layer 113, the orthogonal projections of the second solder layer 115, the third thermal conductive layer 114, the insulating substrate 111, the second thermal conductive layer 113, and the first solder layer 13 on the power chip 112 all cover the power chip 112. In this case, heat is transferred only along the arrangement direction from the power chip 112 to the heat sink 12 body, and the heat transfer has the shortest path.

[0098] like Figure 1 and Figure 10 As shown, in some examples, the power module 10 also includes a solder resist layer 14, which is disposed on the surface of the second thermally conductive layer 113 facing the first thermally conductive layer 122 and surrounds the periphery of the first solder layer 13.

[0099] The solder resist layer 14 is used for the flow of molten solder on the first thermally conductive layer 122 during post-soldering.

[0100] In some examples, the solder resist layer 14 can be an oxide layer, formed by pre-coating with green solder mask, or formed by pre-coating with adhesive. The green solder mask is a liquid photoresist that can be applied to areas of the circuit board that do not require soldering. The oxide layer can be formed by laser scanning of the second thermally conductive layer 113. Combined with the insulating substrate 111, the second thermally conductive layer 113, and the third thermally conductive layer 114, a copper-clad substrate is formed. After laser scanning, a copper oxide layer is formed on the surface of the second thermally conductive layer 113.

[0101] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0102] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power module, characterized in that, include: A radiator, comprising a heat dissipation body and a first heat-conducting layer, wherein the first heat-conducting layer is disposed on the radiator; A power component, the power component comprising an insulating substrate, a power chip, and a second thermally conductive layer, the power chip and the second thermally conductive layer being disposed on opposite sides of the insulating substrate; and, A first welding layer is connected between the first thermally conductive layer and the second thermally conductive layer; along the arrangement direction from the first thermally conductive layer to the second thermally conductive layer, the orthogonal projection of the first welding layer on the second thermally conductive layer is located within the boundary of the second thermally conductive layer.

2. The power module according to claim 1, characterized in that, Also includes: A solder resist layer is disposed on the surface of the second heat-conducting layer facing the first heat-conducting layer and surrounds the periphery of the first solder layer.

3. The power module according to claim 1, characterized in that, Along the arrangement direction from the first thermally conductive layer to the second thermally conductive layer, the orthographic projection of the first thermally conductive layer onto the second thermally conductive layer lies within the boundary of the second thermally conductive layer; or, Along the arrangement direction from the first thermal conductive layer to the second thermal conductive layer, the orthogonal projection of the first thermal conductive layer onto the first welding layer is located within the boundary of the first welding layer or coincides with the first welding layer.

4. The power module according to any one of claims 1-3, characterized in that, The first heat-conducting layer has a welding surface and at least one sidewall adjacent to the welding surface and arranged at an angle. The welding surface is connected to the first welding layer, and a first chamfer is provided at the connection between the welding surface and at least one sidewall.

5. The power module according to claim 4, characterized in that, The first weld layer is also connected to the first chamfer.

6. The power module according to claim 4, characterized in that, The number of sidewalls is multiple, and at least two adjacent sidewalls among the multiple sidewalls are provided with a second chamfer at the connection.

7. The power module according to any one of claims 1-3, characterized in that, The first heat-conducting layer has a welding surface and a plurality of sidewalls adjacent to the welding surface and forming an angle. The welding surface is connected to the first welding layer, and a second chamfer is provided at the connection between at least two adjacent sidewalls.

8. The power module according to claim 6 or 7, characterized in that, The number of the second chamfers is multiple, and the multiple second chamfers are evenly distributed about the center point of the welding surface.

9. The power module according to any one of claims 1-8, characterized in that, Along the arrangement direction from the first thermal conductive layer to the second thermal conductive layer, the orthogonal projection of the first thermal conductive layer on the power chip covers the power chip.

10. A vehicle, characterized in that, include: Electric motor; and, The power module according to any one of claims 1-9 is electrically connected to the motor.

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