Half-bridge power module, inverter, and vehicle

Abstract

Disclosed in embodiments of the present application are a power module heat dissipation structure, a vehicle, and a packaging device. The power module heat dissipation structure comprises: a power module, a heat dissipation layer, and a solder layer. The power module comprises a chip and a substrate. The chip is located on the substrate. The side of the substrate facing away from the chip is soldered to the heat dissipation layer by means of the solder layer. The power module further comprises a packaging layer. The packaging layer exposes at least part of the side wall of the substrate. The solder layer extends to the side wall of the substrate exposed by the packaging layer. The power module heat dissipation structure provided by the present solution inhibits the formation and growth of cracks in solder joints of the solder layer, improves heat dissipation capability, and also improves the reliability of the solder joints of a power module system.

Description

Half-bridge power module, inverter and vehicle

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202421476663.6, filed on June 25, 2024, and entitled "A power module heat dissipation structure, a vehicle and a packaging device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of electronic devices, in particular to a power module heat dissipation structure, a vehicle and a packaging device. BACKGROUND

[0004] The power module is a core key component in the electric drive system of an electric vehicle, responsible for high-power electric energy conversion in the electric vehicle. The power module has a decisive influence on the performance, efficiency, cost, safety and reliability of the electric drive system and even the whole vehicle. The power module will generate a large amount of heat during operation, which will damage the internal components, so it needs to be cooled. In the early stage, the heat dissipation was mainly achieved by setting a heat-conducting silicone grease between the power module and the heat sink. However, with the improvement of the power module density, this traditional method can no longer meet the heat dissipation requirements.

[0005] At present, the system brazing and system sintering methods are commonly used to weld the direct copper clad ceramic substrate or active metal brazing ceramic substrate of the power module to the heat sink, so as to obtain greater heat dissipation efficiency.

[0006] However, due to the use of system brazing and system sintering, there is a weld at the welding position of the power module and the heat sink. The thermal expansion coefficients of the materials on both sides of the weld are different, and the thermal stress at the boundary and the corner area of the weld is large, which makes it easy to generate cracks from the edge of the weld and expand to the inside of the weld. Therefore, the effective heat transfer area of the power module and the heat sink is reduced, and the heat dissipation capacity is decreased.

[0007] Content of the utility model

[0008] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a power module heat dissipation structure, a vehicle and a packaging device.

[0009] In a first aspect, the present application provides a power module heat dissipation structure, the method comprising:

[0010] The power module, the heat dissipation layer and the welding layer;

[0011] The power module comprises a chip and a backing plate; the chip is located on the backing plate;

[0012] The side of the backing plate away from the chip is welded to the heat dissipation layer through the welding layer;

[0013] The power module further comprises a packaging layer; the packaging layer exposes at least part of the sidewall of the backing plate, and the welding layer extends to the sidewall of the backing plate exposed by the packaging layer.

[0014] Optionally, the power module comprises a first backing plate and a second backing plate; the chip is located between the first backing plate and the second backing plate; the heat dissipation layer comprises a first heat dissipation layer and a second heat dissipation layer; the welding layer comprises a first welding layer and a second welding layer;

[0015] The side of the first backing plate away from the chip is welded to the first heat dissipation layer through the first welding layer; the side of the second backing plate away from the chip is welded to the second heat dissipation layer through the second welding layer.

[0016] The packaging layer exposes at least part of the sidewall of the first backing plate and at least part of the sidewall of the second backing plate, the first welding layer covers the sidewall of the first backing plate exposed by the packaging layer; and the second welding layer covers the sidewall of the second backing plate exposed by the packaging layer.

[0017] Optionally, the backing plate of the power module comprises a first metal layer, an insulating layer and a second metal layer arranged in a stack; the second metal layer is welded to the heat dissipation layer through the welding layer; and the chip is located on the first metal layer.

[0018] The packaging layer exposes at least part of the sidewall of the second metal layer, and the welding layer extends to the sidewall of the second metal layer exposed by the packaging layer.

[0019] Optionally, the edge of the first metal layer and the edge of the second metal layer are located within the edge of the insulating layer in projection.

[0020] Optionally, the packaging layer covers the edge of the insulating layer.

[0021] Optionally, a gasket is arranged between the chip and the first backing plate.

[0022] Optionally, the backing plate comprises a direct copper clad ceramic substrate or an active metal brazing ceramic substrate.

[0023] In a second aspect, the application provides a vehicle comprising any one of the power module heat dissipation structures according to the first aspect.

[0024] In a third aspect, the application provides a packaging device for a power module heat dissipation structure, comprising:

[0025] A packaging layer removing device for removing a packaging layer of at least part of a sidewall of a backing plate of a power module,

[0026] A welding device for welding a side of the backing plate away from a chip of the power module to a heat dissipation layer through a welding layer, so that the welding layer extends to the sidewall of the backing plate exposed by the packaging layer.

[0027] Optionally, the packaging layer removing device comprises a laser.

[0028] In a fourth aspect, the application provides a packaging method of a power module heat dissipation structure, the vehicle comprising any one of the power module heat dissipation structures according to the first aspect, wherein the method comprises:

[0029] Removing a packaging layer of at least part of a sidewall of a backing plate of a power module,

[0030] Welding a side of the backing plate away from a chip of the power module to a heat dissipation layer through a welding layer, so that the welding layer extends to the sidewall of the backing plate exposed by the packaging layer.

[0031] Optionally, the power module comprises a first backing plate and a second backing plate; the chip is located between the first backing plate and the second backing plate; the heat dissipation layer comprises a first heat dissipation layer and a second heat dissipation layer; the welding layer comprises a first welding layer and a second welding layer;

[0032] The removing a packaging layer of at least part of a sidewall of a backing plate of a power module comprises removing a packaging layer of at least part of a sidewall of the first backing plate and removing a packaging layer of at least part of a sidewall of the second backing plate;

[0033] The welding a side of the backing plate away from a chip of the power module to a heat dissipation layer through a welding layer, so that the welding layer extends to the sidewall of the backing plate exposed by the packaging layer comprises welding a side of the first backing plate away from the chip to the first heat dissipation layer through the first welding layer, so that the first welding layer extends to the sidewall of the first backing plate exposed by the packaging layer; and welding a side of the second backing plate away from the chip to the second heat dissipation layer through the second welding layer, so that the second welding layer extends to the sidewall of the second backing plate exposed by the packaging layer.

[0034] Optionally, the removing a packaging layer of at least part of a sidewall of a backing plate of a power module by using a laser etching process comprises:

[0035] Controlling a laser emission direction to be parallel to a normal line of a sidewall to be etched of the backing plate, and removing a packaging layer of at least part of a sidewall of a backing plate of a power module by using a laser etching process.

[0036] Compared with the prior art, the technical scheme provided by the embodiments of the application has the following advantages:

[0037] The power module heat dissipation structure provided by the scheme can make the welding layer extend to the side wall of the lining exposed by the packaging layer by removing part of the packaging layer and making the packaging layer expose at least part of the side wall of the lining, so that the welding layer extends to the side wall of the lining exposed by the packaging layer. Compared with the welding layer only located at the welding seam between the power module and the heat sink in the prior art, the present application can avoid the cracks of the welding seam at the four corner regions of the lining in the prior art, and inhibit the occurrence and growth rate of the welding seam cracks. Therefore, the effective heat transfer area between the power module and the heat sink can be maintained, the heat dissipation capacity is improved, and the reliability of the power module is improved.

[0038] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0039] The drawings incorporated into the specification and forming part of the specification show embodiments consistent with the present application and, together with the specification, serve to explain the principles of the present application.

[0040] In order to more clearly illustrate the technical scheme of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor.

[0041] Fig. 1 is a schematic diagram of a power module heat dissipation structure provided by the prior art;

[0042] Fig. 2 is a schematic diagram of another power module heat dissipation structure provided by the embodiments of the present application;

[0043] Fig. 3 is a schematic diagram of another power module heat dissipation structure provided by the embodiments of the present application;

[0044] Fig. 4 is a schematic diagram of another power module heat dissipation structure provided by the embodiments of the present application;

[0045] Fig. 5 is a schematic diagram of another power module heat dissipation structure provided by the embodiments of the present application;

[0046] Fig. 6 is a packaging method flow chart of a power module heat dissipation structure provided by the embodiments of the present application;

[0047] Fig. 7 is a schematic diagram of a laser etching process of a power module packaging method provided by the embodiments of the present application. DETAILED DESCRIPTION

[0048] In order to enable the above-mentioned objects, features and advantages of the present application to be clearer, the following will further describe the solutions of the present application. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0049] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in other ways different from those described herein; obviously, the embodiments described in the specification are only part of the embodiments of the present application, not all the embodiments.

[0050] Before introducing the power module heat dissipation structure proposed in the present application, the problems existing in the current power module and the solutions of the prior art are introduced, so that the subsequent understanding of the present application is easier.

[0051] The power module is a core and key component in the electric drive system of an electric vehicle, responsible for high-power electric energy conversion in the electric vehicle. The power module has a decisive influence on the performance, efficiency, cost, safety and reliability of the electric drive system and even the whole vehicle. The power module will generate a large amount of heat during operation, which will damage the internal components, so it needs to be cooled. In the early stage, the heat dissipation was mainly achieved by setting a heat-conducting silicone grease between the power module and the heat sink. However, with the improvement of the power module density, this traditional method can no longer meet the heat dissipation requirements.

[0052] At present, the system brazing and system sintering methods are commonly used to weld the direct copper clad ceramic substrate or active metal brazing ceramic substrate of the power module to the heat sink, so that greater heat dissipation efficiency can be obtained.

[0053] Among them, the ceramic substrate composition of the direct copper clad ceramic substrate mainly includes aluminum oxide, aluminum nitride, or doped zirconium oxide, which can be used as a packaging substrate of the power module. The active metal brazing ceramic substrate is an upgraded product of the direct copper clad ceramic substrate, and its heat conductivity and reliability are more advantageous. At present, the packaging substrate of the power module mainly adopts the active metal brazing ceramic substrate.

[0054] Exemplarily, FIG. 1 is a schematic diagram of a power module heat dissipation structure provided by the prior art. As shown in FIG. 1, the power module heat dissipation structure provided by the prior art includes a packaging layer 101, a chip 102, a backing plate 103, a welding layer 104 and a heat dissipation layer 105.

[0055] In order to enable the power module to dissipate heat more effectively, the backing plate 103 of the power module is connected together with the heat dissipation layer 105 through the welding layer 104, and the heat dissipation plate plays a heat dissipation function by setting a water cooling system inside.

[0056] However, the power module heat dissipation structure using the prior art has problems in the reliability of the solder joint formed by the solder layer 104 because of the difference in the coefficient of thermal expansion between the solder joint formed by the solder layer 104 and the system on both sides of the solder joint.

[0057] The power module is composed of multiple materials, and the coefficient of thermal expansion at the interface where the power module is connected to the solder layer 104 is about 6-8; the solder joint formed by the solder layer 104 is usually a tin-based metal alloy, and the coefficient of thermal expansion of the solder layer 104 is about 20; the material of the heat dissipation layer 105 is usually copper or aluminum, and the coefficient of thermal expansion of the heat dissipation layer 105 is about 18-23. Due to the difference in the coefficient of thermal expansion of the object, the thermal stress received when the temperature changes will also be different, so the interface where the power module is connected to the solder layer 104 is the area with the highest thermal stress. When the power module heat dissipation structure is subjected to temperature cycle test, the solder joint formed by the solder layer 104 will bear the cyclically changing thermal stress due to the influence of temperature, and the interface where the power module is connected to the solder layer 104 bears the maximum thermal stress. Because the solder joint formed by the solder layer 104 is usually a tin-based metal alloy, the material strength at the solder layer 104 is the lowest, and as the temperature rises, the strength of the solder layer 104 will decrease by half or even more, so it is easy to cause cracks at the edge of the solder layer 104 and expand to the inside of the solder layer 104, resulting in a decrease in the effective heat transfer area of the power module and the heat dissipation layer 105 and a decrease in the heat dissipation capacity.

[0058] In order to solve the problem in the prior art that the solder layer of the power module is prone to cracks, resulting in ineffective heat dissipation of the power module heat dissipation structure, the present application provides a power module heat dissipation structure, a packaging method and a vehicle to effectively solve the problems in the prior art. Hereinafter, the power module heat dissipation structure provided by the present application will be introduced.

[0059] Exemplarily, FIG. 2 is a schematic diagram of a power module heat dissipation structure provided by an embodiment of the present application. As shown in FIG. 2, the power module heat dissipation structure provided by the embodiment of the present application includes a power module 20, a heat dissipation layer 201 and a solder layer 202.

[0060] Among them, the positional relationship between each part in the power module 20 heat dissipation structure is:

[0061] The power module 20 includes a chip 203 and a backing plate 204, and the chip 203 is located on the backing plate 204; the side of the backing plate 204 away from the chip 203 is soldered to the heat dissipation layer 201 through the solder layer 202.

[0062] Optionally, the backing plate 204 comprises a direct copper clad ceramic substrate or an active metal brazing ceramic substrate. Specifically, the active metal brazing ceramic substrate is printed on the ceramic substrate by using a silk screen printing technique with a small amount of active elements added in the brazing electronic paste, and then sintered in a vacuum brazing furnace after covering with oxygen-free copper. Then, the circuit is made by etching the pattern and finally the surface pattern is chemically plated. The direct copper clad ceramic substrate has the characteristics of excellent thermal cycling, shape stability, good rigidity, high thermal conductivity, high reliability, and the copper clad surface can be etched into various patterns. It should be noted that the selection of the backing plate 204 is not limited to the above two substrates, and other substrates with good thermal conductivity can also be used, which are not limited here.

[0063] Optionally, the heat dissipation layer 201 can use a water cooling system based heat sink. Specifically, the water in the heat sink is cooled by a cooling device to reduce the temperature, and the water flows through the corresponding channel to take away the heat, so that the power module is kept at a lower temperature to ensure its normal work. It should be noted that the selection of the heat dissipation layer 201 is not limited to the above water cooling system based heat sink, and other heat sinks with good heat dissipation performance can also be used, which are not limited here.

[0064] Optionally, the welding layer 202 can be formed by system brazing. Specifically, system brazing uses a filler material with a much lower melting point than the base material. By heating the welding part and the filler material to a temperature slightly higher than the melting point of the filler material but lower than the melting temperature of the base material, the liquid filler material can wet the surface of the base material, and finally solidify to form a tightly connected joint. It should be noted that the formation of the welding layer 202 is not limited to the above system brazing, and other welding methods can also be used, which are not limited here.

[0065] The power module further comprises a packaging layer 205. In order to protect the chip from environmental factors such as moisture and dust, the packaging layer 205 is usually used for packaging. After the power module is packaged, the side of the backing plate 204 away from the chip 203 is welded to the heat dissipation layer 201 through the welding layer 202. The welding layer 202, for example, by brazing process, makes the side of the backing plate 204 away from the chip 203 welded and connected with the heat dissipation layer 201.

[0066] To eliminate the stress concentration phenomenon at the edge of the welding layer, the packaging layer 205 is arranged to expose at least part of the sidewall of the backing plate 204 before the welding layer 202 is welded to connect the side of the backing plate 204 away from the chip 203 to the heat dissipation layer 201. Referring to FIG. 2, the packaging layer 205 is removed to expose at least part of the sidewall of the backing plate 204, for example, at the position shown by the dashed box in FIG. 2. Since at least part of the sidewall of the backing plate 204 is exposed, during the process of welding the side of the backing plate 204 away from the chip 203 to the heat dissipation layer 201 by brazing, the welding layer 202 can extend to the sidewall of the backing plate 204 exposed by the packaging layer 205, that is, the welding layer 202 can longitudinally climb on the sidewall of the exposed backing plate 204, eliminating the stress concentration problem of the welding layer at the four edges of the bottom surface of the backing plate in the prior art, thereby reducing the risk of cracking of the welding layer and inhibiting the occurrence and growth rate of the welding layer cracks. Therefore, the effective heat transfer area between the power module and the heat dissipation layer can be maintained, the heat dissipation capacity is improved, and the reliability of the power module system weld is also improved.

[0067] In some embodiments, the composition of the welding layer mainly includes a tin-based metal alloy, and the bottom backing plate of the power module and the heat dissipation layer are directly combined together by using the principle of metallurgical bonding of metals through system brazing and system sintering. The heat dissipation layer can use a heat sink with a water-cooled heat dissipation system. Therefore, by using the power module heat dissipation structure provided in the embodiments of the present application, cracks are less likely to occur from the outside to the inside at the welding position between the power module and the heat sink, and the occurrence and growth rate of the welding cracks are inhibited. Therefore, the effective heat transfer area between the power module and the heat sink can be maintained, the heat dissipation capacity is improved, and the reliability of the power module system weld is also improved.

[0068] Exemplarily, FIG. 3 is a schematic diagram of another power module heat dissipation structure provided by the embodiments of the present application. As shown in FIG. 3, the power module heat dissipation structure provided by the embodiments of the present application includes a first backing plate 301 and a second backing plate 302; a chip 303 is located between the first backing plate 301 and the second backing plate 302; a heat dissipation layer includes a first heat dissipation layer 304 and a second heat dissipation layer 305; and a welding layer includes a first welding layer 306 and a second welding layer 307.

[0069] The side of the first backing plate 301 away from the chip 303 is welded to the first heat dissipation layer 304 by the first welding layer 306; and the side of the second backing plate 302 away from the chip 303 is welded to the second heat dissipation layer 305 by the second welding layer 307.

[0070] The encapsulation layer 308 exposes at least part of the sidewall of the first backing plate 301 and at least part of the sidewall of the second backing plate 302, the first solder layer 306 covers the sidewall of the first backing plate 301 exposed by the encapsulation layer 308, and the second solder layer 307 covers the sidewall of the second backing plate 302 exposed by the encapsulation layer 308.

[0071] After the first backing plate 301 and the second backing plate 302 are provided, the chip 303 is attached between the first backing plate 301 and the second backing plate 302 and connected to the pins. In order to achieve greater heat dissipation efficiency, the power module is double-sided soldered with the two heat sinks in the embodiment of the present application, and in order to eliminate the stress concentration phenomenon at the edges of the first heat dissipation layer 304 and the second heat dissipation layer 305, the encapsulation layer 308 is arranged to expose at least part of the sidewall of the first backing plate 301 before the first backing plate 301 away from the chip 303 is soldered and connected with the first heat dissipation layer 304 through the first solder layer 306, so that the first solder layer 306 extends to the sidewall of the first backing plate 301 exposed by the encapsulation layer 308. Referring to FIG. 3, the encapsulation layer 308 is removed in the embodiment of the present application to expose at least part of the sidewall of the first backing plate 301, for example, the position shown in the dashed box 309 in FIG. 3. Moreover, the encapsulation layer 308 is arranged to expose at least part of the sidewall of the second backing plate 302 before the second backing plate 302 away from the chip 303 is soldered and connected with the second heat dissipation layer 305 through the second solder layer 307, so that the second solder layer 307 extends to the sidewall of the second backing plate 302 exposed by the encapsulation layer 308. Referring to FIG. 3, the encapsulation layer 308 is removed in the embodiment of the present application to expose at least part of the sidewall of the second backing plate 302, for example, the position shown in the dashed box 310 in FIG. 3.

[0072] Since at least part of the sidewall of the first backing plate 301 and at least part of the sidewall of the second backing plate 302 are exposed, the first solder layer 306 can extend to the sidewall of the first backing plate 301 exposed by the encapsulation layer 308 during the process of soldering and connecting the first backing plate 301 away from the chip 303 with the first heat dissipation layer 304 through the brazing process, that is, the first solder layer 306 can longitudinally climb on the exposed sidewall of the first backing plate 301. Similarly, the second solder layer 307 can extend to the sidewall of the second backing plate 302 exposed by the encapsulation layer 308 during the process of soldering and connecting the second backing plate 302 away from the chip 303 with the second heat dissipation layer 305 through the brazing process, that is, the second solder layer 307 can longitudinally climb on the exposed sidewall of the second backing plate 302, eliminating the stress concentration problem of the solder layer at the four edges of the bottom surface of the backing plate in the prior art, thereby reducing the risk of cracking of the solder layer and inhibiting the occurrence and growth rate of the solder layer cracks. Moreover, the double-sided soldering of the power module with the two heat sinks can achieve greater heat dissipation efficiency. Therefore, the effective heat transfer area between the power module and the heat dissipation layer can be maintained, the heat dissipation capacity is improved, and the reliability of the power module system weld is also improved.

[0073] The power module heat dissipation structure provided by the embodiment of the present application realizes greater heat dissipation efficiency by arranging the heat dissipation layers on the upper and lower surfaces of the power module and connecting the heat dissipation layers to the power module through the welding layers. Since the two welding layers can climb on the side walls of the exposed backing plates, the effective heat transfer area between the power module and the heat dissipation layers can be maintained, and the reliability of the power module system weld is improved.

[0074] In some embodiments, a gasket can be arranged between the chip and the first backing plate.

[0075] FIG. 4 is a schematic diagram of another power module heat dissipation structure provided by the embodiment of the present application. As shown in FIG. 4, the power module of the power module heat dissipation structure provided by the embodiment of the present application includes a first backing plate 401 and a second backing plate 402; a chip 403 is located between the first backing plate 401 and the second backing plate 402, and a gasket 404 is arranged between the chip 403 and the first backing plate 401, and the chip 403 is connected to the gasket 404; a heat dissipation layer includes a first heat dissipation layer 405 and a second heat dissipation layer 406; a welding layer includes a first welding layer 407 and a second welding layer 408.

[0076] The side of the first backing plate 401 away from the chip 403 is welded to the first heat dissipation layer 405 through the first welding layer 407; and the side of the second backing plate 402 away from the chip 403 is welded to the second heat dissipation layer 406 through the second welding layer 408.

[0077] The encapsulation layer 409 exposes at least part of the side walls of the first backing plate 401 and at least part of the side walls of the second backing plate 402, the first welding layer 407 covers the side walls of the first backing plate 401 exposed by the encapsulation layer 409; and the second welding layer 408 covers the side walls of the second backing plate 402 exposed by the encapsulation layer 409.

[0078] In order to realize greater heat dissipation efficiency, the power module is double-sided welded to two heat sinks, and in order to eliminate the stress concentration phenomenon at the edges of the first heat dissipation layer 405 and the second heat dissipation layer 406, the embodiment of the present application exposes at least part of the side walls of the first backing plate 401 by arranging the encapsulation layer 409 before the side of the first backing plate 401 away from the chip 403 is welded and connected to the first heat dissipation layer 405 through the first welding layer 407, so that the first welding layer 407 extends to the side walls of the first backing plate 401 exposed by the encapsulation layer 409. Referring to FIG. 4, the embodiment of the present application removes part of the encapsulation layer 409 to expose at least part of the side walls of the first backing plate 401, for example, the position shown by the dashed box 410 in FIG. 4.

[0079] And before the second backer plate 402 is welded to the second heat sink 406 through the second welding layer 408 on the side away from the chip 403, a packaging layer 409 is arranged to expose at least part of the side wall of the second backer plate 402, so that the second welding layer 408 extends to the side wall of the second backer plate 402 exposed by the packaging layer 409. Referring to FIG. 4, the packaging layer 409 is removed in the embodiment of the application to expose at least part of the side wall of the second backer plate 402, for example, at the position shown by the dashed box 411 in FIG. 4.

[0080] Since at least part of the side wall of the first backer plate 401 and the second backer plate 402 is exposed, during the welding connection of the first backer plate 401 and the second backer plate 402 to the first heat sink 405 and the second heat sink 406 on the side away from the chip 403 through the brazing process, the first welding layer 407 and the second welding layer 408 can respectively extend to the side wall of the first backer plate 401 and the second backer plate 402 exposed by the packaging layer 409, that is, the first welding layer 407 and the second welding layer 408 can longitudinally climb on the exposed side wall of the first backer plate 401 and the second backer plate 402, eliminating the stress concentration problem of the welding layer at the four edges of the bottom surface of the backer plate in the prior art, thereby reducing the risk of cracking of the welding layer and inhibiting the occurrence and growth rate of the welding layer cracks. Moreover, the double-sided welding of the power module and the two heat sinks can achieve greater heat dissipation efficiency. Therefore, the effective heat transfer area between the power module and the heat sink can be maintained, the heat dissipation capacity is improved, and the reliability of the power module system weld is also improved.

[0081] Since the first backer plate 401 and the second backer plate 402 have a high potential difference, and the chip 403 has a small thickness, the first backer plate 401 and the second backer plate 402 are prone to short circuit. Therefore, the power module heat dissipation structure provided in the embodiment of the application is arranged with a gasket 404 between the chip 403 and the first backer plate 401 to increase the distance between the first backer plate 401 and the second backer plate 402, so as to ensure the electrical insulation between the first backer plate and the second backer plate, so that the chip 403 can work normally.

[0082] In some embodiments, the backer plate of the power module includes a first metal layer, an insulating layer and a second metal layer arranged in layers; the second metal layer is welded to the heat sink through the welding layer; the chip is located on the first metal layer; the packaging layer exposes at least part of the side wall of the second metal layer, and the welding layer extends to the side wall of the second metal layer exposed by the packaging layer.

[0083] For example, referring to FIG. 2, the backing plate 204 includes a first metal layer 2041, an insulating layer 2042, and a second metal layer 2043 stacked together. The chip 203 is disposed on the first metal layer 2041. After encapsulation by the encapsulation layer 205, at least part of the side wall of the second metal layer 2043 is exposed by removing the encapsulation layer 205 therefrom. The second metal layer 2043 is then soldered to the heat dissipation layer 201 via the solder layer 202. Since the solder can infiltrate the side wall of the second metal layer 2043, the solder layer 202 can extend to the side wall of the second metal layer 2043 exposed by the encapsulation layer 205 during formation of the solder layer 202.

[0084] It should be noted that the encapsulation layer 205 is configured to expose part of the side wall of the second metal layer 2043 in the example of FIG. 2. In other embodiments, the size of the side wall of the second metal layer 2043 exposed by the encapsulation layer 205 can be adjusted according to actual conditions. For example, the encapsulation layer 205 can be configured to expose the entire side wall of the second metal layer 2043.

[0085] For power modules requiring heat dissipation on both sides, the first backing plate and the second backing plate can also include a first metal layer, an insulating layer, and a second metal layer stacked together. For example, referring to FIG. 5, the first backing plate 501 and the second backing plate 502 of the power module each include a first metal layer, an insulating layer, and a second metal layer stacked together. The first metal layer, the insulating layer, and the second metal layer in the first backing plate 501 are labeled as a first film layer 5011, a second film layer 5012, and a third film layer 5013, respectively. The first metal layer, the insulating layer, and the second metal layer in the second backing plate 502 are labeled as a fourth film layer 5023, a fifth film layer 5022, and a sixth film layer 5021, respectively. The third film layer 5013 is soldered to the first heat dissipation layer 505 via the first solder layer 504. The sixth film layer 5021 is soldered to the second heat dissipation layer 512 via the second solder layer 511. The gasket 506 is located between the chip 513 and the first backing plate 501, and the chip 513 is disposed on the first metal layer 5023. The encapsulation layer 507 exposes at least part of the side wall of the third film layer 5013 of the first backing plate 501 and the sixth film layer 5021 of the second backing plate 502. The first solder layer 504 extends to the side wall of the third film layer 5013 exposed by the encapsulation layer 507. The second solder layer 511 extends to the side wall of the sixth film layer 5021 exposed by the encapsulation layer 507.

[0086] In some embodiments, the edge of the first metal layer and the edge of the second metal layer are located within the edge of the insulating layer in projection.

[0087] Since there is a relatively large voltage difference between the first metal layer and the second metal layer when the power module is working, to avoid current flowing from one side of the metal layer to the other side of the metal layer through the insulating layer, thereby causing the creepage effect of the backing plate of the power module, the embodiment sets the projection of the edge of the first metal layer and the edge of the second metal layer on the insulating layer within the edge of the insulating layer, that is, the edge of the insulating layer exceeds the edge of the first metal layer and the edge of the second metal layer, so that the creepage path is increased, thereby effectively inhibiting the creepage effect.

[0088] In some embodiments, the encapsulation layer covers the edge of the insulating layer.

[0089] Since there is a relatively large voltage difference between the first metal layer and the second metal layer when the power module is working, when the encapsulation layer is removed, only the encapsulation layer on the sidewall of the second metal layer is removed, so that the encapsulation layer covers the edge of the insulating layer, and then the solder can climb to the insulating layer, thereby causing the creepage effect of the backing plate of the power module.

[0090] The embodiment of the present application also provides a vehicle, and the power module heat dissipation structure in the vehicle can adopt any one of the power module heat dissipation structures described above, so that the vehicle has the technical features of the power module heat dissipation structure provided by the embodiment of the present application, and can achieve the beneficial effects of the power module heat dissipation structure provided by the embodiment of the present application. The same parts can be referred to the description of the power module heat dissipation structure provided by the embodiment of the present application, and will not be described here.

[0091] The embodiment of the present application also provides a packaging device of a power module heat dissipation structure, which comprises:

[0092] an encapsulation layer removing device configured to remove the encapsulation layer on at least part of the sidewall of the backing plate of the power module,

[0093] a welding device configured to weld the side of the backing plate away from the chip of the power module to the heat dissipation layer through a soldering layer, so that the soldering layer extends to the sidewall of the backing plate exposed by the encapsulation layer.

[0094] The packaging device of the power module heat dissipation structure provided by the embodiment of the present application can package the power module heat dissipation structure described in any of the above embodiments.

[0095] In some embodiments, the encapsulation layer removing device comprises a laser.

[0096] When the encapsulation layer of the at least part of the sidewall of the backing plate of the power module is removed, the insulation layer is easy to be cracked if a mechanical method is used, and the metal layer is easy to be corroded if an etching process is used, thereby reducing the insulation of the module. The encapsulation layer of the at least part of the sidewall of the backing plate of the power module is removed by using a laser in the embodiment of the application, so that the integrity of the insulation layer and the metal layer is ensured, and the good insulation is ensured.

[0097] The embodiment of the application further provides an encapsulation method of a power module heat dissipation structure, which is suitable for the power module heat dissipation structure in any of the above embodiments. Exemplarily, FIG. 6 is a flow chart of an encapsulation method of a power module heat dissipation structure provided by the embodiment of the application. As shown in FIG. 6, the encapsulation method of the power module heat dissipation structure provided by the embodiment of the application comprises S601-S602:

[0098] S601: removing the encapsulation layer of the at least part of the sidewall of the backing plate of the power module.

[0099] S602: welding the side of the backing plate, which is away from the chip of the power module, to the heat dissipation layer through the solder layer, so that the solder layer extends to the sidewall of the backing plate exposed by the encapsulation layer.

[0100] The encapsulation method of the power module heat dissipation structure provided by the scheme can expose part of the sidewall of the backing plate of the power module, and then extend the solder layer to the sidewall of the backing plate exposed by the encapsulation layer. This structure can eliminate the problem of excessive thermal stress around the solder layer, thereby reducing the risk of cracking of the solder layer and inhibiting the occurrence and growth rate of cracks in the solder layer. Therefore, the effective heat transfer area between the power module and the heat dissipation layer can be maintained, and the heat dissipation capacity can be improved.

[0101] In some embodiments, the backing plate of the power module heat dissipation structure comprises a first metal layer, an insulation layer and a second metal layer which are arranged in layers; the second metal layer is welded to the heat dissipation layer through the solder layer; and the chip is located on the first metal layer.

[0102] Correspondingly, removing the encapsulation layer of the at least part of the sidewall of the backing plate of the power module comprises removing the encapsulation layer of the at least part of the sidewall of the second metal layer.

[0103] Welding the side of the backing plate, which is away from the chip of the power module, to the heat dissipation layer through the solder layer, so that the solder layer extends to the sidewall of the backing plate exposed by the encapsulation layer, comprises welding the second metal layer to the heat dissipation layer through the solder layer, so that the solder layer extends to the sidewall of the second metal layer.

[0104] In some embodiments, the power module comprises a first backing plate and a second backing plate; the chip is located between the first backing plate and the second backing plate; the heat dissipation layer comprises a first heat dissipation layer and a second heat dissipation layer; and the solder layer comprises a first solder layer and a second solder layer.

[0105] Accordingly, removing the encapsulation layer from at least a portion of the sidewalls of the power module's substrate includes: removing the encapsulation layer from at least a portion of the sidewalls of the first substrate and the encapsulation layer from at least a portion of the sidewalls of the second substrate.

[0106] Soldering the side of the substrate away from the chip of the power module to the heat dissipation layer through a solder layer, such that the solder layer extends to the sidewall of the substrate exposed by the encapsulation layer, includes: soldering the side of the first substrate away from the chip to the first heat dissipation layer through a first solder layer, such that the first solder layer extends to the sidewall of the first substrate exposed by the encapsulation layer; and soldering the side of the second substrate away from the chip to the second heat dissipation layer through a second solder layer, such that the second solder layer extends to the sidewall of the second substrate exposed by the encapsulation layer.

[0107] In some embodiments, removing the encapsulation layer of at least a portion of the sidewalls of the power module substrate includes: removing the encapsulation layer of at least a portion of the sidewalls of the power module substrate using a laser etching process.

[0108] When removing the encapsulation layer at the corresponding location of the power module, mechanical methods used in the prior art can easily cause the insulation layer to crack, while etching processes used in the prior art can easily cause the metal layer to corrode, thereby reducing the insulation performance of the module. This application embodiment uses laser etching to remove the encapsulation layer from at least a portion of the sidewalls of the power module's substrate, which can ensure the integrity of the insulation layer and prevent corrosion of the metal layer, thus guaranteeing good insulation performance.

[0109] In some embodiments, removing the encapsulation layer of at least a portion of the sidewall of the substrate of the power module using a laser etching process includes: controlling the laser emission direction to be parallel to the normal of the sidewall to be etched of the substrate, and removing the encapsulation layer of at least a portion of the sidewall of the substrate of the power module using a laser etching process.

[0110] For example, Figure 7 is a schematic diagram of the laser etching process of a power module packaging method provided in an embodiment of this application. As shown in Figure 7, the schematic diagram of the laser etching process of a power module heat dissipation structure packaging method provided in an embodiment of this application includes a laser 701, a substrate 702, a chip 703, and a packaging layer 704.

[0111] The chip 703 is located on the substrate 702, and is encapsulated by the encapsulation layer 704 to protect the chip from environmental damage.

[0112] Specifically, due to process reasons, the sidewall of the backing plate 702 is arc-shaped. When using a laser etching process to remove the encapsulation layer of at least part of the sidewall of the backing plate of the power module, the power module is fixed at an angle, so that the laser emission direction of the laser is parallel to the normal line of the to-be-etched sidewall of the backing plate. The dashed line 705 in FIG. 7 represents the normal line of the to-be-etched sidewall. For example, by controlling the laser to swing through a galvanometer, the laser emission direction can always be kept in a position parallel to the normal line of the to-be-etched sidewall of the backing plate, and the encapsulation layer irradiated by the laser is slowly removed by the laser until at least part of the sidewall of the backing plate is exposed. By using the above laser etching process method, the laser emission direction of the laser is always controlled to be parallel to the normal line of the to-be-etched sidewall of the backing plate, so that the laser can be focused on the sidewall surface to remove the encapsulation glue on the sidewall, thereby avoiding the problem that the encapsulation layer of the sidewall of the backing plate cannot be completely removed due to the failure of the laser to focus.

[0113] For a rectangular backing plate, the backing plate includes four edges. The power module can be rotated by 90 degrees, 180 degrees, and 270 degrees in sequence, and the above laser etching process is used to remove the encapsulation layer of at least part of the sidewall of the four edges of the backing plate of the power module.

[0114] In some embodiments, for example, referring to FIG. 7, the backing plate 702 includes a first metal layer 7021, an insulating layer 7022, and a second metal layer 7023 arranged in layers. The chip 703 is arranged on the first metal layer 7021 and encapsulated by the encapsulation layer 704. Due to process reasons, the sidewall of the first metal layer 7021 and the second metal layer 7023 is arc-shaped. When using a laser etching process to remove the encapsulation layer of at least part of the sidewall of the second metal layer 7023, the power module can be fixed at an angle, so that the laser emission direction of the laser is parallel to the normal line of the to-be-etched sidewall of the second metal layer of the backing plate, and the laser is controlled to swing through a galvanometer, so that the laser is always kept in a position parallel to the normal line of the to-be-etched sidewall of the second metal layer of the backing plate. The encapsulation layer irradiated by the laser emission direction of the laser is slowly removed until the sidewall of the second metal layer of the backing plate is exposed.

[0115] It has to be understood that any reference signs in the claims should not be construed as limiting the scope of the claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unitary claim, several devices, apparatuses or means can be listed, comprising means for carrying out a certain task. The use of the term "a" or "one" preceding these means does not exclude the use of a plurality of such means, but it is possible that the task is carried out by a single one of the means. The use of the term "first", "second" and the like does not imply any order but is used for the purpose of naming. The word "comprise" or "comprising" or "including" or "containing" shall not be construed as meaning "consist only of" or "consisting only of".

[0116] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unitary claim, several devices, apparatuses or means can be listed, comprising means for carrying out a certain task. The use of the term "a" or "one" preceding these means does not exclude the use of a plurality of such means, but it is possible that the task is carried out by a single one of the means. The use of the terms "first", "second" and the like does not imply any order but is used for the purpose of naming.

[0117] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been described in detail in order to avoid obscuring the understanding of this description.

[0118] The foregoing detailed description has set forth various embodiments of the application via the use of specific terminology. However, embodiments thereof can be practiced without the specific details ("every" embodiment not being necessary for all uses or embodiments). In some instances, well-known methods, structures and techniques have not been described in detail in order to avoid obscuring aspects of the present application. It is contemplated that the principles and features described can be employed in a variety of embodiments and that those skilled in the art will recognize that the application can be practiced with modification and that the foregoing detailed description is to be regarded as merely illustrative. Accordingly, this description is to be construed as not limiting, but merely exemplary and illustrative.

Claims

1. A heat dissipation structure for a power module, wherein, include: Power module, heat dissipation layer and soldering layer; The power module includes a chip and a substrate; The chip is located on the substrate; The side of the substrate facing away from the chip is welded to the heat dissipation layer via the solder layer; The power module further includes an encapsulation layer; the encapsulation layer exposes at least a portion of the sidewall of the substrate, and the solder layer extends to the sidewall of the substrate exposed by the encapsulation layer.

2. The power module heat dissipation structure according to claim 1, wherein, The power module includes a first substrate and a second substrate; the chip is located between the first substrate and the second substrate; the heat dissipation layer includes a first heat dissipation layer and a second heat dissipation layer; the soldering layer includes a first soldering layer and a second soldering layer. The first substrate is soldered to the first heat dissipation layer via the first solder layer on the side opposite to the chip; the second substrate is soldered to the second heat dissipation layer via the second solder layer on the side opposite to the chip. The encapsulation layer exposes at least a portion of the sidewalls of the first liner and at least a portion of the sidewalls of the second liner, the first solder layer covers the sidewalls of the first liner exposed by the encapsulation layer, and the second solder layer covers the sidewalls of the second liner exposed by the encapsulation layer.

3. The power module heat dissipation structure according to claim 1 or 2, wherein, The power module's substrate includes a first metal layer, an insulating layer, and a second metal layer stacked together; the second metal layer is soldered onto the heat dissipation layer via the solder layer; the chip is located on the first metal layer. The encapsulation layer exposes at least a portion of the sidewall of the second metal layer, and the solder layer extends to the sidewall of the second metal layer exposed by the encapsulation layer.

4. The power module heat dissipation structure according to claim 3, wherein, The projections of the edges of the first metal layer and the second metal layer onto the insulating layer are located within the edges of the insulating layer.

5. The power module heat dissipation structure according to claim 3 or 4, wherein, The encapsulation layer covers the edge of the insulating layer.

6. The power module heat dissipation structure according to claim 2, wherein, A gasket is provided between the chip and the first substrate.

7. The power module heat dissipation structure according to any one of claims 1-6, wherein, The liner includes a direct copper-clad ceramic substrate or an active metal-welded ceramic substrate.

8. A vehicle, wherein, Includes the power module heat dissipation structure as described in any one of claims 1-7.

9. A packaging device for a power module heat dissipation structure, wherein, include: Encapsulation layer removal device for removing the encapsulation layer from at least a portion of the sidewalls of the substrate of a power module. A welding apparatus for welding the side of the substrate away from the chip of the power module to a heat dissipation layer via a welding layer, such that the welding layer extends to the sidewall of the substrate exposed by the encapsulation layer.

10. The packaging device for the power module heat dissipation structure according to claim 9, wherein, The encapsulation layer removal device includes a laser.

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