Power module and electric drive assembly

Abstract

The utility model provides a power module and an electric drive assembly. The power module comprises a plurality of chips, a plurality of copper bars, a first substrate and a vapor chamber. The plurality of chips are fixed with the first substrate in a silver sintering manner, so that excellent electric conduction and heat conduction properties are achieved, the fatigue effect is avoided, and the power cycle index and the reliability of the electric drive assembly are improved; the plurality of chips are arranged on the first substrate in pairs, and the plurality of copper bars are electrically connected with the two chips in one group respectively, so that the connection resistance between the chips is reduced, higher current magnitude and better heat-conducting property are synchronously obtained, and the power cycle index of the electric drive assembly and the heat distribution of the chips are improved. The vapor chamber is in heat conduction with the first substrate, so that heat generated by the chip is conducted to the vapor chamber through the first substrate, the heat conductivity coefficient is increased, and the heat conduction capability is improved. According to the power module and the electric drive assembly, the current output capacity under the same parallel chip condition is improved, the power density and reliability of the power module are improved, and the service life of the power module is prolonged.

Description

Technical Field

[0001] The present application relates to the field of power modules, and in particular to power modules and electric drive assemblies. Background Art

[0002] The power module is a key component in the electric drive system, responsible for high-power electric energy conversion. The power module has a decisive influence on the performance, efficiency, cost, safety and reliability of the electric drive system and even the vehicle. The chip and substrate of the power module on the market are currently fixed by welding, which is prone to fatigue effect in soft lead connection; and most of the chips are connected by bonding wires, the connection resistance between the chips is large, the current is low, and the thermal conductivity is poor; at the same time, the thermal conductivity between the substrates is small, and the heat conduction capacity is poor, which affects the power density of the power module. Utility Model Content

[0003] The present application provides a power module and an electric drive assembly that can improve power density.

[0004] A power module comprises: a plurality of chips, a plurality of copper bars, a first substrate and a temperature averaging plate, wherein the plurality of chips are fixed to the first substrate by silver sintering, the plurality of chips are arranged in groups of two on the first substrate, the plurality of copper bars are electrically connected to two chips in a group respectively, and the temperature averaging plate is thermally conductive with the first substrate so that the heat generated by the chips is conducted to the temperature averaging plate via the first substrate.

[0005] Furthermore, the temperature homogenizing plate is fixed to the first substrate by welding.

[0006] Furthermore, the first substrate includes a ceramic plate and a first copper layer and a second copper layer disposed on opposite sides of the ceramic plate, the chip is fixed to the first copper layer by silver sintering, and the second copper layer is fixed to the temperature equalizing plate by welding.

[0007] Furthermore, the power module includes a second substrate, the temperature averaging plate is located between the first substrate and the second substrate, and the temperature averaging plate and the second substrate are thermally conductive.

[0008] Furthermore, the second substrate is provided with a heat dissipation channel, and the temperature homogenizing plate is located between the heat dissipation channel and the first substrate.

[0009] Furthermore, the temperature homogenizing plate is fixed to the second substrate by welding.

[0010] Furthermore, the second substrate is provided with a mounting hole, and the temperature homogenizing plate is located in the mounting hole.

[0011] Furthermore, the temperature homogenizing plate is integrally provided with the second substrate.

[0012] Furthermore, the first substrate and the temperature homogenizing plate are both provided in plurality, and the plurality of first substrates are arranged in sequence along the length direction of the second substrate.

[0013] An embodiment of the present application also provides an electric drive assembly, including the above-mentioned power module.

[0014] In some embodiments, the chip of the above technical solution is fixed to the first substrate by silver sintering, so that the chip and the first substrate have excellent electrical and thermal conductivity, avoiding fatigue effect, and improving the power cycle number and reliability of the electric drive assembly; using copper busbars for connection reduces the connection resistance between the copper busbars and the chip, and can simultaneously obtain higher current and better thermal conductivity, thereby improving the power cycle number of the electric drive assembly and the thermal distribution of the chip; the setting of the temperature equalizing plate improves the thermal conductivity and the heat conduction capacity. The power module and electric drive assembly of the present application not only improve the output current capacity under the same parallel chip conditions, but also improve the power density, reliability and life of the power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of a power module after packaging according to an exemplary embodiment of the present application.

[0016] Figure 2 yes Figure 1 An exploded view of the power module is shown.

[0017] Figure 3 yes Figure 2 The schematic diagram shows a power module chip, a copper bus, a first substrate and a temperature vapor chamber after being fixed.

[0018] Figure 4 yes Figure 1 A three-dimensional view of a power module is shown, wherein the unpackaged portion of the power module is displayed.

[0019] Explanation of the accompanying drawings: 1. chip; 2. copper busbar; 3. first substrate; 31. first copper layer; 32. ceramic plate; 33. second copper layer; 4. temperature balancing plate; 5. second substrate; 51. mounting hole; 6. housing; 7. output terminal; 8. solder sheet; 9. heat dissipation part. DETAILED DESCRIPTION

[0020] An embodiment of the present application provides an electric drive assembly, including a power module.

[0021] See also Figures 1 to 3As shown, the power module includes multiple chips 1, multiple copper bars 2, a first substrate 3 and a temperature-averaging plate 4. The multiple chips 1 are fixed to the first substrate 3 by silver sintering. The multiple chips 1 are arranged in groups of two on the first substrate 3. The multiple copper bars 2 are electrically connected to two chips 1 in a group respectively. The temperature-averaging plate 4 is thermally conductive with the first substrate 3 so that the heat generated by the chip 1 is transferred to the temperature-averaging plate 4 via the first substrate 3.

[0022] Heat conduction between the temperature homogenizing plate 4 and the first substrate 3 can be achieved through direct contact or indirect contact.

[0023] Multiple chips 1 are fixed to the first substrate 3 by silver sintering. Silver sintering is to coat silver powder on the chip 1 and / or the first substrate 3, and sinter the chip 1 and the first substrate 3 in a high-temperature and high-pressure welding furnace. Silver sintering has good electrical and thermal conductivity, and will not have fatigue effects in soft lead connections, thereby improving the power cycle times and reliability of the electric drive assembly.

[0024] Multiple copper busbars 2 are electrically connected to two chips 1 in a group respectively. The setting of the copper busbars 2 can reduce the connection resistance between the chips 1, and simultaneously obtain higher current and better thermal conductivity, thereby improving the number of cycles of the entire electric drive assembly and the heat distribution of the chip 1.

[0025] See also Figure 2 and 3 As shown, the temperature plate 4 and the first substrate 3 are thermally conductive, so that the heat generated by the chip 1 is conducted to the temperature plate 4 via the first substrate 3. The thermal conductivity of the temperature plate 4 is between 10000W / mK and 20000W / mK (watts per meter Kelvin). Compared with the traditional copper plate, the thermal conductivity of the temperature plate 4 is increased, the thermal conductivity of the power module is improved, and the heat generated by the chip 1 is more evenly dispersed to avoid local overheating, thereby increasing the service life of the chip 1.

[0026] In this embodiment, the temperature averaging plate 4 is fixed to the first substrate 3 by welding, and the welding connection can ensure a stable connection between the temperature averaging plate 4 and the first substrate 3, thereby enhancing the reliability of the overall structure.

[0027] In some embodiments, a solder sheet 8 is disposed between the temperature averaging plate 4 and the first substrate 3 , and the solder sheet 8 is melted to fix the temperature averaging plate 4 and the first substrate 3 .

[0028] In some embodiments, a positioning structure may be provided between the temperature homogenizing plate 4 and the first substrate 3 to achieve a fixed connection by mechanical pressing.

[0029] In some implementations, a thermally conductive adhesive with high thermal conductivity may also be used to bond and fix the temperature homogenizing plate 4 to the first substrate 3 .

[0030] In some embodiments, the temperature homogenizing plate 4 and the first substrate 3 may be fixed by bolts, rivets, or snaps.

[0031] In some embodiments, the first substrate 3 includes a ceramic plate 32 and a first copper layer 31 and a second copper layer 33 disposed on opposite sides of the ceramic plate 32, the chip 1 and the first copper layer 31 are fixed by silver sintering, and the second copper layer 33 is fixed by welding to the temperature averaging plate 4. The first substrate 3 is fixed to the chip 1 and the temperature averaging plate 4 by the first copper layer 31 and the second copper layer 33, thereby improving the overall heat conduction efficiency of the power module.

[0032] In some embodiments, the first substrate 3 may also be a metal substrate, such as an aluminum alloy substrate or a copper substrate.

[0033] In some embodiments, the first substrate 3 may also be a composite substrate, such as a ceramic aluminum-clad substrate, a ceramic copper-nickel composite substrate, a ceramic graphite composite substrate, and the like.

[0034] The power module includes a second substrate 5. The temperature averaging plate 4 is located between the first substrate 3 and the second substrate 5. The temperature averaging plate 4 and the second substrate 5 are heat-conducted. The temperature averaging plate 4 and the second substrate 5 can be in direct or indirect contact to achieve heat conduction.

[0035] In some embodiments, the temperature homogenizing plate 4 and the second substrate 5 are fixed by welding.

[0036] Optionally, the temperature homogenizing plate 4 and the second substrate 5 may be connected by bolt fixing, snap fixing, adhesive fixing, or the like.

[0037] In some embodiments, the temperature homogenizing plate 4 and the second substrate 5 are integrally provided.

[0038] In some embodiments, the second substrate 5 is provided with a mounting hole 51 , and the temperature homogenizing plate 4 is located in the mounting hole 51 .

[0039] The temperature equalizer 4 is pressed into the mounting hole 51 of the second substrate 5, with a simple structure and easy installation; the temperature equalizer 4 is located between the first substrate 3 and the second substrate 5, forming a good heat conduction path, reducing mechanical deformation and material aging caused by temperature differences, and improving the service life and reliability of the entire power module.

[0040] The second substrate 5 is provided with a heat dissipation channel (not shown), and the temperature averaging plate 4 is located between the heat dissipation channel and the first substrate 3. The heat dissipation channel can guide and enhance the convective heat transfer process, promote the rapid discharge of heat, and improve the heat dissipation efficiency of the second substrate 5. The temperature averaging plate 4 is located between the heat dissipation channel and the first substrate 3 to avoid heat confinement on the first substrate 3 and ensure that the heat of the first substrate 3 can be fully transferred to the heat dissipation channel through the temperature averaging plate 4.

[0041] The power module further includes a heat dissipation portion 9 , which is located below the second substrate 5 . The heat dissipation portion 9 can effectively expand the heat dissipation area of ​​the second substrate 5 and improve the heat dissipation efficiency.

[0042] Optionally, there are multiple heat dissipation parts 9 , and the multiple heat dissipation parts 9 are evenly arranged on the second substrate 5 .

[0043] In some embodiments, the heat dissipation portion 9 may be formed of uniformly arranged copper pin fins, heat sinks, heat pipe elements, etc.

[0044] exist Figure 2 In the embodiment, the first substrate 3 and the temperature equalizing plate 4 are both provided in plurality, and the plurality of first substrates 3 are sequentially arranged along the length direction of the second substrate 5 .

[0045] In this embodiment, there are three first substrates 3 and three temperature averaging plates 4 , and the three first substrates 3 are arranged in sequence along the length direction of the second substrate 5 , which is beneficial to the processing and manufacturing of the temperature averaging plates 4 and their fixation to the second substrate 5 .

[0046] In some implementations, only one temperature homogenizing plate 4 may be provided.

[0047] exist Figure 2 In the embodiment, the power module includes thirty-six chips 1, three first substrates 3 and eighteen copper bars 2. Every twelve chips 1 are evenly arranged in groups of two on one first substrate 3, and one copper bar 2 is electrically connected to two chips 1 in one group. The present application does not limit the number of chips 1, the number of copper bars 2 and the number of first substrates 3.

[0048] See also Figure 4 As shown, the power module further includes: a plurality of output terminals 7 , the output terminals 7 are arranged on the first substrate 3 , and the output terminals 7 are electrically connected to the copper bus 2 through the first substrate 3 .

[0049] In some embodiments, the output terminal 7 may be a copper terminal, a gold-plated terminal, an aluminum terminal, or the like.

[0050] See also Figure 1 The power module further includes a shell 6 , which is integrally injection molded to enclose the chip 1 , the copper bus 2 , the first substrate 3 , and the temperature balancing plate 4 in the shell 6 .

[0051] In some embodiments, the shell 6 is made of plastic material, and the plastic material may be engineering plastics with high heat resistance such as PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), PPA (polyphenylene sulfide), PA (polyamide), LCP (liquid crystal polymer), etc.

Claims

1. A power module, characterized in that: include: A plurality of chips, a plurality of copper bars, a first substrate and a temperature averaging plate, wherein the plurality of chips are fixed to the first substrate by silver sintering, the plurality of chips are arranged in groups of two on the first substrate, the plurality of copper bars are electrically connected to two chips in a group respectively, and the temperature averaging plate and the first substrate are thermally conductive, so that the heat generated by the chips is transferred to the temperature averaging plate via the first substrate.

2. The power module according to claim 1, characterized in that: The temperature homogenizing plate is fixed to the first substrate by welding.

3. The power module according to claim 2, characterized in that: The first substrate includes a ceramic plate and a first copper layer and a second copper layer arranged on opposite sides of the ceramic plate. The chip is fixed to the first copper layer by silver sintering, and the second copper layer is fixed to the temperature equalizing plate by welding.

4. The power module according to any one of claims 1 to 3, characterized in that: The power module includes a second substrate. The temperature evaporator is located between the first substrate and the second substrate. The temperature evaporator and the second substrate are thermally conductive.

5. The power module according to claim 4, characterized in that: The second substrate is provided with a heat dissipation channel, and the temperature homogenizing plate is located between the heat dissipation channel and the first substrate.

6. The power module according to claim 4, characterized in that: The temperature homogenizing plate is fixed to the second substrate by welding.

7. The power module according to claim 6, characterized in that: The second substrate is provided with a mounting hole, and the temperature equalizing plate is located in the mounting hole.

8. The power module according to claim 4, characterized in that: The temperature homogenizing plate is integrally arranged with the second substrate.

9. The power module according to claim 4, characterized in that: The first substrate and the temperature homogenizing plate are both provided in plurality, and the plurality of first substrates are arranged in sequence along the length direction of the second substrate.

10. An electric drive assembly, characterized in that: Comprising the power module according to any one of claims 1 to 9.

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