Crimping IGBT device sub-module and crimping IGBT device

Abstract

The invention discloses a crimped IGBT device sub-module and a crimped IGBT device, and belongs to the technical field of power transmission equipment, the crimped IGBT device sub-module comprises IGBT chips arranged in an array, a mounting space for gas filling is arranged between every two adjacent IGBT chips, and the mounting space is arranged between the two adjacent IGBT chips. The installation distance between two adjacent columns of IGBT chips and the installation distance between two adjacent rows of IGBT chips can form an accommodating space for accommodating a single IGBT chip. The crimping IGBT device comprises a plurality of crimping IGBT device sub-modules which are arranged in parallel. The gas in the installation space can increase the mutual thermal resistance between the chips, reduce the thermal coupling effect of the chips connected in parallel, further reduce the junction temperature of the chips and improve the operation reliability of the device, and the containing space formed by the installation space enables the IGBT chips to be arranged in a distributed mode, so that the heat conduction path between the chips can be improved, the heat transfer efficiency is improved, and the reliability of the device is improved. And the phenomenon of local overheating is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission equipment, and particularly relates to a press-fit IGBT device sub-module and a press-fit IGBT device. Background Art

[0002] With the rapid development of power electronics technology, especially the development of the fully controlled device IGBT (Insulated Gate Bipolar Transistor), the flexible DC transmission technology has become a new generation of DC transmission technology in today's society. The flexible DC transmission technology is a high-voltage DC transmission technology based on a voltage source converter. The two most core power electronic devices are a high-voltage DC circuit breaker and a flexible DC converter valve. Among them, the IGBT device applied in the flexible DC converter valve mainly bears a complex electrical stress condition of the superposition of alternating current and direct current, so higher requirements are put forward for the reliability of the device.

[0003] In the flexible DC transmission technology, the press-fit IGBT has realized advantages such as double-sided heat dissipation, easy series connection, and short circuit in case of failure with its unique packaging form, and is gradually becoming the mainstream in flexible DC transmission. Due to the mutual coupling effect of the electromagnetic field, temperature field and structural field inside the press-fit IGBT device, the multi-physical field environment inside it is extremely complex, which in turn leads to the uneven thermal distribution among the parallel chips inside the device. Under long-term operating conditions, the weak links will fail first. Therefore, it is very important to balance the thermal distribution of the parallel chips inside the device for the safe and reliable operation of the device.

[0004] Currently, the research direction of the method for balancing the thermal distribution of multiple chips of press-fit IGBT mainly focuses on aspects such as the materials and dimensions of the device, and there are few new breakthroughs. Summary of the Invention

[0005] The purpose of the present invention is to solve the above technical problems, and provide a press-fit IGBT device sub-module and a press-fit IGBT device. The gas within the installation spacing can increase the mutual thermal resistance between the chips, reduce the thermal coupling effect of each parallel chip, thereby reducing the chip junction temperature and improving the reliability of the device operation. And the accommodation space formed by the installation spacing makes the IGBT chips arranged in a decentralized manner, optimizing the layout of the chips, improving the heat conduction path between the chips, increasing the heat transfer efficiency, and avoiding the phenomenon of local overheating.

[0006] To achieve the above object, the present invention provides the following solutions: The present invention discloses a press-fit IGBT device sub-module, which includes IGBT chips arranged in an array. There is an installation spacing for gas filling between two adjacent IGBT chips, and the installation spacing between two adjacent columns of IGBT chips and the installation spacing between two adjacent rows of IGBT chips can form an accommodation space for accommodating a single IGBT chip.

[0007] In one embodiment, the number of columns and rows of the IGBT chips is odd and the same, and the number of IGBT chips from the first column to the last column alternates between 2n and 2n - 1 in sequence, where n is a natural number.

[0008] In one embodiment, the number of IGBT chips is eight.

[0009] In one embodiment, it further includes an emitter copper plate and a collector molybdenum plate. The IGBT chips are installed between the emitter copper plate and the collector molybdenum plate, and the collector molybdenum plate is provided with a cooling channel for the coolant to pass through.

[0010] In one embodiment, the cooling channel is a rectangular channel.

[0011] In one embodiment, the area of the cross-section of the cooling channel is increased in the region close to the IGBT chips.

[0012] In one embodiment, the IGBT chip includes a steel disc spring, a copper column, an aluminum sheet, a molybdenum sheet, a thermal conductive gasket, and a silicon chip stacked in sequence. The steel disc spring is connected to the emitter copper plate, and the silicon chip is connected to the collector molybdenum plate.

[0013] In one embodiment, the thermal conductive gasket is made of graphene material.

[0014] In one embodiment, the thickness of the thermal conductive gasket is 0.01 mm.

[0015] It also discloses a press-fit IGBT device, which includes a plurality of the above-mentioned press-fit IGBT device sub-modules arranged in parallel.

[0016] The present invention has achieved the following technical effects compared with the prior art:

[0017] In the present invention, by setting an installation spacing for filling gas between the IGBT chips, the gas in the installation spacing can increase the mutual thermal resistance between the chips, reduce the thermal coupling effect of each parallel chip, thereby reducing the chip junction temperature and improving the reliability of the device operation; at the same time, the accommodation space formed by the installation spacing makes the IGBT chips arranged in a decentralized manner, optimizing the chip layout, improving the heat conduction path between the chips, increasing the heat transfer efficiency, and avoiding the phenomenon of local overheating.

[0018] The following technical effects are also achieved by other technical solutions of the present invention compared with the prior art:

[0019] 1. By providing a cooling channel on the collector molybdenum plate, the heat of the IGBT chip can be quickly removed.

[0020] 2. The cooling channel is a rectangular channel. On the one hand, it can ensure the smooth flow of the coolant. On the other hand, compared with other shaped channels such as circular channels, it makes full use of the space of the collector molybdenum plate and can increase the heat dissipation area.

[0021] 3. The area of the cross-section of the cooling channel in the area close to the IGBT chip is increased. On the premise of ensuring the coolant flow rate, the heat dissipation area of the area with concentrated heat generation is increased, the local heat dissipation efficiency is improved, and the heat distribution is further optimized.

[0022] 4. The thermal conductive gasket is arranged between the molybdenum sheet and the silicon chip to fill the tiny gap between the two, which can improve the heat transfer efficiency, improve the lateral heat dissipation of local hot spots, is conducive to reducing the temperature of the IGBT chip, and improves the reliability of the device.

[0023] 5. The thermal conductive gasket is made of graphene material, which has high thermal conductivity and good flexibility. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 is a schematic three-dimensional structure diagram of a press-fit IGBT device sub-module in an embodiment of the present invention;

[0026] Figure 2 is a schematic side view structure diagram of a press-fit IGBT device sub-module in an embodiment of the present invention;

[0027] Figure 3 is a schematic three-dimensional structure diagram of a press-fit IGBT device sub-module (without emitter copper plate) in an embodiment of the present invention;

[0028] Figure 4 is a schematic top view structure diagram of a press-fit IGBT device sub-module (without emitter copper plate) in an embodiment of the present invention;

[0029] Figure 5 is Figure 2 a schematic diagram of a partially enlarged structure in

[0030] Figure 6 is Figure 3 a partially enlarged structural schematic diagram in

[0031] Figure 7 a cross-sectional structural schematic diagram of a press-fit IGBT device sub-module (including a variable cross-section cooling channel) in an embodiment of the present invention;

[0032] Figure 8 a cross-sectional structural schematic diagram of a cooling channel with a variable cross-section in an embodiment of the present invention;

[0033] Figure 9 a three-dimensional structural schematic diagram of the connection between a silicon chip and a heat-conducting gasket in an embodiment of the present invention;

[0034] Figure 10 a top-view structural schematic diagram of the connection between a silicon chip and a heat-conducting gasket in an embodiment of the present invention;

[0035] Figure 11 is a schematic diagram of the arrangement of traditional IGBT chips;

[0036] Figure 12 is a schematic diagram of the arrangement of IGBT chips in an embodiment of the present invention;

[0037] Figure 13 is a schematic diagram for comparing the maximum junction temperatures of the IGBT chips of the present invention and traditional IGBT chips.

[0038] Explanation of reference numerals: 1. Emitter copper plate; 2. Steel disc spring; 3. Copper column; 4. Aluminum sheet; 5. Molybdenum sheet; 6. Heat-conducting gasket; 7. Silicon chip; 8. Collector molybdenum plate; 9. Cooling channel. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0040] The purpose of the present invention is to provide a press-fit IGBT device sub-module and a press-fit IGBT device to solve the problems existing in the prior art, increase the mutual thermal resistance between IGBT chips, weaken the thermal coupling effect between IGBT chips, enable heat to be more efficiently transferred to the heat dissipation structure through the electrodes, reduce the temperature of the IGBT chips, improve the reliability of the device, improve the heat conduction path between the chips, increase the heat transfer efficiency, and avoid the phenomenon of local overheating.

[0041] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Embodiment 1

[0043] As Figures 1 to 13 shown, this embodiment provides a press-fit IGBT device sub-module, including IGBT chips arranged in an array. There is an installation spacing for filling with gas (air or other gas) between adjacent two IGBT chips. The installation spacing between adjacent two columns of IGBT chips and the installation spacing between adjacent two rows of IGBT chips can form an accommodation space. The size of this accommodation space can allow a single IGBT chip to be accommodated, that is, the distance of one IGBT chip is removed between adjacent two columns and adjacent two rows of IGBT chips, so that the layout of each parallel IGBT chip is relatively dispersed. Under the action of gas between the IGBT chips, the mutual thermal resistance between the IGBT chips can be increased, the thermal coupling effect between the chips can be weakened, and heat can be transferred to the heat dissipation structure more efficiently through the electrodes, which is beneficial to reducing the temperature of the IGBT chips and improving the reliability of the press-fit IGBT device. This is because the thermal conductivity of gas is much smaller than that of solid, and compared with complete contact with the solid surface, additional transfer resistance is increased.

[0044] For the traditional press-fit IGBT device sub-module, as Figure 11 shown, the layout of each parallel chip is relatively compact. Through the thermal-structural coupling analysis software comsol to analyze this device, the chips numbered 2, 4, 9, and 11 in the figure are strongly affected by the thermal coupling of the surrounding chips, and their junction temperatures are relatively high. While the press-fit IGBT device sub-module in this embodiment adopts a dispersed layout method. By optimizing the chip layout method, the heat conduction path between the chips can be improved, the heat transfer efficiency can be increased, and the phenomenon of local overheating can be avoided. At the same time, according to the thermal network model of the press-fit IGBT and combined with the relevant knowledge of heat transfer, improving the layout method between the device chips is beneficial to increasing the mutual thermal resistance between the chips, weakening the mutual influence of the chip temperatures, being beneficial to reducing the chip temperature, and improving the reliability of the device.

[0045] In an embodiment, both the number of columns and the number of rows of the IGBT chips are odd and the same. The number of IGBT chips from the first column to the last column alternates between 2n and 2n - 1 in turn, where n is a natural number.

[0046] In one embodiment, through the thermo-mechanical multi-physics analysis of a press-fit IGBT device with 4500V and 3000A, the key chips with strong internal thermal coupling effects were found. Based on this, the IGBT chips of the 4500V and 3000A elastic press-fit IGBT device were planned. Specifically, the number of IGBT chips in the 4500V and 3000A press-fit IGBT device is eight. The layout of these eight IGBT chips was planned. Among them, the eight IGBT chips are arranged in five rows and five columns. From the first column to the last column, there are two IGBT chips and three IGBT chips alternating with each other. Correspondingly, from the first row to the last row, there are also two IGBT chips and three IGBT chips alternating with each other. Refer to Figure 4 and Figure 11 As shown, from left (the first column) to right (the last column): there are two IGBT chips, three IGBT chips, two IGBT chips, three IGBT chips, and two IGBT chips in sequence.

[0047] The traditional press-fit IGBT device sub-module with eight IGBT chips and the press-fit IGBT device sub-module with eight IGBT chips in this embodiment were compared through simulation analysis and junction temperature comparison:

[0048] First, through the thermo-mechanical coupling analysis of the device using the Comsol simulation analysis software, it was found that for the traditional 4500V and 3000A press-fit IGBT device, the four chips numbered two, four, nine, and eleven are strongly affected by the thermal coupling of the surrounding chips, and their junction temperatures are relatively high. Then, through Comsol simulation analysis, the path one before improvement, path two and path three after improvement were respectively extracted, and the highest junction temperature distribution of chips one, two, three, four, and five before and after improvement was obtained. As Figure 13 shown, it can be clearly seen that by changing the arrangement of the IGBT chips, the junction temperature of the IGBT chips has been significantly reduced, from 408K to 392K.

[0049] In one embodiment, it also includes an emitter copper plate 1 and a collector molybdenum plate 8. The IGBT chips are installed between the emitter copper plate 1 and the collector molybdenum plate 8. The collector molybdenum plate 8 is provided with cooling channels 9 for the coolant to pass through, and the cooling channels 9 are arranged with a certain spacing. The number and spacing of the cooling channels 9 are set according to needs. After the coolant is introduced into the cooling channels 9, a large amount of heat can be carried away, further reducing the heat of the chips.

[0050] In one embodiment, the cooling channels 9 are rectangular channels. The rectangular channels can ensure the smooth flow of the coolant and carry away a large amount of heat. Compared with circular channels, they can maximize the use of the space of the collector molybdenum plate 8 and increase the heat dissipation area.

[0051] In one embodiment, the cooling channel 9 is designed with a variable cross-section. In the heat-concentrated area of the cooling channel 9 near the IGBT chip 2, the cross-sectional area of the cooling channel 9 is appropriately increased, such as increasing the width and height, while maintaining the original size in the area far from the heat source. Refer to Figure 7 and Figure 8 As shown. On the premise of ensuring the coolant flow rate, the heat dissipation area in the heat-concentrated area is increased, the local heat dissipation efficiency is improved, and the heat distribution is further optimized.

[0052] In one embodiment, the thickness of the collector molybdenum plate 8 is 6 mm, which can effectively increase the heat capacity, make the heat more stable during the conduction process, and reduce local hot spots. When the cooling channel 9 is a rectangular channel, the width of the cooling channel 9 is 1.6 mm, the height of the cooling channel 9 is 2 mm, and the spacing of the cooling channels 9 is 17 mm, with a total of 5 groups. Such a size design of the cooling channel 9 can not only ensure the smooth flow of the coolant and take away a large amount of heat, but also maximize the use of the space of the collector molybdenum plate 8 to increase the heat dissipation area. If the cooling channel 9 is designed with a variable cross-section, then in the heat-concentrated area near the IGBT chip 2, the width of the cooling channel 9 is increased to 2 mm and the height is increased to 2.4 mm, while maintaining the original size in the area far from the heat source.

[0053] In one embodiment, the IGBT chip includes a steel disc spring 2, a copper column 3, an aluminum sheet 4, a molybdenum sheet 5, a thermal conductive gasket 6, and a silicon chip 7 stacked in sequence. The steel disc spring 2 is connected to the emitter copper plate 1, and the silicon chip 7 is connected to the collector molybdenum plate 8. The contact thermal resistance of the press-pack IGBT device accounts for about 50% of the total thermal resistance. Therefore, a thermal conductive gasket 6 is provided and arranged between the molybdenum sheet 5 and the silicon chip 7 to fill the tiny gap between the two, which can reduce the contact thermal resistance between the elastomer and the IGBT module in the press-pack IGBT device, improve the heat transfer efficiency, improve the lateral heat dissipation of local hot spots, facilitate reducing the temperature of the IGBT chip, and improve the reliability of the device.

[0054] In one embodiment, the thermal conductive gasket 6 is made of graphene material. Graphene material has high thermal conductivity and good flexibility.

[0055] In one embodiment, the thickness of the thermal conductive gasket 6 is 0.01 mm. The graphene thermal conductive gasket 6 has a size equivalent to the active area size of the silicon chip 7. On the surface of the active area of the silicon chip 7, with a thickness of 0.01 mm, it can fill the tiny gap and improve the lateral heat dissipation of local hot spots. Through analysis by the Comsol simulation analysis software, it is found that the peak temperature on the surface of the IGBT chip before and after the improvement drops from 392 K to 390 K, with a decrease of 2 K.

[0056] Example 2

[0057] As Figures 1 to 13As shown in the figure, this embodiment provides a press-fit IGBT device, which includes a plurality of press-fit IGBT device sub-modules in Embodiment 1 arranged in parallel.

[0058] In one embodiment, it includes six press-fit IGBT device sub-modules arranged in parallel.

[0059] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A crimped IGBT device sub-module, characterized in that: It comprises IGBT chips arranged in an array, wherein there is a mounting spacing for gas filling between two adjacent IGBT chips, and the mounting spacing between two adjacent columns of IGBT chips and the mounting spacing between two adjacent rows of IGBT chips can form a accommodating space for accommodating a single IGBT chip.

2. The crimped IGBT device sub-module according to claim 1, characterized in that: The number of columns and rows of the IGBT chips are both odd numbers and the same in number. The number of the IGBT chips from the first column to the last column is alternately 2n and 2n-1, where n is a natural number.

3. The crimped IGBT device sub-module according to claim 2, characterized in that: The number of the IGBT chips is eight.

4. The crimped IGBT device sub-module according to any one of claims 1 to 3, characterized in that: It also includes an emitter copper plate and a collector molybdenum plate, the IGBT chip is mounted between the emitter copper plate and the collector molybdenum plate, and the collector molybdenum plate is provided with a cooling channel for cooling liquid to pass through.

5. The crimped IGBT device sub-module according to claim 4, characterized in that: The cooling channel is a rectangular channel.

6. The crimped IGBT device sub-module according to claim 5, characterized in that: The cross-sectional area of ​​the cooling channel is increased in a region close to the IGBT chip.

7. The crimped IGBT device sub-module according to claim 4, characterized in that: The IGBT chip comprises a steel disc spring, a copper column, an aluminum sheet, a molybdenum sheet, a thermally conductive gasket and a silicon chip which are connected in sequence. The steel disc spring is connected to the emitter copper plate, and the silicon chip is connected to the collector molybdenum plate.

8. The crimped IGBT device sub-module according to claim 7, characterized in that: The thermally conductive pad is made of graphene material.

9. The crimped IGBT device sub-module according to claim 8, characterized in that: The thickness of the thermally conductive pad is 0.01 mm.

10. A crimped IGBT device, characterized in that: It comprises a plurality of press-fit IGBT device sub-modules as described in any one of claims 1 to 9 which are arranged in parallel.

Images