An IGBT module fixing structure on an electric heater PCBA electric control board

Abstract

The utility model relates to an IGBT module fixing structure on an electric heater PCBA electric control board, which is characterized by: multiple IGBT module pins are welded on the electric control board, and the bottom surface of the IGBT module is fitted with an insulating film; the insulating film is adhered to the surface of the main shell; a plurality of positioning holes are provided on the insulating shell, and two screw insertion holes are provided between the positioning holes; the insulating shell is buckled on the IGBT module from above, so that the plurality of positioning holes on the insulating shell and the plurality of IGBT modules are embedded and positioned one by one; an opening is provided on the IGBT fixing plate corresponding to each IGBT module, and a spring piece extending downward is connected to each opening on one side; the IGBT fixing plate is arranged above the insulating shell, and the IGBT fixing plate and the insulating shell are fixedly connected to the main shell by insertion screws, so that the lower ends of the plurality of spring pieces are respectively pressed and contacted with the upper ends of the plurality of IGBT modules. This structure improves the reliability of the installation of the IGBT module and improves the heat dissipation efficiency.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric device installation, and particularly relates to an IGBT module fixing structure on a PCBA electric control board of an electric heater. Background Art

[0002] New energy vehicles need to use electric heaters to provide heat for the cabin or adjust the temperature of the battery pack. At present, the heating system equipped in new energy vehicles is mainly high-voltage liquid heaters. The high-voltage liquid heater has electrical PCBA electronic control board (PCB), heating device and other components inside, which can be divided into two parts: electrical cavity and fluid cavity. Among them, the IGBT module is welded on the PCB, which mainly plays the role of switching the power supply on and off. When the high-voltage liquid heater is connected to the high voltage electricity and works normally, the IGBT will generate heat when it is turned on and off, causing the temperature of the module to rise. In order to ensure the normal operation of the IGBT module, it is very important to be able to dissipate heat effectively. Therefore, the IGBT is arranged on the outer surface of the fluid chamber of the main shell. The current IGBT installation method of the high-voltage liquid heater PCBA electronic control board is mainly to solder the pins on the PCB, and apply insulating thermal grease between the IGBT module and the main shell to dissipate heat for the IGBT module. However, there are the following shortcomings:

[0003] 1. The application of thermal grease is cumbersome and time-consuming;

[0004] 2. The thermal conductive silicone grease is easily lost after vibration, resulting in a short circuit between the IGBT element and the main housing, and the heater cannot work normally;

[0005] 3. There is a gap between the IGBT base and the main housing. After vibration, there is a risk of pin deformation or even falling off;

[0006] 4. The contact between the IGBT base and the main shell is insufficient, and the heat dissipation efficiency is low, which can easily lead to excessive IGBT temperature, frequent activation of control protection, and heater shutdown. Utility Model Content

[0007] In view of the deficiencies in the prior art, the utility model proposes an IGBT module fixing structure on an electric heater PCBA electric control board which has the advantages of simple structure, convenient installation, high reliability and guaranteed heat dissipation efficiency.

[0008] The above-mentioned purpose of the utility model is achieved through the following technical solutions

[0009] An IGBT module fixing structure on a PCBA electric control board of an electric heater, characterized in that: it comprises a main shell, a PCBA electric control board, a plurality of IGBT modules, an insulating shell, an insulating film and an IGBT fixing plate; a plurality of IGBT module pins are welded on the PCBA electric control board, the bottom surface of the IGBT module is made of an aluminum substrate, the bottom surface of the IGBT module is in contact with the insulating film, and the insulating film is adhered to the surface of the main shell; a plurality of positioning holes matching the number of IGBT modules are provided on the insulating shell, and two screw penetration holes are provided on the insulating shell between the positioning holes; the insulating shell is buckled and covered on the IGBT module from above, so that the plurality of positioning holes on the insulating shell and the plurality of IGBT modules form a one-to-one embedded positioning match;

[0010] The IGBT fixing plate adopts a U-shaped long groove plate, and an opening is provided on the IGBT fixing plate corresponding to each IGBT module, and a spring piece extending downward is connected to each opening on one side;

[0011] The IGBT fixing plate is arranged above the insulating shell, and the two screw penetration holes on the IGBT fixing plate are respectively aligned with the two screw penetration holes of the insulating shell and the two reserved threaded holes on the main shell along the upper and lower squares, and a fixed connection is formed by the penetration screws, so that the lower ends of the multiple springs on the IGBT fixing plate are respectively in top pressure contact with the upper ends of the multiple IGBT modules.

[0012] Furthermore, there are two rectangular heat dissipation platforms on the main housing which are in contact with the multiple IGBT modules, and the insulating film is adhered to the heat dissipation platforms.

[0013] Moreover, the IGBT fixing plate is a stamping structure, and the material is SUS301-H stainless steel.

[0014] Moreover, the main body of each spring piece adopts a bent structure, and the lower end of the spring piece adopts a concave arc shape.

[0015] Moreover, two positioning protrusions are symmetrically arranged in the middle position of the upper end of the insulating shell, and positioning grooves are arranged on the side of the two openings located in the middle of the IGBT fixing plate away from the connection with the spring sheet. The shapes of the two positioning grooves match the shapes of the two positioning protrusions on the insulating shell. The two positioning protrusions are respectively inserted into the two positioning grooves, so that the IGBT fixing plate and the insulating shell form a positioning fit.

[0016] The advantages and positive effects of the utility model are:

[0017] 1. The utility model adopts an elastic top pressure method to make the IGBT module fully contact with the main housing, and verifies through random vibration tests that the IGBT module structure is intact and the performance is normal.

[0018] 2. The end of the spring piece of the utility model adopts a bending structure, which has good flexibility and shock absorption functions, thereby preventing the impact force caused by vibration from damaging electrical components.

[0019] 3. The utility model realizes the integrated fixed connection of the PCBA electric control board, the insulating shell and the main shell through screws, and the lower end of the spring is pressed and contacted with the upper end of the IGBT module, which ensures that the pins and the surface of the IGBT module are evenly stressed, avoiding the bending and breaking of the pins due to vibration;

[0020] 4. The IGBT fixing plate of the utility model is made of SUS301-H material, which can avoid aging, rust and other problems and has a long service life;

[0021] 5. The utility model also has the advantages of simple structure and convenient installation and disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a three-dimensional exploded schematic diagram of the vehicle high-voltage electric heater assembly involved in the utility model;

[0023] Figure 2 It is a three-dimensional exploded view of the fixing structure of the IGBT module of the utility model;

[0024] Figure 3 This is a schematic diagram of the simulation model of the clamping force of the IGBT fixing plate of the utility model;

[0025] Figure 4 This is a schematic diagram of the structure of the insulation shell of the utility model Figure 1 ;

[0026] Figure 5 This is a schematic diagram of the structure of the insulation shell of the utility model Figure 2 :

[0027] Figure 6 This is a schematic diagram of the structure of the IGBT fixing plate of the utility model. Figure 1 ;

[0028] Figure 7 This is a schematic diagram of the structure of the IGBT fixing plate of the utility model. Figure 2 . DETAILED DESCRIPTION

[0029] The structure of the utility model is further described below with reference to the accompanying drawings and through embodiments. It should be noted that the embodiments are descriptive rather than restrictive.

[0030] An IGBT module fixing structure on an electric heater PCBA electric control board, see Figure 1-Figure 7It is used to fix the IGBT on the surface of the main housing to solve the defects of low heat dissipation efficiency and low vibration resistance of the IGBT. It also has the advantages of simple structure, easy installation and high reliability.

[0031] Vehicle high voltage electric heater assembly Figure 1 , mainly including the main housing 1, PCBA electric control board 2, insulating shell 3, IGBT fixing plate 4, top cover 5. Among them, the IGBT module 6 on the PCBA electric control board 2 is connected to the PCBA electric control board 2 by welding, and there is a layer of insulating film 7 between the IGBT module 6 and the main housing 1, which is pasted on the surface of the main housing 1 to play the role of insulation and heat conduction, see Figure 2 The IGBT fixing plate 4 is connected to the main housing 1 by bolts. The bent spring sheet structure of the IGBT fixing plate 4 fits tightly with the upper end of the IGBT module. A torque of 1.5 Nm is applied to the bolt 8 to make the spring sheet deform elastically by 1 mm. At this time, the spring sheet exerts a pressing force of about 100 N on the IGBT, which fits the bottom surface of the IGBT module tightly with the insulating film 7 on the surface of the main housing. The pressing force of 100 N generated by the deformation of the IGBT fixing plate spring sheet is obtained through CAE simulation analysis. The simulation model is shown in Figure 3 .

[0032] The main housing is made of die-cast aluminum. There are two smooth and flat rectangular heat dissipation platforms at the contact position between the main housing and the IGBT module. The length of the surface of each heat dissipation platform is 49 mm and the width is 25 mm.

[0033] The insulating shell is used to realize the positioning of multiple IGBT modules, and the insulating shell is provided with positioning holes 3.1 matching the number of IGBT modules, and two screw insertion holes 3.2 are provided between the positioning holes on the insulating shell.

[0034] The insulating shell is used to improve the insulation withstand voltage performance of the high-voltage liquid heater. By increasing the creepage distance between adjacent IGBT electronic components, the insulation withstand voltage is guaranteed to meet the customer's requirements for the insulation withstand voltage performance of the high-voltage liquid heater. This is mainly achieved in the following two aspects: First, the insulating shell is made of PPS-GF30 material, which can meet the requirements of the tracking index CTI>600V; second, the insulating shell structure between the two IGBTs is designed as a porous structure 3.4 to increase the creepage distance.

[0035] The IGBT fixing plate adopts a U-shaped long groove plate, which is formed by stamping. The material is SUS301-H stainless steel. An opening 4.1 is provided on the IGBT fixing plate corresponding to each IGBT module. A spring 4.2 extending downward is connected to each opening on one side. Furthermore, the main body of the spring adopts a bending structure, and the lower end of the spring adopts a concave arc shape. Two screw holes 4.3 are provided between the openings on the IGBT fixing plate. In the embodiment of the utility model, the spacing between the two screw holes is 53mm, and they are symmetrically distributed on the center line of the IGBT plane.

[0036] The pins of the IGBT module are welded on the PCBA electronic control board. The bottom surface of the IGBT is made of an aluminum substrate, and the bottom surface of the IGBT is bonded to the insulating film.

[0037] When assembling the PCBAPCBA electronic control board, the first step is to stick an insulating film on the smooth surface of the heat dissipation platform of the main shell; the second step is to install 6 M4 bolts to fix the PCBA board to the main shell; the third step is to buckle the insulating shell on the IGBT from above, so that the multiple positioning holes on the insulating shell form a one-to-one embedded positioning match with the multiple IGBT modules; the fourth step is to install the IGBT fixing plate above the insulating shell, so that the two screw penetration holes on the IGBT fixing plate are aligned with the two screw penetration holes of the insulating shell and the two reserved threaded holes on the main shell along the upper and lower squares. In order to achieve fast and accurate positioning of the insulating shell and the IGBT fixing plate, two positioning protrusions 3.3 are symmetrically arranged in the middle position of the upper end of the insulating shell, and positioning grooves 4.4 are arranged on the side of the two openings in the middle of the IGBT fixing plate away from the connection with the spring clip. The shapes of the two positioning grooves match the shapes of the two positioning protrusions on the insulating shell. The positioning grooves and the positioning protrusions are plugged into each other to achieve fast positioning of the IGB and the insulating shell. The fifth step is to install two screws on the IGB fixing plate, the insulating shell and the main shell respectively, and apply a torque of 0.9Nm to tighten them. The upper end of the IGB module is pressed by the spring clip on the IGB fixing plate to ensure that the IGBT fits tightly on the surface of the insulating film so that the IGBT can be fully dissipated.

[0038] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. An IGBT module fixing structure on an electric heater PCBA electric control board, characterized in that: It includes a main shell, a PCBA electric control board, multiple IGBT modules, an insulating shell, an insulating film and an IGBT fixing plate; multiple IGBT module pins are welded on the PCBA electric control board, the bottom surface of the IGBT module is made of an aluminum substrate, the bottom surface of the IGBT module is in contact with the insulating film, and the insulating film is adhered to the surface of the main shell; the insulating shell is provided with multiple positioning holes matching the number of IGBT modules, and two screw penetration holes are provided on the insulating shell between the positioning holes; the insulating shell is buckled onto the IGBT module from above, so that the multiple positioning holes on the insulating shell and the multiple IGBT modules form a one-to-one embedded positioning match; The IGBT fixing plate adopts a U-shaped long groove plate, and an opening is provided on the IGBT fixing plate corresponding to each IGBT module, and a spring piece extending downward is connected to one side of each opening; The IGBT fixing plate is arranged above the insulating shell, and the two screw penetration holes on the IGBT fixing plate are aligned with the two screw penetration holes of the insulating shell and the two reserved threaded holes on the main shell along the upper and lower squares, and a fixed connection is formed by the penetration screws, so that the lower ends of the multiple springs on the IGBT fixing plate are respectively in top pressure contact with the upper ends of the multiple IGBT modules.

2. The IGBT module fixing structure on the electric heater PCBA electric control board according to claim 1 is characterized in that: There are two rectangular heat dissipation platforms on the main shell body at the positions in contact with the multiple IGBT modules, and the insulating film is adhered to the heat dissipation platforms.

3. The IGBT module fixing structure on the electric heater PCBA electric control board according to claim 1 is characterized in that: The IGBT fixing plate is a stamping structure, and the material is SUS301-H stainless steel.

4. The IGBT module fixing structure on the electric heater PCBA electric control board according to claim 1 is characterized in that: The main body of each spring piece adopts a bent structure, and the lower end of the spring piece adopts a concave arc shape.

5. The IGBT module fixing structure on the electric heater PCBA electric control board according to claim 1, characterized in that: Two positioning protrusions are symmetrically arranged in the middle position of the upper end of the insulating shell, and positioning grooves are arranged on the side of the two openings located in the middle of the IGBT fixing plate away from the connection with the spring sheet. The shapes of the two positioning grooves match the shapes of the two positioning protrusions on the insulating shell. The two positioning protrusions are respectively inserted into the two positioning grooves, so that the IGBT fixing plate and the insulating shell form a positioning fit.

Images