Step relief pressure explosion-proof tube shell and power module

Abstract

The application discloses a hierarchical pressure relief explosion-proof tube shell and a power module. The hierarchical pressure relief explosion-proof tube shell comprises a shell body adapted to be arranged outside a chip and connected with a substrate, wherein a relief channel and an explosion relief channel are arranged on the shell body and respectively communicate with an inner cavity of the shell body; the shell body is further provided with a bursting piece connected to the shell body and used for plugging the explosion relief channel; when the pressure in the inner cavity of the shell body is lower than a first pressure threshold, the relief channel can perform primary pressure relief on the inner cavity of the shell body; when the pressure in the inner cavity of the shell body is increased to the first pressure threshold, the bursting piece fails to be connected with the shell body and opens the explosion relief channel, so that secondary pressure relief is performed on the inner cavity of the shell body. The relief channel on the shell body and the bursting piece can sequentially release high-pressure gas and energy in the shell body in stages, so that different pressure relief requirements of the inner cavity of the shell body are met, the active pressure relief capacity of the tube shell is improved, and the shell body of the tube shell is prevented from being broken or plastically deformed as a whole under pressure.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power module technology, and particularly to a graded pressure relief explosion-proof housing and power module. Background Technology

[0002] High-voltage power modules, as a key technology driving technological innovation in modern rail transit, primarily undertake the core tasks of power conversion and control in rail transit. A high-voltage power module is a compact and high-performance modular unit that integrates multiple high-power semiconductor chips (such as IGBTs), drive components, protection components, sensing components, and passive components into a single package.

[0003] In high-voltage rail transit, power modules are prone to secondary turn-on failures, manifesting as a chain reaction from electrical failure to physical explosion. The principle is that during or shortly after shutdown, a high-power semiconductor chip may be mis-turned on due to abnormal drive signals or external circuit interference, causing a short circuit in the main circuit. This leads to the instantaneous melting and vaporization of the high-power semiconductor chip itself, its internal bonding wires, and the solder layer beneath the chip, generating a large amount of high-temperature, high-pressure explosive gas. This gas expands rapidly within the casing, generating enormous pressure, with instantaneous energy exceeding 10,000 J. When the pressure exceeds the ultimate mechanical strength of the ceramic substrate and casing, the casing ruptures, usually accompanied by a loud bang, smoke, and even visible flying metal or plastic fragments.

[0004] The existing power module housings have the following defects: traditional housings lack active pressure relief capabilities. When the internal pressure of the housing surges, there is nowhere to release it, which leads to brittle fracture or plastic deformation of the housing as a whole, and generates high-speed flying fragments, endangering the safety of surrounding equipment and personnel. Summary of the Invention

[0005] This invention provides a graded pressure relief explosion-proof pipe shell and power module. The purpose of the invention is to perform graded pressure relief of the gas when pressure gas is generated inside the pipe shell, thereby improving the active pressure relief capability and preventing the pipe shell from undergoing overall brittle fracture or plastic deformation under pressure.

[0006] On one hand, the present invention provides a graded pressure relief explosion-proof pipe shell, the graded pressure relief explosion-proof pipe shell comprising: A housing, suitable for covering the chip and connected to the substrate, wherein the housing is provided with a venting channel and an explosion venting channel respectively communicating with the inner cavity of the housing; further comprising: An explosive component, connected to the housing and used to seal the explosion relief channel; When the pressure inside the housing cavity is lower than the first pressure threshold, the venting channel can perform primary pressure relief on the housing cavity; when the pressure inside the housing cavity increases to the first pressure threshold, the connection between the rupture element and the housing fails and the venting channel opens to perform secondary pressure relief on the housing cavity.

[0007] The venting channels and rupture components on the shell can release high-pressure gas and energy in stages to meet the different pressure release requirements of the shell cavity, improve the active pressure relief capability of the shell, and prevent the shell from undergoing overall brittle fracture or plastic deformation under pressure.

[0008] In one embodiment, the housing includes a top wall disposed opposite to the substrate, and the venting channel and the rupture element are both disposed on the top wall. The rupture element is located on the side of the venting channel near the edge of the top wall of the shell.

[0009] In this embodiment of the invention, both the venting channel and the rupture element are disposed on the top wall of the shell; the rupture element is disposed on the side of the venting channel near the edge of the top wall. When pressurized gas is generated inside the shell, primary venting can be performed through the venting channel located on the top wall near the center to reduce the bulging of the middle of the top wall. When the gas pressure inside the shell cavity reaches a first pressure threshold, the rupture element near the edge of the top wall loses its connection with the shell, causing the venting channel near the edge of the top wall to open for secondary pressure relief, thus preventing breakage near the edge of the top wall and minimizing the deformation and breakage of the shell.

[0010] In one embodiment, the venting channel penetrates vertically through the top wall of the shell; a plurality of venting channels are evenly spaced along a first direction to form a channel array; Multiple sets of the channel arrays are evenly spaced along the second direction to form a channel matrix; The second direction is perpendicular to the first direction.

[0011] This design reduces the inner diameter of the venting channel, effectively preventing external dust from entering the casing. Furthermore, it forms a channel matrix to enhance the primary venting capacity of the casing.

[0012] As one implementation, reinforcing ribs are formed on the top wall of the shell at the positions of each group of channel arrays; Each of the reinforcing ribs extends along the distribution direction of the multiple discharge channels in each group of channel arrays, such that the multiple discharge channels are all located on the reinforcing rib.

[0013] The reinforcing ribs are used to increase the local thickness of the shell and, through their own high flexural modulus and structural stiffness, provide effective mechanical support for the stress concentration area around the venting channel, thereby improving the local rigidity of the shell, dispersing and resisting the explosion stress, and inhibiting the top wall of the shell from cracking or deforming at the venting channel.

[0014] In one embodiment, the housing further includes a circumferential sidewall connected to the circumferential edge of the top wall of the housing; A weak bursting section is provided on the peripheral sidewall. When the internal cavity of the shell is pressurized to a second pressure threshold that is greater than the first pressure threshold, the weak bursting section ruptures to provide three-stage pressure relief to the internal cavity of the shell.

[0015] When the internal pressure of the shell is below the first pressure threshold, the shell primarily relies on the venting channel for initial pressure relief. When the internal pressure of the shell increases to the first pressure threshold, the connection between the rupture element and the shell fails, opening the venting channel. The inner diameter of the venting channel is larger than that of the venting channel. At this point, the shell primarily relies on the venting channel for pressure relief, supplemented by the venting channel. This effectively prevents deformation near the center of the shell top wall and avoids fracture near the edge of the shell top wall. When the internal pressure of the shell continues to increase to the second pressure threshold, the weak rupture part ruptures, forming a rupture opening that further enhances the pressure relief capacity of the shell. This allows the shell to relieve pressure in stages. Simultaneously, by pre-setting weak points in the shell, the rupture location on the shell can be intervened in advance, preventing overall breakage or deformation of the shell.

[0016] In one embodiment, a stress groove is formed on the peripheral sidewall, and the stress groove does not penetrate the peripheral sidewall; The weak burst section is defined by the bottom plate of the stress groove.

[0017] By thinning the thickness of local areas of the peripheral wall, the thickness of the weak bursting part is made as the minimum thickness on the peripheral wall, forming a predetermined failure area with a strength lower than the overall strength of the shell. When the inner cavity of the shell continues to be pressurized to the second pressure threshold, it is ensured that the shell ruptures at the weak bursting part, while other parts of the shell do not break. This allows for early intervention at the rupture location of the shell, preventing the shell from breaking or deforming as a whole.

[0018] In one implementation, a plurality of the said weak explosive sections are arranged at intervals along a first direction to form a weak explosive array; Two sets of weak explosive arrays are respectively arranged on the two opposite side walls of the shell along the second direction.

[0019] On the other hand, embodiments of the present invention also provide a power module, which includes the graded pressure relief explosion-proof pipe shell as described in any one of claims 1-7, and further includes a substrate, a liner and a chip; The chip is mounted on a substrate and fixed to the substrate by the substrate; The housing covers the chip and is connected to the substrate.

[0020] The power module in this embodiment of the invention includes the graded pressure relief explosion-proof casing in the foregoing embodiments. Therefore, the power module in this embodiment can also achieve the beneficial effects that the graded pressure relief explosion-proof casing can achieve.

[0021] In one embodiment, the housing is provided with an insulating reinforcing rod extending along its length.

[0022] In one embodiment, the insulating reinforcing rod has screw holes, and the fastening screws pass through the screw holes on the insulating reinforcing rod and the housing in sequence, and are then threadedly connected to the threaded holes on the substrate. Attached Figure Description

[0023] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0024] Figure 1 This is an isometric view of the power module installation in an embodiment of the present invention; Figure 2 This is a front view of the power module in an embodiment of the present invention; Figure 3 This is a schematic diagram of the shell structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the insulating reinforcement rod in an embodiment of the present invention; Figure 5 This is a schematic diagram of the chip mounting structure on the substrate in an embodiment of the present invention; Figure 6 This is a schematic diagram showing the arrangement of six backing plates on a substrate; Figure 7 This is a schematic diagram showing the arrangement of five backing plates on a substrate; Figure 8 This is a schematic diagram showing the arrangement of four backing plates on a substrate.

[0025] Figure label: 100. Tube shell; 1. Shell; 11. Top wall of shell; 12. Peripheral side wall; 13. Clearance groove; 14. Mounting protrusion; 15. Mounting limit rail; 16. Anti-detachment stop; 17. Anti-detachment component; 2. Venting channel; 3. Explosion relief channel; 4. Explosive component; 5. Reinforcing rib; 6. Weak blasting section; 200, substrate; 201, mounting hole; 202, threaded hole; 300, backing plate; 400, chip; 401, IGBT chip; 402, FRD chip; 500, Insulation reinforcement rod; 501, Screw hole. Detailed Implementation

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] This invention provides a graded pressure relief explosion-proof pipe shell 100, which includes a shell 1 and a bursting element 4 disposed on the shell 1.

[0028] The housing 1 covers the power module. During installation, the power module can be mounted on the substrate 200, the housing 1 can be placed over the power module, and then the housing 1 can be sealed and fixedly connected to the substrate 200. The housing 1 provides physical protection for the power module. Optionally, the housing 1 is made of high-strength, melt-resistant, and deformation-resistant materials. Preferably, the housing 1 can be made of high-strength materials such as polyphthalamide (PPA) or polyphenylene sulfide (PPS), giving the housing 1 a high melting point, high heat distortion temperature, and excellent structural strength and rigidity, as well as high tensile strength, flexural modulus, and excellent dimensional stability. In addition, the housing 1 made of the above materials also has the characteristics of low density and light weight, which helps to achieve the weight reduction of the power module. The housing 1 is manufactured using a one-time injection molding process, which results in high integration of the housing 1, reduces the number of parts and assembly steps, and lowers costs. In practice, the shell 1 is made of PPA and PPS materials with added glass fiber or mineral filler. The filler filling rate is controlled within the range of 30%-50% to further enhance the mechanical strength and thermal stability of the shell 1.

[0029] In this embodiment of the invention, the housing 1 is provided with a venting channel 2 and a venting channel 3, which is normally open and used to connect the inner cavity of the housing 1 with the outside. When a small amount of pressurized gas is generated in the inner cavity of the housing 1, the pressurized gas can be discharged through the venting channel 3 to perform primary pressure relief on the inner cavity of the housing 1.

[0030] The shell 1 is also provided with an explosion relief channel 3. When the explosion relief channel 3 is opened, it can connect the inner cavity of the shell 1 with the outside. An explosive component 4 is provided to seal the explosion relief channel 3.

[0031] When the pressure inside the housing 1 is lower than the first pressure threshold, the venting channel 2 can perform primary pressure relief on the inside of the housing 1; when the pressure inside the housing 1 increases to the first pressure threshold, the explosive component 4 fails to connect with the housing 1 under the high pressure inside the housing 1, causing the explosion venting channel 3 to open, so as to perform secondary pressure relief on the inside of the housing 1.

[0032] With this configuration, the venting channel 2 and the rupture element 4 on the shell 1 can release the high-pressure gas and energy in the shell 1 in stages and in sequence to meet the different pressure release requirements of the inner cavity of the shell 1, improve the active pressure relief capability of the shell 100, and prevent the shell 1 of the shell 100 from undergoing overall brittle fracture or plastic deformation under pressure.

[0033] The rupture element 4 is made of the same material as the shell 1. The rupture element 4 is sheet-shaped and matches the inner diameter and shape of the explosion relief channel 3. The rupture element 4 can be bonded to the inner wall of the explosion relief channel 3 using adhesives such as epoxy resin, thus assembling the rupture element 4 with the shell 1. The first pressure threshold is equal to the bonding strength between the rupture element 4 and the shell 1. When the inner cavity of the shell 1 is pressurized to the first pressure threshold, the high-pressure explosion energy acts on the shell 1 and the rupture element 4, causing the bonding between them to fail. This allows the rupture element 4 to fly out of the explosion relief channel 3 and open it, guiding pressure release and thus providing secondary pressure relief to the inner cavity of the shell 1. This reduces the impact of the high-pressure gas on the entire shell 100, preventing further damage or fragmentation of the shell 100, thereby protecting external circuits and personnel safety.

[0034] Of course, the radial dimension of the explosive component 4 can also be set to be larger than the diameter of the outlet of the explosion relief channel 3, and the explosive component 4 can be bonded to the outlet of the explosion relief channel 3. Compared with the method of sealing the explosive component 4 on the inner wall of the explosion relief channel 3, the method of bonding the explosive component 4 to the outlet of the explosion relief channel 3 allows the explosive component 4 to fly out and smoothly open the explosion relief channel 3 after the adhesion to the shell 1 fails. The explosive component 4 does not need to move a preset distance within the explosion relief channel, so there is no problem of the explosive component 4 getting stuck in the explosion relief channel, thus ensuring that the explosion relief channel 3 opens smoothly.

[0035] Of course, the blasting component 4 can also be installed with the housing 1 by means of snap-fit ​​or other methods.

[0036] In this embodiment of the invention, the positions of the venting channel 2 and the rupture element 4 are arranged reasonably, as follows: The housing 1 includes a top wall 11 and a peripheral side wall 12 connected to the circumferential edge of the top wall 11, wherein the top wall 11 is disposed opposite to the substrate 200. A chip 400 is mounted on the substrate 200, and the housing 1 covers the chip 400 and is fixed to the substrate 200. When pressurized gas is generated inside the housing 1, the top wall 11 near the middle is prone to bulging and deformation outward, while stress concentration occurs near the edge of the top wall 11, making it prone to breakage.

[0037] To address the aforementioned technical problems, this embodiment of the invention provides both the venting channel 2 and the rupture element 4 on the top wall 11 of the shell. The rupture element 4 is positioned on the side of the venting channel 2 near the edge of the top wall 11. When pressurized gas is generated inside the shell 1, primary venting can be achieved through the venting channel 2 located on the top wall 11 near the center, thus reducing the bulging of the center of the top wall 11. When the gas pressure inside the shell 1 reaches a first pressure threshold, the rupture element 4 near the edge of the top wall 11 loses its connection with the shell 1, causing the venting channel 3 near the edge of the top wall 11 to open for secondary pressure relief, thereby preventing breakage near the edge of the top wall 11 and minimizing the deformation and breakage of the shell 1.

[0038] The arrangement of the discharge channel 2 will be explained below.

[0039] In this embodiment of the invention, the venting channel 2 penetrates the top wall 11 along a direction perpendicular to its thickness. Multiple venting channels 2 are evenly spaced along a first direction to form a channel array. Multiple channel arrays are evenly spaced along a second direction to form a channel matrix. The second direction is perpendicular to the first direction. Optionally, the first direction is the length direction of the shell 1, and the second direction is the width direction of the shell 1.

[0040] This configuration reduces the inner diameter of the discharge channel 2, effectively preventing external dust from entering the housing 1. Furthermore, it forms a channel matrix to enhance the primary discharge capacity of the housing 100.

[0041] Specifically, the channel matrix includes a first channel array, a second channel array, and a third channel array. The first channel array is located on the symmetrical center line of the top wall 11 of the shell. The second and third channel arrays are positioned on either side of the first channel array, directly opposite the chip 400 located within the shell 100 and directly above the chip 400. Multiple rupture pieces 4 are positioned on opposite sides of the channel matrix, with the rupture pieces positioned close to the edge of the top wall 11.

[0042] Since a channel matrix is ​​provided on the top wall 11, stress concentration occurs at the locations of each venting channel 2 on the top wall 11. In this embodiment of the invention, reinforcing ribs 5 are formed on the top wall 11 at the locations of each group of channel arrays. The reinforcing ribs 5 are used to increase the local thickness of the shell 1 and, through their own high bending modulus and structural stiffness, provide effective mechanical support for the stress concentration area around the venting channel 2 of the shell 100, improve the local rigidity of the shell 100, thereby dispersing and resisting the explosion stress and inhibiting the top wall 11 from cracking or deforming at the venting channel 2.

[0043] Each reinforcing rib 5 extends along the distribution direction of the multiple venting channels 2 within each group of channel arrays, ensuring that all multiple venting channels 2 are located on and pass through the reinforcing rib 5. In one embodiment, the reinforcing rib 5 and the top wall 11 are integrally injection molded, ensuring material consistency of the shell 1 and guaranteeing the structural integrity and stability of the shell 1.

[0044] The reinforcing rib 5 can be located on the inner or outer side of the top wall 11 of the shell, depending on actual requirements. The reinforcing rib 5 should be directly opposite the chip 400 inside the shell 100, and the reinforcing rib 5 should be located in the area directly above the chip 400. Based on the maximum expected explosion energy released by modules of different power levels under extreme short-circuit conditions, the optimal thickness of the reinforcing rib 5 is precisely optimized and determined through mechanical simulation and calculation.

[0045] The shell 100 in this embodiment of the invention has a three-stage pressure relief capability. Specifically, a weak bursting part 6 is also provided on the peripheral sidewall 12 of the shell 1. When the internal cavity of the shell 1 is pressurized to a second pressure threshold, the weak bursting part 6 ruptures to relieve pressure on the internal cavity of the shell 1. The second pressure threshold is greater than the first pressure threshold.

[0046] When the internal pressure of the shell 1 is lower than the first pressure threshold, the shell 100 mainly relies on the venting channel 2 for initial pressure relief. When the internal pressure of the shell 1 increases to the first pressure threshold, the connection between the rupture element 4 and the shell 1 fails, and the venting channel 3 opens. The inner diameter of the venting channel 3 is larger than the inner diameter of the venting channel 2. At this time, the shell 100 mainly relies on the venting channel 3 for pressure relief, and the venting channel 2 is used as a supplement. This can effectively prevent deformation near the middle of the shell top wall 11 and prevent fracture near the edge of the shell top wall 11. When the internal pressure of the shell 1 continues to increase to the second pressure threshold, the weak rupture part 6 ruptures, forming a rupture opening, which can further improve the pressure relief capacity of the shell 100, allowing the shell 1 to relieve pressure step by step. At the same time, the weak parts of the shell 1 are pre-defined, thereby intervening in the rupture location of the shell 1 in advance and preventing the shell 1 from breaking or deforming as a whole.

[0047] In this embodiment of the invention, a stress groove is formed on the peripheral sidewall 12. The stress groove does not penetrate the peripheral sidewall 12, and the weak bursting part 6 is defined by the bottom plate of the stress groove. That is, by thinning the thickness of a local location on the peripheral sidewall 12, the thickness of the weak bursting part 6 is made to be the minimum thickness on the peripheral sidewall 12, forming a predetermined failure area with a strength lower than the overall strength of the shell 100. When the inner cavity of the shell 1 continues to be pressurized to the second pressure threshold, it is ensured that the shell 1 ruptures at the weak bursting part 6, while other locations on the shell 1 do not break. This allows for early intervention at the rupture location on the shell 1, preventing the shell 1 from breaking or deforming as a whole.

[0048] The stress groove has a rectangular cross-section, which makes the cross-section of the weak explosive section 6 also rectangular. Of course, the cross-sections of the stress groove and the weak explosive section 6 can also be circular, triangular, or rhomboid.

[0049] Multiple weak explosive sections 6 are arranged at intervals along the first direction to form a set of weak explosive arrays; two sets of weak explosive arrays are respectively arranged on two opposite side walls of the shell 1 along the second direction.

[0050] In this embodiment of the invention, a clearance groove 13 is formed on the peripheral sidewall 12 of the housing 1. A mounting hole 202 is provided on the substrate 200 opposite to the clearance groove 13 on the housing 1. When the housing 1 is covered on the substrate 200, the clearance groove 13 provides mounting space, allowing the operator to insert bolts or screws into the mounting hole 202 on the substrate 200 from the clearance groove 13 and connect it with other external components, thereby fixing the substrate 200 to the external components.

[0051] Multiple clearance grooves 13 are respectively provided on opposite sides of the housing 1 in the width direction, and a circumferentially protruding mounting protrusion 14 is defined between two adjacent clearance grooves 13 on the housing 1. Each mounting protrusion 14 is the location on the housing 1 most prone to stress concentration, and therefore most susceptible to damage from explosion. In this embodiment of the invention, the rupture disc is disposed on the top wall of the mounting protrusion 14, and stress grooves are formed on the outer side wall of each mounting protrusion 14.

[0052] This invention also provides a power module, which includes the graded pressure relief explosion-proof pipe shell 100 in the aforementioned embodiments, as well as a substrate 200, a liner 300 and a chip 400. The chip 400 is mounted on the liner 300 and fixed to the substrate 200 by the liner 300. The shell 1 covers the power module and is sealed to the substrate 200.

[0053] The power module in this embodiment of the invention includes the graded pressure relief and explosion-proof housing 100 from the aforementioned embodiments. Therefore, the power module in this embodiment can also achieve the beneficial effects that the graded pressure relief and explosion-proof housing 100 can achieve. The power module in this embodiment of the invention can be applied to power electronic conversion units under high voltage and high current conditions, and can be used as a high-voltage rail transit power module to meet the stringent requirements of high power density, high reliability, and safety for systems such as rail transit vehicle traction converters. The substrate 200 mainly undertakes the functions of mounting, fixing, and heat dissipating the chip 400; the housing 100 covers the chip 400 and is fixed to the substrate 200, providing physical protection and pressure explosion-proof function for the internal chip 400.

[0054] The substrate 200 serves as the carrier for electrical systems such as the internal chip 400 of the power module. The substrate 200 is made of metallized ceramic material, which can be made of aluminum nitride or aluminum oxide material, and has excellent electrical insulation performance and high thermal conductivity.

[0055] The arrangement of the substrate 200 and the chips 400 on the substrate 200 is as follows: Several substrates 300 can be spaced apart along the width and length directions on the same substrate 200, and multiple chips 400 are disposed on each substrate 300. The number and power level of the power semiconductor chips 400 on the substrate 200 are configured according to the overall voltage and current ratings of the module.

[0056] For example, in a specific implementation case, a six-substrate 300 topology is proposed, which can also be designed as a four-substrate 300 or a five-substrate 300 layout. Each independent substrate 300 integrates four IGBT chips 401 and four FRD chips 402.

[0057] To meet the challenges of extreme applications involving higher voltages, larger currents, and faster switching frequencies, the interconnect layer between the power semiconductor chip 400 and the underlying substrate 300 is achieved using a silver sintering process. The silver sintering process is controlled at temperatures between 230℃ and 260℃ and pressures between 7 MPa and 8 MPa, allowing the organic matter in the nano-silver sintering paste to diffuse and volatilize, forming a dense silver layer with a high melting point and low porosity. Compared to traditional solder, this silver sintered layer exhibits higher connection strength, thermal conductivity, and creep resistance, enhancing the long-term reliability and stability of the interconnect interface and ensuring the module's service life under extreme operating conditions.

[0058] In this embodiment of the invention, an insulating reinforcing rod 500 extending along the length direction is provided on the top wall 11 of the housing 1. The insulating reinforcing rod 500 is detachably installed on the outer side of the top wall 11. When the chip 400 inside the housing 1 experiences a short circuit and explodes, the pressure inside the housing 1 rises sharply. As the main load-bearing component, the insulating reinforcing rod 500 can withstand huge instantaneous mechanical stress, thereby effectively resisting the deformation and warping of the housing 1, providing sufficient mechanical support for the power module as a whole, and preventing the fastening system from failing.

[0059] In one embodiment, a metal insert is embedded in the insulating reinforcing rod 500. A screw hole 501 is formed on the inner wall of the metal insert. The screw hole 501 is aligned with a threaded hole 201 on the substrate 200. During assembly, one end of a fastening screw passes through the external pressure strip or bracket, then sequentially passes through the screw hole 501 on the insulating reinforcing rod 500, the housing 1, and is threadedly connected to the threaded hole 201 on the substrate 200. This securely connects the external pressure strip or bracket, the insulating reinforcing rod 500, the housing 1, and the substrate 200. Simultaneously, it ensures reliable mechanical fixing and electrical contact between the housing 1 and the busbar terminals on the substrate 200, guaranteeing uniform pressure on the sealant layer between the housing 100 and the substrate 200, thus forming an effective seal.

[0060] The preload of the fastening screw can be adjusted by rotating it. The insulating reinforcing rod 500 is made of the same high-strength material as the base material of the housing 1, and the insulating reinforcing rod 500 is integrally formed by precision injection molding.

[0061] Of course, the metal insert can also be removed, and the screw hole 501 can be formed directly on the insulating reinforcing rod 500.

[0062] A mounting guide rail 15 extending along the length of the housing is formed on the top wall of the housing for accommodating the insulating reinforcing rod 500. An opening is formed at one end of the mounting guide rail 15 along its length, and an anti-detachment stop 16 is formed at the end of the mounting guide rail 15 away from the insertion opening. During installation, the insulating reinforcing rod 500 is inserted into the mounting guide rail 15, and its position within the mounting guide rail 15 is adjusted by pushing it at the opening. The anti-detachment stop 16 applies a force along the thickness direction of the insulating reinforcing rod 500, preventing it from detaching from the mounting guide rail 15.

[0063] Optionally, the mounting limit rail 15 is defined by the limit wall plates that are spaced apart from each other. The limit wall is provided with an anti-detachment component 17. The side of the anti-detachment component 17 facing the insulating reinforcing rod 500 is wedge-shaped. The anti-detachment component 17 is used to apply a clamping force along the width direction of the insulating reinforcing rod 500 to the insulating reinforcing rod 500, thereby causing the insulating reinforcing rod 500 to detach from the mounting limit rail 15.

[0064] The insulating reinforcing rods 500 are configured in two sets, and the two sets of insulating reinforcing rods 500 are symmetrically arranged on the top wall 11 of the shell about the center line of the substrate 200.

[0065] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A graded pressure relief explosion-proof pipe shell, characterized in that, include: A housing, suitable for covering the chip and connected to the substrate, wherein the housing is provided with a venting channel and an explosion venting channel respectively communicating with the inner cavity of the housing; Also includes: An explosive component, connected to the housing and used to seal the explosion relief channel; When the pressure inside the housing cavity is lower than the first pressure threshold, the venting channel can perform primary pressure relief on the housing cavity; when the pressure inside the housing cavity increases to the first pressure threshold, the connection between the explosive element and the housing fails and the venting channel opens to perform secondary pressure relief on the housing cavity. The housing includes a top wall disposed opposite to the base plate, and the venting channel and the rupture element are both disposed on the top wall; The rupture element is disposed on the side of the venting channel near the edge of the top wall of the shell; The housing also includes a circumferential sidewall connected to the circumferential edge of the top wall of the housing; A weak bursting section is provided on the peripheral sidewall. When the internal cavity of the shell is pressurized to a second pressure threshold that is greater than the first pressure threshold, the weak bursting section ruptures to relieve the internal cavity of the shell in three stages. An insulating reinforcing rod extending along the length direction is provided on the housing, and an installation limiting rail extending along the length direction of the housing is formed on the top wall of the housing for accommodating the insulating reinforcing rod. An opening is formed at one end of the installation limiting rail along the length, and an anti-detachment stop is formed at the end of the installation limiting rail away from the insertion opening.

2. The graded pressure relief explosion-proof pipe shell according to claim 1, characterized in that, The venting channel penetrates vertically through the top wall of the shell; multiple venting channels are evenly spaced along a first direction to form a channel array; Multiple sets of the channel arrays are evenly spaced along the second direction to form a channel matrix; The second direction is perpendicular to the first direction.

3. The graded pressure relief explosion-proof pipe shell according to claim 2, characterized in that, Reinforcing ribs are formed on the top wall of the shell at the locations of each group of channel arrays; Each of the reinforcing ribs extends along the distribution direction of the multiple discharge channels in each group of channel arrays, such that the multiple discharge channels are all located on the reinforcing rib.

4. The graded pressure relief explosion-proof pipe shell according to claim 1, characterized in that, The peripheral sidewall is provided with stress grooves, and the stress grooves do not penetrate the peripheral sidewall. The weak burst section is defined by the bottom plate of the stress groove.

5. The graded pressure relief explosion-proof pipe shell according to claim 4, characterized in that, Multiple weak explosive sections are arranged at intervals along a first direction to form a weak explosive array; Two sets of weak explosive arrays are respectively arranged on the two opposite side walls of the shell along the second direction.

6. A power module, characterized in that, The explosion-proof casing with graded pressure relief as described in any one of claims 1-5 further includes a substrate, a liner, and a chip; The chip is mounted on a substrate and fixed to the substrate by the substrate; The housing covers the chip and is connected to the substrate.

7. The power module according to claim 6, characterized in that, The insulating reinforcing rod has screw holes, and the fastening screws pass through the screw holes on the insulating reinforcing rod and the housing in sequence, and then are threadedly connected to the threaded holes on the substrate.

Images