Potting material and method for producing potting material

Abstract

An insulating potting material for protecting electronic components in a high voltage (HV) device, the insulating potting material comprising an elastomer, a cooling filler, and / or an electric field relaxation agent, the potting material characterized by a high efficiency dielectric strength.

Description

Technical Field

[0001] The present disclosure relates generally to high voltage (HV) specified electronic devices. More particularly, the present disclosure relates to insulating potting materials for HV electronic devices, and methods of producing the potting materials. Background Art

[0002] High voltage (HV) equipment, such as transformers, converters, modulators, controllers, and power supplies, is a critical component in a range of applications. One such application is electron microscopy (EM). In EM machines, the reliability of the HV power supply is crucial for producing high-resolution images. This power supply is required for the electrodes that operate the electron beam.

[0003] The demand for high-voltage (HV) machines that exhibit high resolution, controllability, reliability, and maintainability is growing. However, the reliability of devices that can withstand the high voltages and support this demand remains low. Existing HV devices occasionally experience discharges, which can lead to machine failure and / or damage to high-resolution images. Interestingly, one of the main reasons for this lack of performance is the potting material. In order to perform well in HV devices, potting materials should combine several key properties, such as high dielectric strength, high thermal conductivity, high adhesion, and low specific gravity.

[0004] Therefore, there is a need for a high performance potting material that will ensure all desired properties are combined in a single composition. Summary of the Invention

[0005] According to some embodiments, the present disclosure relates to a reliable potting material for HV equipment.

[0006] According to some embodiments, the potting material is configured to be characterized by high dielectric strength, high thermal conductivity, high adhesion, and low specific gravity. Thus, according to some embodiments, encapsulating HV devices using the high-performance potting materials disclosed herein enhances device performance, minimizes the incidence of partial discharge, and thus results in more reliable HV devices.

[0007] According to some embodiments, an optimized formulation of a potting material is provided herein, and the optimized formulation is designed to fully maintain the advantageous properties. Additionally, a method for producing a potting material and a potting component comprising the potting material formulation is provided.

[0008] According to some embodiments, provided herein is an insulating potting material for protecting electronic components in high voltage (HV) equipment, the potting material comprising: an elastomer at a concentration of 50% to 100% (w / w); a cooling filler at a concentration of 5% to 70% (w / w); and / or an electric field relaxant at a concentration of 0.005% to 0.2% (w / w), the potting material being characterized by an effective dielectric strength of at least about 80% of the theoretical dielectric strength of the potting material.

[0009] As used herein, the term "theoretical dielectric strength" is defined as a calculated weighted average when considering the dielectric strengths of the individual components of the potting material and their relative concentrations in the entire potting material, according to some embodiments.

[0010] As used herein, the term "effective dielectric strength" is defined as the actual measured dielectric strength, according to some embodiments. In a partial discharge (PD) detector device, this measurement is performed by gradually applying a voltage that matches the "theoretical dielectric strength" of the potting material. The ratio of the observed voltage (before any discharge event) to the expected voltage is proportional to the ratio between the effective dielectric strength and the theoretical dielectric strength.

[0011] According to some embodiments, partial discharge (PD) is less than about 10 mV at a frequency of less than about 10 events within 2 minutes of a 4 kV dc applied voltage.

[0012] According to some embodiments, the potting material is characterized by a thermal conductivity of at least about 0.2 W / m·K to 3 W / m·K.

[0013] According to some embodiments, the potting material exhibits a relative humidity of less than about 0.8 g / cm 3 Up to 2.0g / cm 3 proportion.

[0014] According to some embodiments, the elastomer includes phenolic polymers, epoxy resins, polyisoprene, butadiene polymers, styrene-butadiene copolymers, ethylene propylene rubber (specifically EPDM), butyl and halogenated butyl elastomers, polyurethanes, polysiloxanes, polychloroprene, nitrile rubber, polyacrylate rubber, fluorocarbon elastomers, or any combination thereof.

[0015] According to some embodiments, the elastomer is polydimethylsiloxane (PDMS).

[0016] According to some embodiments, the elastomer is characterized by a dielectric strength of about 400 V / mil to 600 V / mil.

[0017] According to some embodiments, the elastomer has a g / cm 3 Up to 2.0g / cm 3 proportion.

[0018] According to some embodiments, the elastomer is derived from at least two prepolymer parts, each of which has a physical state of a liquid and / or a semisolid gel.

[0019] According to some embodiments, at least one of the at least two prepolymer parts is characterized by a viscosity of about 300 cP to 4000 cP.

[0020] According to some embodiments, the at least two parts include a monomer, a cross-linker, a polymer, a prepolymer, a prepreg, a catalyst, a solvent, or any combination thereof.

[0021] According to some embodiments, the elastomer is characterized by a thermal conductivity of at least about 0.1 W / m·K.

[0022] According to some embodiments, the cooling filler includes BN, Al-N, Al-O, BO, Si-N, Si-O, Si-C, or any combination thereof.

[0023] According to some embodiments, the cooling filler includes BN and / or Al-N.

[0024] According to some embodiments, the cooling filler has a structural form of flakes, spheres, platelets, agglomerates, disks, powder, or any combination thereof.

[0025] According to some embodiments, the cooling filler is characterized by anisotropic thermal conductivity or isotropic thermal conductivity.

[0026] According to some embodiments, the isotropic thermal conductivity and / or the anisotropic in-plane thermal conductivity is at least about 170 W / m·K.

[0027] According to some embodiments, the electric field relaxant is selected from the group consisting of: carbon powder, carbon fibers, carbon nanotubes, stainless steel fibers, polymers, graphene nanotubes, graphite, graphene powder, metal powder, metal flakes, metal coated fibers, metal nanowires, coated derivatives thereof, doped derivatives thereof, and any combination thereof.

[0028] According to some embodiments, the metal includes silver, gold, copper, platinum, nickel, oxide derivatives thereof, carbonaceous derivatives thereof, or any combination thereof.

[0029] According to some embodiments, provided herein is an electronic assembly comprising a plurality of electronic components and a potting material as disclosed herein, wherein the assembly is configured to operate at a voltage of at least about 3 kV to 300 kV.

[0030] According to some embodiments, the component is a transformer, a power supply, a modulator, or an inverter.

[0031] According to some embodiments, the present invention provides a method for producing encapsulated electronic components, the method comprising: providing component A of an elastomer; adding an electric field relaxant and / or a cooling filler; mixing the elastomer with the electric field relaxant and / or the cooling filler to obtain a first mixture; blending component B of the elastomer into the first mixture to obtain a second mixture; and degassing the second mixture to obtain a encapsulating material in a prepolymerized form; providing a box including an electronic component; dispensing the prepolymerized encapsulating material into the box under vacuum; degassing the prepolymerized encapsulating material; and curing the prepolymerized encapsulating material in the electronic component; thereby obtaining an encapsulated electronic component.

[0032] Certain embodiments of the present disclosure may include some, all, or none of the advantages described above. One or more of the technical advantages will be readily apparent to those skilled in the art from the drawings, description, and claims included herein. Furthermore, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages.

[0033] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will now be described with respect to certain examples and embodiments with reference to the following illustrative drawings.

[0035] Figure 1 is an exemplary flow chart of a method for producing a potting material according to some embodiments.

[0036] Figure 2 is an exemplary flow chart of a method for producing potted electronic assemblies according to some embodiments. DETAILED DESCRIPTION

[0037] This detailed disclosure provides a potting material for high-voltage (HV) devices that addresses the unique challenges associated with HV devices. The material is designed to exhibit high dielectric strength, high thermal conductivity, high adhesion, and low specific gravity. These desirable properties are achieved through the use of a complementary combination of elastomers, electric field relaxants, and / or cooling fillers.

[0038] Elastomer materials have excellent adhesion and low glass transition temperature (T gThese properties help maintain the required insulation, which in turn reduces unwanted partial discharges. Additionally, by selecting the appropriate type of cooling filler in the appropriate amount, thermal conductivity can be adjusted. This feature is crucial for preventing overheating during high voltage operation while keeping the specific gravity low enough for easy handling. Finally, the addition of a small amount of an electric field relaxant allows for tuning of the resistance without compromising any of the desirable properties mentioned above.

[0039] Additionally, the present disclosure provides a method for producing a potted electronic component using the disclosed potting material.

[0040] According to some embodiments, provided herein is an insulating potting material for protecting electronic components in high voltage (HV) equipment, the potting material comprising: an elastomer at a concentration of about 50% to 100% (w / w), a cooling filler at a concentration of about 5% to 70% (w / w), and / or an electric field relaxant at a concentration of about 0.005% to 0.2% (w / w); advantageously, it has been found that the potting material is characterized by an effective dielectric strength of at least about 80% (e.g., at least about 85%, at least about 90%, at least about 95%, or preferably at least about 99%) of the theoretical dielectric strength of the potting material. Each possibility is a separate embodiment. According to some embodiments, the effective dielectric strength advantageously enables utilization of the potential theoretical dielectric strength of the potting material, thereby introducing sufficient insulation for the HV equipment.

[0041] According to some embodiments, the potting material is characterized by an effective dielectric strength of at least about 100% (e.g., at least about 110%, at least about 120%, at least about 130%, at least about 140%, at least about 150%, at least about 160%) of the theoretical dielectric strength of the potting material. Each possibility is a separate embodiment.

[0042] Surprisingly, and in accordance with some embodiments, the potting material has an effective dielectric strength of about 300 V / mil to 600 V / mil (e.g., about 350 V / mil to 400 V / mil, about 400 V / mil to 450 V / mil, about 450 V / mil to 500 V / mil, about 500 V / mil to 550 V / mil, or about 550 V / mil to 600 V / mil). Each possibility is a separate embodiment.

[0043] According to some embodiments, the potting material adheres well enough to the electronic components to minimize cracking and thus prevent partial discharge (PD). According to some embodiments, the potting material adheres well enough to the entire formulated potting material to minimize cracking and thus prevent PD.

[0044] Advantageously, and in accordance with some embodiments, PD is less than about 10 mV, e.g., less than about 8 mV, less than about 5 mV, less than about 3 mV, or preferably eliminated. According to some embodiments, PD occurs at a frequency of less than about 10 events (e.g., less than about 10 to 7 events, less than about 5 to 7 events, less than about 3 to 5 events, less than about 1 to 3 events) within 2 minutes of a 4 kV dc applied voltage, or preferably, no PD events occur at all within 2 minutes of a 4 kV dc applied voltage. Each possibility is a separate embodiment. According to some embodiments, PD occurs at a frequency of less than about 20 events (e.g., less than about 10 events, less than about 5 to 7 events, less than about 3 to 5 events, less than about 1 to 3 events) within 2 minutes of a 2 kV to 100 kV dc applied voltage, or preferably, no PD events occur at all within 2 minutes of a 2 kV to 100 kV dc applied voltage. Each possibility is a separate embodiment. According to some embodiments, PD occurs at a frequency of less than about 20 events (e.g., less than about 10 events, less than about 5 to 7 events, less than about 3 to 5 events, less than about 1 to 3 events) within 2 minutes of a 100 kV to 350 kV dc applied voltage, or preferably no PD events occur at all within 2 minutes of a 100 kV to 350 kV dc applied voltage. Each possibility is a separate embodiment. According to some embodiments, low PD (if any) improves the reliability of the potting material while allowing for maximum utilization of the theoretical dielectric strength of the potting material.

[0045] According to some embodiments, the concentration of the elastomer is about 90% (w / w), the concentration of the cooling filler is about 10% (w / w), and / or the concentration of the electric field relaxant is about 0.005% to 0.2% (w / w). According to some embodiments, the concentration of the elastomer is about 80% (w / w), the concentration of the cooling filler is about 20% (w / w), and / or the concentration of the electric field relaxant is about 0.005% to 0.2% (w / w). According to some embodiments, the concentration of the elastomer is about 70% (w / w), the concentration of the cooling filler is about 30% (w / w), and / or the concentration of the electric field relaxant is about 0.005% to 0.2% (w / w). According to some embodiments, the concentration of the elastomer is about 60% (w / w), the concentration of the cooling filler is about 40% (w / w), and / or the concentration of the electric field relaxant is about 0.005% to 0.2% (w / w). According to some embodiments, the concentration of the elastomer is about 50% (w / w), the concentration of the cooling filler is about 50% (w / w), and / or the concentration of the electric field relaxant is about 0.005% to 0.2% (w / w). Each possibility is a separate embodiment.

[0046] According to some embodiments, the potting material comprises approximately 50% to 95% (w / w) of a polyurethane-based elastomer, approximately 10% to 50% (w / w) of a BN cooling filler, and approximately 1% to 10% (w / w) of an Al-O cooling filler. According to some embodiments, the potting material comprises approximately 60% to 70% (w / w) of a polyurethane-based elastomer, approximately 30% to 40% (w / w) of a BN cooling filler, and / or approximately 30% to 40% (w / w) of an Al-O cooling filler. According to some embodiments, the potting material comprises approximately 70% to 80% of a polyurethane-based elastomer, approximately 20% to 30% (w / w) of a BN cooling filler, and / or approximately 20% to 30% (w / w) of an Al-O cooling filler. According to some embodiments, the potting material includes about 80% to 90% (w / w) polyurethane-based elastomer, about 10% to 20% (w / w) BN cooling filler, and / or about 10% to 20% (w / w) Al-O cooling filler. Each possibility is a separate embodiment.

[0047] According to some embodiments, the potting material comprises about 50% to 95% (w / w) of a silicone-based elastomer, about 10% to 50% (w / w) of a BN cooling filler, about 1% to 10% (w / w) of an Al-N cooling filler, and about 0.005% to 0.2% of a graphene nanotube concentrate. According to some embodiments, the potting material comprises about 60% to 70% (w / w) of a silicone-based elastomer, about 30% to 40% (w / w) of a BN cooling filler and / or about 30% to 40% (w / w) of an Al-N cooling filler, and about 0.005% to 0.2% (w / w) of a graphene nanotube concentrate. According to some embodiments, the potting material comprises about 70% to 80% (w / w) silicone-based elastomer, about 20% to 30% (w / w) BN cooling filler and / or about 20% to 30% (w / w) Al-N cooling filler, and about 0.005% to 0.2% (w / w) graphene nanotube concentrate. According to some embodiments, the potting material comprises about 80% to 90% (w / w) silicone-based elastomer, about 10% to 20% (w / w) BN cooling filler and / or about 10% to 20% (w / w) Al-N cooling filler, and about 0.005% to 0.2% (w / w) graphene nanotube concentrate. Each possibility is a separate embodiment.

[0048] According to some embodiments, the potting material includes about 50% to 95% (w / w) epoxy-based elastomer, about 10% to 50% (w / w) BN cooling filler, about 1% to 10% (w / w) Si-N cooling filler, and about 0.005% to 0.2% (w / w) graphite concentrate. According to some embodiments, the potting material includes about 60% to 70% (w / w) epoxy-based elastomer, about 30% to 40% (w / w) BN cooling filler and / or about 30% to 40% (w / w) Si-N cooling filler, and about 0.005% to 0.2% (w / w) graphite concentrate. According to some embodiments, the potting material includes about 70% to 80% (w / w) epoxy-based elastomer, about 20% to 30% (w / w) BN cooling filler and / or about 20% to 30% (w / w) Si-N cooling filler, and about 0.005% to 0.2% (w / w) graphite concentrate. According to some embodiments, the potting material includes about 80% to 90% (w / w) epoxy-based elastomer, about 10% to 20% (w / w) BN cooling filler and / or about 10% to 20% (w / w) Si-N cooling filler, and about 0.005% to 0.2% (w / w) graphite concentrate. Each possibility is a separate embodiment.

[0049] According to some embodiments, the potting material includes about 50% to 99.9% (w / w) epoxy-based elastomer and about 0.005% to 0.2% (w / w) graphite or graphene nanotube concentrate.

[0050] According to some embodiments, the potting material includes about 50% to 99.9% (w / w) silicone-based elastomer and about 0.005% to 0.2% (w / w) graphite or graphene nanotube concentrate.

[0051] According to some embodiments, the potting material comprises about 50% to 100% (w / w) silicone-based elastomer.

[0052] According to some embodiments, the potting material includes about 50% to 100% (w / w) polydimethylsiloxane.

[0053] According to some embodiments, the potting material comprises about 50% to 100% (w / w) polyurethane.

[0054] According to some embodiments, the potting material includes about 50% to 100% (w / w) epoxy polymer.

[0055] According to some embodiments, the potting material is characterized by a thermal conductivity of at least about 0.2 W / m·K to 3 W / m·K (e.g., at least about 0.2 W / m·K to 1 W / m·K, at least about 1 W / m·K to 2 W / m·K, or at least about 2 W / m·K to 3 W / m·K). Each possibility is a separate embodiment. Advantageously, according to some embodiments, the high conductivity protects the electronic components from overheating.

[0056] According to some embodiments, the potting material exhibits a relative humidity of approximately 0.8 g / cm 3 Up to 2.0g / cm 3 (For example, about 0.8 g / cm 3 Up to 1g / cm 3 , about 1g / cm 3 to 1.2g / cm 3 , about 1.2g / cm 3 Up to 1.5g / cm 3 or about 1.5g / cm 3 Up to 2.0g / cm 3 Each possibility is a separate embodiment. According to some embodiments, a lightweight potting material advantageously facilitates handling of the potting material and potting components.

[0057] According to some embodiments, the potting material is characterized by a glass transition temperature (Tg) of about (-170)°C to (+170)°C (e.g., about (-170)°C to (-120)°C, about (-120)°C to (-80)°C, about (-80)°C to (-20)°C, about (-20)°C to (+50)°C, about (+50)°C to (+120)°C, or about (+120)°C to (+170)°C). g Each possibility is a separate embodiment. According to some embodiments, this characteristic glass transition temperature prevents brittleness, adheres better, and reduces the hardness of the potting material over the operating temperature range.

[0058] According to some embodiments, the potting material has a hardness of less than about 80 according to Shore 00 and less than about 50 according to Shore A. According to some embodiments, the relatively low T g and low hardness thereby allowing HV operation with minimal adhesive failure, minimal electrical discharge, and minimal mechanical vibration.

[0059] According to some embodiments, the elastomer is selected from, but not limited to, phenolic polymers, epoxy resins, polyisoprene, butadiene polymers, styrene-butadiene copolymers, ethylene propylene rubber (particularly EPDM), butyl and halobutyl elastomers, polyurethanes, polysiloxanes, polychloroprene, nitrile rubber, polyacrylate rubber, fluorocarbon elastomers, or any combination thereof. Each possibility is a separate embodiment.

[0060] According to some embodiments, the elastomer is polydimethylsiloxane (PDSM).

[0061] According to some embodiments, the elastomer is characterized by a dielectric strength of about 400 V / mil to 600 V / mil (e.g., about 400 V / mil to 450 V / mil, about 450 V / mil to 500 V / mil, about 500 V / mil to 550 V / mil, or about 550 V / mil to 600 V / mil). Each possibility is a separate embodiment.

[0062] According to some embodiments, the specific gravity of the elastomer is 0.8 g / cm 3 Up to 2.0g / cm 3 , for example, 0.8 g / cm 3 to 1.2g / cm 3 , about 1.2g / cm 3 Up to 1.6g / cm 3 or about 1.6g / cm 3 Up to 2.0g / cm 3 Each possibility is a separate embodiment.

[0063] According to some embodiments, the elastomer is polymerized from one or two prepolymer parts. According to some embodiments, the parts are in the physical state of a liquid, a solid and / or a semi-solid gel.

[0064] According to some embodiments, at least one of the one or both parts of the prepolymer is characterized by a viscosity of about 300 cP to 3000 cP (e.g., about 300 cP to 500 cP, about 900 cP to 1300 cP, about 1300 cP to 1700 cP, about 1700 cP to 2000 cP, about 2000 cP to 3000 cP, or preferably about 500 cP to 900 cP). Each possibility is a separate embodiment. According to some embodiments, the low viscosity prevents bubble formation. According to some embodiments, the low viscosity facilitates handling during production of the potted component and prevents PD events during HV operation.

[0065] According to some embodiments, one or both parts of the prepolymer are selected from, but not limited to, monomers, crosslinkers, polymers, prepolymers, prepregs, catalysts, solvents, or any combination thereof. Each possibility is a separate embodiment.

[0066] According to some embodiments, the elastomer is characterized by a thermal conductivity of at least about 0.1 W / m·K (e.g., at least about 0.5 W / m·K to 1.0 W / m·K, at least about 1.0 W / m·K to 1.5 W / m·K, at least about 1.5-2 W / m·K, or preferably about 0.1 W / m·K to 0.5 W / m·K). Each possibility is a separate embodiment.

[0067] According to some embodiments, the cooling filler includes, but is not limited to, BN, Al-N, Al-O, BO, Si-N, Si-O, Si-C, or any combination thereof. Each possibility is a separate embodiment. According to some embodiments, the cooling filler preferably includes BN and / or Al-N.

[0068] According to some embodiments, the cooling filler has a structural form selected from, but not limited to, flakes, spheres, platelets, agglomerates, disks, powders, or any combination thereof. Each possibility is a separate embodiment.

[0069] According to some embodiments, the cooling filler is characterized by anisotropic thermal conductivity or isotropic thermal conductivity.

[0070] According to some embodiments, the in-plane conductivity of the anisotropic thermal conductivity is approximately an order of magnitude higher than the through-plane thermal conductivity of the anisotropic conductivity. According to some embodiments, the high in-plane thermal conductivity increases the effectiveness of the cooling filler per a given amount of cooling filler. According to some embodiments, the high effectiveness of the in-plane anisotropic cooling filler requires a smaller amount of cooling filler to be added to the potting material compared to an isotropic cooling filler. According to some embodiments, reducing the amount of cooling filler reduces the specific gravity of the potting material.

[0071] According to some embodiments, the isotropic thermal conductivity and / or the anisotropic in-plane thermal conductivity is at least about 170 W / m·K, for example, at least about 170 W / m·K to 250 W / m·K, at least about 250 W / m·K to 350 W / m·K, at least about 350 W / m·K to 450 W / m·K, at least about 450 W / m·K to 550 W / m·K, at least about 550 W / m·K to 650 W / m·K, or at least about 650 W / m·K to 750 W / m·K. Each possibility is a separate embodiment.

[0072] According to some embodiments, the cooling filler is characterized by about 0.2 g / cm 3 to 1.1 g / cm 3 (For example, about 0.2 g / cm 3 to 0.4g / cm 3 , about 0.4g / cm 3 to 0.6g / cm 3 , about 0.6g / cm 3 to 0.8g / cm 3 or about 0.8g / cm 3 to 1.1 g / cm 3 Each possibility is a separate embodiment.

[0073] According to some embodiments, the cooling filler is characterized by a dielectric strength of about 300 V / mil to 1800 V / mil (e.g., about 300 V / mil to 500 V / mil, about 500 V / mil to 700 V / mil, about 700 V / mil to 900 V / mil, about 900 V / mil to 1100 V / mil, about 1100 V / mil to 1300 V / mil, about 1300 V / mil to 1500 V / mil, or about 1500 V / mil to 1800 V / mil).

[0074] According to some embodiments, the electric field relaxant is selected from, but not limited to, carbon powder, carbon fiber, carbon nanotube, stainless steel fiber, polymer, graphene nanotube, graphite, graphene powder, metal powder, metal flake, metal coated fiber, metal nanowire, coated derivatives of the above, doped derivatives, and any combination thereof. Each possibility is a separate embodiment. According to some embodiments, the metal of the electric field relaxant is selected from, but not limited to, silver, gold, copper, platinum, nickel, oxide derivatives of the above, carbonaceous materials of the above, or any combination thereof.

[0075] According to some embodiments, the electric field relaxant is a graphene nanotube.

[0076] According to some embodiments, low concentrations of electric field relaxants enable the resistivity of the potting material to be reduced and fine-tuned while maintaining minimal impact on the properties of the potting material.

[0077] According to some embodiments, the electric field relaxant can increase the volume resistivity of the potting material from about 10 15 Ω·cm is reduced to 10 1 Ω·cm, preferably from about 10 15 Ω·cm is reduced to 10 07 Ω·cm. For example, the volume resistivity can be reduced to about 10 15 Ω·cm to 10 13 Ω·cm, about 10 13 Ω·cm to 10 11 Ω·cm, about 10 11 Ω·cm to 10 09 Ω·cm, about 10 11 Ω·cm to 10 09 Ω·cm or about 10 09 Ω·cm to 10 07 Ω·cm. Each possibility is a separate embodiment. According to some embodiments, the electric field relaxer reduces leakage current, thereby preventing partial discharge and allowing high voltage operation with minimal failure.

[0078] According to some embodiments, an assembly of electronic components including the potting material disclosed herein is provided, the assembly being configured to operate at medium and high voltages. According to some embodiments, the assembly is configured to operate at a voltage of about 2 kV to 350 kV, for example, the assembly is configured to operate at a voltage of about 2 kV to 10 kV, about 10 kV to 30 kV, about 30 kV to 50 kV, about 50 kV to 100 kV, about 100 kV to 200 kV, or about 200 kV to 350 kV. Each possibility is a separate embodiment.

[0079] According to some embodiments, the assembly of electronic components is capable of operating at high voltage for a period of at least about 5 hours, at least about 10 hours, at least about one day, at least about one month, or at least about one year. Each possibility is a separate embodiment. According to some embodiments, the assembly of electronic components is capable of operating at high voltage for a period of at least about 5 hours to about one hour, at least about 5 hours to about 10 hours, at least about one day, at least about one month, or at least about one month to about one year. Each possibility is a separate embodiment.

[0080] According to some embodiments, the component is selected from, but not limited to, a transformer, a power supply, a modulator, and an inverter. Each possibility is a separate embodiment.

[0081] According to some embodiments, a method for producing a potting material is provided, the method comprising: providing an elastomer component A; adding an electric field relaxant and / or a cooling filler; mixing the elastomer with the electric field relaxant and / or the cooling filler to obtain a first mixture; blending the elastomer component B into the first mixture to obtain a second mixture; and degassing the second mixture to obtain a potting material in a prepolymerized form. According to some embodiments, a degassing step is further added to the obtained first mixture.

[0082] Now refer to Figure 1 , Figure 1 A flow chart 200 illustrating a method for producing a potting material is schematically illustrated. In step 202, component A of an elastomer is provided. In step 204, an electric field relaxant and / or a cooling filler are added. In step 206, the elastomer, electric field relaxant, and / or cooling filler are mixed to obtain a first mixture. In step 208, component B of the elastomer is blended into the first mixture to obtain a second mixture. In step 210, the second mixture is degassed to obtain a potting material in a prepolymerized form.

[0083] According to some embodiments, mixing the elastomer with the electric field relaxation agent and / or the cooling filler to obtain a first mixture comprises stirring at a rate of about 300 rpm to 3000 rpm (e.g., about 300 rpm to 800 rpm, about 800 rpm to 1500 rpm, about 1500 rpm to 2600 rpm, or about 2600 rpm to 3000 rpm). Each possibility is a separate embodiment.

[0084] According to some embodiments, blending the elastomer component B into the first mixture to obtain the second mixture comprises stirring at a rate of about 100 rpm to 2000 rpm (e.g., about 100 rpm to 800 rpm, about 800 rpm to 1400 rpm, or about 1400 rpm to 2000 rpm). Each possibility is a separate embodiment.

[0085] According to some embodiments, a method for producing a potted electronic component is provided herein, the method comprising: providing a box comprising an electronic component; dispensing the prepolymerized potting material disclosed herein into the box under vacuum; degassing the potting material; and curing the potting material within the electronic component; thereby obtaining the potted electronic component.

[0086] Now refer to Figure 2 , Figure 2 A flowchart 400 illustrating a method for producing a potted electronic assembly is schematically illustrated. In step 402, a box containing an electronic assembly is provided. In step 404, a prepolymerized potting material is dispensed into the box under vacuum. In step 406, the potting material is degassed. In step 408, the potting material within the electronic assembly is cured, thereby obtaining a potted electronic assembly.

[0087] According to some embodiments, the curing time is less than about 72 hours, for example, less than about 72 hours to 48 hours, less than about 48 hours to 32 hours, less than about 32 hours to 24 hours, or preferably less than about 24 hours.

[0088] According to some embodiments, provided herein is an assembly of electronic components including the potting material disclosed herein.

[0089] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. For the sake of clarity, the following definitions are provided.

[0090] Unless specifically stated otherwise, the terms "a" or "an" as used herein include both the singular and the plural. Therefore, in this application, the terms "a", "an" or "at least one" can be used interchangeably.

[0091] As used herein, the verb "to comprise" and its conjugations as used in the specification and claims is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluding.

[0092] As used herein, the term "about" when used in conjunction with a numerical value includes ±10% of the indicated value. In addition, all ranges for the same component or property herein include endpoints, are independently combinable, and include all intermediate points and intermediate ranges. It should be understood that where a parameter range is provided, the present invention also provides all integers and tenths thereof within that range.

[0093] As used herein, the term "potting material" refers to a material used to fill a complete electronic component with a solid or gel compound, according to some embodiments. The main application is for high-voltage components by excluding gas phenomena (such as corona discharge, insulation, shock and vibration resistance), and excluding water, moisture or corrosive agents.

[0094] As used herein, according to some embodiments, the term "elastomer" refers to a material characterized by deformation of the material with substantially complete recoverability. For a material to exhibit this type of elasticity, three molecular requirements must be met: (1) the material comprises polymer chains, (2) the chains are highly flexible and mobile, and (3) the chains are linked into a network structure.

[0095] As used herein, the term "cooling filler" refers to a component that increases the thermal conductivity of a potting material, according to some embodiments.

[0096] As used herein, according to some embodiments, the term "field relaxer" refers to a conductive component capable of adjusting the volume resistivity of a potting material. According to some embodiments, the concentration of the field relaxer (expressed as w / w) refers to the relative weight of a concentrate of the field relaxer, the concentrate comprising the field relaxer and a carrier.

[0097] As used herein, according to some embodiments, the term "volume resistivity" is the ratio of the DC voltage per unit thickness to the amount of current per unit area passing through the material. Volume resistivity is typically expressed in units of [Ω·cm].

[0098] As used herein, the term "high voltage" refers to a voltage of about 100 kV to 350 kV.

[0099] As used herein, the term "medium voltage" refers to voltages of approximately 2 kV to 100 kV.

[0100] As used herein, according to some embodiments, the term "prepolymer portion" refers to a component used to produce a polymer.

[0101] As used herein, according to some embodiments, the term "pre-polymeric form" refers to a form of the potting material mixture that includes a polymer portion prior to polymerization.

[0102] In the description provided herein, various aspects of the present disclosure are described. For purposes of explanation, specific configurations and details are set forth to provide a thorough understanding of the different aspects of the present disclosure. However, it will also be clear to those skilled in the art that the present disclosure can be practiced without the specific details presented herein. In addition, well-known features may be omitted or simplified to avoid obscuring the present disclosure.

[0103] The following examples are provided to more thoroughly illustrate some embodiments of the present invention. However, they should not be construed as limiting the broad scope of the present invention. Those skilled in the art can easily devise many variations and modifications of the principles disclosed herein without departing from the scope of the present invention.

[0104] Example

[0105] Example 1 – Production of potting material

[0106] A mixing container with an 11 cm diameter and a total volume of 1.5 L was positioned inside a larger cooling container filled with water at approximately 10°C. 199 grams of Part A of the silicone elastomer were slowly added to the mixing container. 2 grams of the graphene nanotube concentrate were then added to the mixing container, followed by stirring at 1600 rpm for 15 minutes. The impeller was positioned at halfway the liquid level. The mixture was then degassed until no bubbles were observed. After inspecting the mixture with a microscope to ensure its transparency, 199 grams of Part B of the silicone elastomer were added. The mixture was further stirred at 1600 rpm for 10 minutes. From this point on, all additional steps should be performed within 30 to 60 minutes before the curing step begins. The mixture was then transferred to a vacuum chamber and subsequently evacuated to a pressure of approximately 1 Torr for 2 minutes, followed by re-venting to atmospheric pressure. The evacuation and ventilation steps were repeated twice to remove all bubbles from the container and piping.

[0107] Example 2 – Production of potting material

[0108] A mixing container with an 11 cm diameter and a total volume of 1.5 L is positioned inside a larger cooling container filled with water at approximately 10°C. 100 grams of Part A of the silicone elastomer is slowly added to the mixing container. 40 grams of the cooling filler is then added to the mixing container, followed by stirring at 200 rpm for 5 minutes. The impeller is positioned at half the liquid level. The mixture is then degassed until no bubbles are observed. After inspecting the mixture with a microscope to ensure its transparency, 100 grams of Part B of the silicone elastomer is added. The mixture is further stirred at 200 rpm for 5 minutes. From this point on, all additional steps should be performed within 30 to 60 minutes before the curing step begins. The mixture is then transferred to a vacuum chamber and subsequently evacuated to a pressure of approximately 1 torr for 2 minutes, followed by re-venting to atmospheric pressure. The evacuation and ventilation steps are repeated twice to remove all bubbles from the container and piping.

[0109] Example 3 – Production of potted electronic components

[0110] Position the box with the connected electronic components in a vacuum chamber. Tilt the box, equipped with a funnel, 10 degrees, positioning the dispensing inlet to lift upward, and evacuate the vacuum chamber to a reduced pressure of 1 Torr. Then dispense a mixture of prepolymer potting material through the inlet. Evacuate the chamber to 1 Torr for 2 minutes until all bubbles are removed, followed by venting for 2 minutes. Perform two additional evacuation and venting cycles, and finally, allow the potted box to cure under ventilation for approximately 24 hours, until the potting material is completely dry.

[0111] Example 4 - Testing for partial discharge

[0112] Partial discharge evaluation of the potting material, including parts A and B, was performed using an HVNS module in an SHVM BP5 cage. A 4 kV DC voltage was applied for 2 minutes, and measurements were taken using a PD detector. As shown in Table 1, three of the four measurement cycles produced PD events, while one measurement did not. The maximum peak was observed at a voltage of approximately 2.3 mV to 2.8 mV.

[0113] Table 1

[0114] test# 1 2 3 4 PD Events 2 0 2 3 Maximum peak, mV 2.3 0 2.8 2.7

[0115] Example 5 - Testing for partial discharge

[0116] A configuration was constructed with a distance of 1 mm between the electrodes and potted with a potting material having a theoretical dielectric strength of 470 V / mil. In theory, this dielectric strength should maintain a voltage of 19 kV without experiencing a PD event. In this example, a voltage of 30 kV was applied to the electrodes and the PD detector was connected for more than 2 hours. Advantageously, no PD events or dielectric failures were detected during the test, indicating that the effective dielectric strength reached 750 V / mil, which is 160% higher than the expected theoretical dielectric strength value. Therefore, in this case, the dielectric strength was thoroughly utilized and even exceeded 100% under the current experimental conditions (i.e., time, voltage, etc.).

[0117] The description of various embodiments of the present invention has been presented for the purpose of illustration and is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, practical applications, or technical improvements over technologies emerging in the marketplace, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0118] Although certain embodiments of the present invention have been illustrated and described, it will be clear that the present invention is not limited to the embodiments described herein. Many modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the present invention as described in the appended claims.

Claims

1. An insulating potting material for protecting electronic components in high voltage (HV) equipment, the potting material comprising: - an elastomer in a concentration of 50% to 100% (w / w); - a cooling filler in a concentration of 5% to 70% (w / w); and / or - an electric field relaxant at a concentration of 0.005% to 0.2% (w / w), Wherein the potting material is characterized by an effective dielectric strength of at least about 80% of a theoretical dielectric strength of the potting material.

2. The potting material of claim 1, wherein the partial discharge (PD) is less than about 10 mV at a frequency of less than about 10 events within 2 minutes of a 4 kV dc applied voltage.

3. The potting material of claim 1, wherein the potting material is characterized by a thermal conductivity of at least about 0.2 W / m·K to 3 W / m·K.

4. The potting material of claim 1 , wherein the potting material exhibits a relative humidity of less than about 0.8 g / cm 3 Up to 2.0g / cm 3 proportion.

5. The potting material of claim 1 , wherein the elastomer comprises a phenolic polymer, an epoxy resin, polyisoprene, a butadiene polymer, a styrene-butadiene copolymer, an ethylene propylene rubber (particularly EPDM), a butyl and halogenated butyl elastomer, a polyurethane, a polysiloxane, a polychloroprene, a nitrile rubber, a polyacrylate rubber, a fluorocarbon elastomer, or any combination thereof. The potting material of claim 5 , wherein the elastomer is polydimethylsiloxane (PDMS).

7. The potting material of claim 1, wherein the elastomer is characterized by a dielectric strength of approximately 400 V / mil to 600 V / mil.

8. The potting material of claim 1, wherein the elastomer is derived from at least two prepolymer parts, each of the at least two prepolymer parts having a physical state of a liquid and / or a semisolid gel.

9. The potting material of claim 8, wherein at least one of the at least two prepolymer parts is characterized by a viscosity of about 300 cP to 4000 cP.

10. The potting material of claim 8, wherein the at least two parts comprise a monomer, a cross-linking agent, a polymer, a prepolymer, a prepreg, a catalyst, a solvent, or any combination thereof.

11. The potting material of claim 1 , wherein the elastomer is characterized by a thermal conductivity of at least about 0.1 W / m·K. 12 . The potting material according to claim 1 , wherein the cooling filler comprises BN, Al—N, Al—O, BO, Si—N, Si—O, Si—C, or any combination thereof. 13 . The potting material according to claim 1 , wherein the cooling filler comprises BN and / or Al—N.

14. The potting material of claim 1, wherein the cooling filler has a structural form of flakes, spheres, platelets, agglomerates, disks, powders, or any combination thereof.

15. The potting material of claim 1, wherein the cooling filler is characterized by anisotropic thermal conductivity or isotropic thermal conductivity, and wherein the isotropic thermal conductivity and / or the anisotropic in-plane thermal conductivity is at least about 170 W / m·K.

16. The potting material of claim 1, wherein the electric field relaxant is selected from the group consisting of carbon powder, carbon fibers, carbon nanotubes, stainless steel fibers, polymers, graphene nanotubes, graphite, graphene powder, metal powder, metal flakes, metal-coated fibers, metal nanowires, coated derivatives thereof, doped derivatives thereof, and any combination thereof. 17 . The potting material of claim 16 , wherein the metal comprises silver, gold, copper, platinum, nickel, oxide derivatives thereof, carbonaceous materials thereof, or any combination thereof.

18. An electronic assembly comprising a plurality of electronic components and the potting material of claim 1, wherein the assembly is configured to operate at a voltage of at least about 3 kV to 300 kV.

19. The component of claim 18, wherein the component is a transformer, a power supply, a modulator, or an inverter.

20. A method for producing a potted electronic component, the method comprising: Providing component A of the elastomer; Adding electric field relaxants and / or cooling fillers; mixing the elastomer with the electric field relaxant and / or the cooling filler to obtain a first mixture; blending the elastomer component B into the first mixture to obtain a second mixture; as well as degassing the second mixture to obtain the potting material in a prepolymerized form; providing a box including the electronic assembly; dispensing the prepolymeric potting material into the box under vacuum; degassing the prepolymeric potting material; as well as curing the prepolymerized potting material within the electronic component; The potted electronic component is thus obtained.

Images