Daim duab 1.Thermal koob yees duab duab ntawm tuab -section potted power modules nquag nthuav tawm cov txheej potting raws li qhov tseem ceeb ntawm thermal resistance - ib qho txawv txav tsis tuaj ntawm feem ntau thawj thermal qauv.
Cov qauv thermal pom qhov sib txuas ntawm qhov kub ntawm 95℃nyob rau hauv tag nrho cov load. Lub rooj sib txoos khiav ntawm 118 degree. Cov khoom xa rov qab pib ntawm 14 lub hlis - IGBT rooj vag qhov chaw pib drift, electrolytic capacitor tsis ua hauj lwm, solder joint fatigue concentrated nyob ib ncig ntawm qhov siab -dissipation tsam. Pab pawg engineering tshawb xyuas cov khoom zoo. PCB tooj liab hnyav. Lub heatsink tiv taus. Tsis muaj leej twg qhib cov qauv thermal thiab ntxiv cov kab khoom rau epoxy potting compound ntawm cov khoom thiab cov phab ntsa. Cov kab ntawv ntawd, yog nws tau suav nrog, yuav tau pom tias muaj kev tiv thaiv thermal ntawm 0.04-0.06 K / W ib cm² ntawm tus qauv potting thickness - txaus los suav rau feem ntau ntawm qhov tsis sib xws ntawm cov qauv thiab kev ntsuas.
Standard epoxy potting compounds ntawm 0.5 W/m·K tsis thermally nruab nrab hauv tuab -section designs. Lawv yog cov thermal insulators nrog cov nplaim taws - ua haujlwm retardant. Kev kho lawv raws li thermally pob tshab nyob rau hauv lub hwj chim electronics thermal qauv yog qhov ua rau, tsis yog cov tsos mob, ntawm qhov teeb meem kub junction.
Thermal Resistance of a Potting Layer: Kev ntsuam xyuas ntau
Thermal resistance los ntawm ib txheej txheej txheej yog xam raws li R=t / (k × A), qhov twg t yog txheej thickness, k yog thermal conductivity, thiab A yog cross-sectional cheeb tsam. Rau cov txheej txheem potting compound ntawm k=0.5 W/m·K:
Ntawm 10 mm thickness, 1 cm² cheeb tsam: R=0.010 / (0.5 × 0.0001)=0.20 K/W
Ntawm 15 mm thickness, 1 cm² cheeb tsam: R=0.015 / (0.5 × 0.0001)=0.30 K/W
Ntawm 20 mm thickness, 1 cm² cheeb tsam: R=0.020 / (0.5 × 0.0001)=0.40 K/W
Cov no tsis yog negligible nqi. Lub hwj chim module dissipating 5 W mus txog 15 mm × 1 cm² potting seem ntsib qhov kub nce ntawm 1.5℃nyob rau hauv potting ntawm 0.5 W / m·K - uas suab me me kom txog rau thaum tus ntoo khaub lig-sectional cheeb tsam yog 2 cm², lub dissipation yog 20 W, thiab qhov kub qhov chaw yog concentrated. Nyob rau hauv ntom fais fab modules layouts qhov twg ntau dissipating Cheebtsam sib koom ib potted ntim, cumulative thermal resistance ntawm potting txheej pab txhawb 15–30℃rau hlws ris{13}}rau- ambient pob nyiaj siv nyob rau hauv cov qauv uas qhov kev koom tes no tsis yog qauv.
Ntawm k=1.5 W/m·K, tib lub geometry ua rau ib qho -peb lub thermal kuj. Txawm hais tias qhov kev txo qis no muaj txiaj ntsig yog nyob ntawm seb lwm qhov kev tawm tsam hauv txoj kev thermal yog - yog tias qhov kev sib tshuam - mus rau - rooj plaub ntawm cov tivthaiv dominates, kev txhim kho cov potting compound muaj txiaj ntsig me ntsis. Lub potting txheej thermal kuj yog qhov feem ntau tshwm sim thaum nws yog lub ntsiab lus tseem ceeb nyob rau hauv txoj kev, uas tshwm sim nyob rau hauv tuab -section designs nrog tsawg tsawg - tsis kam txias txoj kev nyob rau sab nrauv.
Daim duab 2.Hauv 15 hli tuab potting seem, hloov ntawm 0.5 W / m·K mus rau 1.5 W / m·K txo cov txheej txheej potting thermal los ntawm kwv yees li ob -feem peb. Txawm hais tias qhov kev txo qis no tseem ceeb nyob ntawm qhov txheeb ze ntawm lwm qhov kev tawm tsam hauv txoj kev thermal.
Qhov twg Thick -Section Potting Thermal Resistance Dominates
Tsis yog txhua txhua potted los ua ke yog rhiab rau lub thermal conductivity ntawm potting compound. Cov qauv tsim hauv qab no qhia txog cov xwm txheej uas cov txheej txheej potting zoo li yuav yog qhov tseem ceeb ntawm kev tiv thaiv thermal:
Potting seem thickness saum toj no 8-10 mm.Hauv qab no ntau yam, lub thermal tsis kam ntawm cov txheej potting feem ntau yog me me txheeb ze rau lwm qhov kev tawm tsam hauv txoj kev. Saum toj no ntau yam, tshwj xeeb tshaj yog thaum lub qhov cua txias yog cov phab ntsa sab nrauv, cov txheej potting feem ntau dhau los ua lub ntsiab lus tseem ceeb.
Fais fab dissipation ceev tshaj 1 W / cm² nyob rau hauv lub potted ntim.At low dissipation density, the temperature differential across the potting layer stays within acceptable limits even at 0.5 W/m·K. As power density increases, the same thermal resistance produces proportionally larger temperature differentials.
Cov cua txias txoj kev topology qhov twg cua sov yuav tsum ua los ntawm cov txheej potting kom ncav cuag qhov cua txias.Nyob rau hauv cov rooj sib txoos uas lub heatsink los yog phab ntsa thaiv yog lub hauv paus cua txias thiab cov potted ntim cais cov khoom ntawm qhov chaw, tsis muaj txoj kev bypass - 100% ntawm cov khoom ntawm cov cua sov dissipated yuav tsum ua los ntawm potting. Hauv cov rooj sib txoos uas cov khoom tuaj yeem ua kom txias los ntawm kev coj, lub dav hlau PCB tooj liab, lossis kev sib cuag ncaj qha nrog lub tsev, qhov kev pab cuam potting raug txo.
Kev siv lub luag haujlwm txuas ntxiv uas tsis muaj thermal cycling nyem.Ib qho kev tivthaiv uas txuas ntxiv mus ze nws qhov kev sib tshuam qhov kub thiab txias txwv accumulates degradation linearly. Kev txo qis ntawm 15℃hauv qhov sib txuas qhov kub thiab txias - ua tiav los ntawm kev xaiv potting compound nyob rau hauv qee qhov geometry - tuaj yeem ua ob npaug rau kev pab cuam lub neej raws li Arrhenius- qauv degradation.
Yog vim li cas Standard Epoxy Thermal Conductivity yog tsawg thiab dab tsi tsa nws
Unfilled thiab maj mam sau epoxy resins muaj thermal conductivity nyob rau hauv thaj tsam ntawm 0.15-0.25 W / m·K. Qhov no yog muaj nyob rau hauv tus ntoo khaub lig- txuas polymer matrix - cov saw hlau polymer yog cov thermal conductors tsis zoo vim tias cov cua sov hloov hauv amorphous polymers feem ntau yog los ntawm kev vibrational zog hloov mus rau cov saw hlau, uas tsis muaj txiaj ntsig piv rau cov ntaub ntawv crystalline. Qhov 0.5–0.7 W/m·K qhov tseem ceeb ntawm cov nplaim hluav taws xob- cov khoom siv hluav taws xob epoxy potting sib txuas sawv cev rau qee cov ntsiab lus muab tub lim - feem ntau yog tib yam inorganic fillers uas ua rau cov nplaim taws -kev ua haujlwm retardant - tab sis ntawm cov khoom ntim khoom ua kom zoo rau kev ua haujlwm thiab cov nplaim hluav taws xob, tsis yog rau thermal conductivity.
Kev ncav cuag 1.5 W / m·K yuav tsum muaj cov khoom ntim ntau dua nrog cov thermally conductive inorganic particles - feem ntau yog txhuas hydroxide, alumina, lossis boron nitride ntawm qhov ntim feem ntau tshaj 50%. Kev lag luam tawm -tawm yog ib qho kev nce siab hauv lub hauv paus viscosity: ib qho qauv xa tawm 1.5 W / m·K feem ntau yuav muaj lub hauv paus viscosity nyob rau hauv thaj tsam ntawm 500,000–1,500,000 cps ntawm 25℃, piv rau 4,000–10,000} cov txheej txheem flare{1. Qhov viscosity ntau yam no yuav tsum muaj kev sib xyaw ua ntej - sib tov, thiab nyiam dua rhuab dispensing ntawm 50℃, kom ua tiav qhov tsis muaj dab tsi - pub dawb nyob rau hauv cov kab noj hniav tsis pub dhau. Lub thermal conductivity nce yog tiag tiag, tab sis nws los nrog cov txheej txheem kev qhuab qhia uas tsis muaj nyob rau hauv tus qauv epoxy potting.
Ib qho tseem ceeb tab sis feem ntau overlooked point:lub thermal conductivity ntawm lub siab puv system tsuas yog ua tiav thaum lub muab tub lim yog uniformly faib rau hauv seem kho.Filler nyob rau hauv lub hauv paus tivthaiv thaum lub sij hawm cia - uas yog ib qho tseem ceeb nyob rau hauv lub tshuab nrog particle densities substituted resin carrier - ua ib tug kho seem nrog sib txawv muab tub lim, thiab yog li ntawd kuj sib txawv thermal conductivity. Thermal conductivity ntsuas ntawm ib qho chaw hauv qhov kho yuav tsis sawv cev rau qhov nruab nrab ntawm qhov nruab nrab, thiab nws yuav tsis sawv cev rau cov seem uas cov muab tub lim - cov khoom siv sab saud tau nchuav. Qhov no tsis yog cov khoom tsis xws luag - nws yog ib qho kev tuav tsis raug. Ua ntej- sib tov lub hauv paus tivthaiv hauv nws lub thawv qub ua ntej qhov hnyav yog tsis xaiv nyob rau hauv siab - muab tub lim.
Daim duab 3.Filler nyob rau hauv E533 lub hauv paus tivthaiv yog qhov tseem ceeb txaus thaum lub sijhawm khaws cia los ntsuas qhov tsis sib xws hauv kev kho thermal conductivity yog tias lub thawv tsis yog kho dua tshiab - sib xyaw ua ntej hnyav.
Cov teeb meem Voids: Vim li cas Degassing yog qhov tseem ceeb hauv cov txheej txheem thermal
Nyob rau hauv tus qauv 0.5 W / m·K epoxy potting compound, entrapped voids txo lub zog dielectric hauv zos thiab tsim qhov chaw muaj kev ntxhov siab. Nyob rau hauv lub thermally conductive compound tsim los ua cua sov, voids muaj ib tug ntxiv thiab loj txim rau: lawv yog thermal insulators embedded nyob rau hauv ib tug thermally conductive matrix.
Lub thermal conductivity ntawm huab cua nyob ib puag ncig yog kwv yees li 0.026 W / m·K - kwv yees li 1/58th ntawm ib puag ncig 1.5 W / m·K matrix. Ib qho khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob. Nyob rau hauv tuab -section fais fab module qhov twg tus tsim lub hom phiaj yog los ua cua sov los ntawm potting mus rau lub enclosure phab ntsa, ib pawg ntawm voids ntawm ib tug tseem ceeb qhov chaw yuav tsim ib lub zos thermal bottleneck uas defeats lub hom phiaj ntawm kev qhia qhov siab dua -conductivity compound.
Lub tshuab nqus tsev degassing yog li ntawd ntau dua nyob rau hauv thermally conductive systems dua li hauv cov txheej txheem. Cov lus sib cav rau degassing tus txheej txheem yog feem ntau dielectric - voids txo cov dielectric zog. Kev sib cav rau degassing lub thermally conductive system yog ob qho tib si dielectric thiab thermal. Txawm hais tias ib daim ntawv thov yuav tsum tau degassing yog nyob ntawm kab noj hniav geometry thiab cov ntsiab lus tsis muaj dab tsi ua tau los ntawm kev ua tib zoo dispensing, tab sis nyob rau hauv siab - zog- ntom potted modules qhov kev xav tias kev nyab xeeb yog qhov yuav tsum tau degassing tshwj tsis yog cov kab noj hniav ua kom zoo tau txais kev pom zoo ntawm cov neeg sawv cev.
Iav Transition Temperature thiab Nws Kev Sib Raug Zoo rau Thermal Performance
Ib qho thermally conductive potting compound yog siv nyob rau hauv ib puag ncig kub los ntawm kev txhais - uas yog daim ntawv thov mob uas txhawb kev xaiv. Lub iav hloov pauv kub (Tg) ntawm cov txheej txheem kho tau txiav txim siab ntawm qhov kub thiab txias ntawm cov khoom siv ntawm cov potting pib hloov. Hauv qab Tg, qhov sib xyaw ua ke yog iav, nruj, thiab ruaj khov. Saum toj no Tg, cov polymer network hloov mus rau lub xeev rubbery nrog txo qis modulus thiab nce CTE sai.
Rau lub potted fais fab sib dhos khiav ntawm qhov kub siab, Tg ntawm qhov sib xyaw tsim kom muaj lub siab ua haujlwm ruaj khov ntawm qhov ruaj khov - tsis yog qhov kev pabcuam kub ntxhov siab tshaj plaws, uas yuav tsum muaj thermal margin hauv qab Tg. Yog hais tias lub potting seem tseem ceeb kub los yog tshaj Tg thaum lub sij hawm ib txwm ua hauj lwm, lub compound yuav nkag mus rau hauv lub load ntawm nws tus kheej thermal expansion, muaj peev xwm tawg lub interface nrog embedded Cheebtsam los yog lub enclosure.
Qhov no txhais tau hais tias Tg qhov yuav tsum tau ua rau lub thermally conductive compound yog txiav txim siab los ntawm cov qauv thermal tso tawm - tshwj xeeb los ntawm qhov ntsuas kub ntawm cov potted seem ntawm qhov siab tshaj plaws nruam load - tsis yog los ntawm qhov ntsuas kub ntawm qhov chaw kaw. In a dense power module where the potting layer reduces junction temperature but the core of the potted mass still reaches 110℃, a compound with Tg of 127℃(with an operating margin of ~17℃) is meaningful. Ib qho chaw nrog Tg ntawm 70℃yuav pib poob qhov kev ruaj ntseg nyob rau hauv cov xwm txheej ntawd.
Yuav ua li cas tus qauv Thermal tsim nyog yuav tsum suav nrog rau cov khoom sib dhos
Ib tug qauv thermal rau lub potted fais fab sib dhos uas tsis suav nrog potting compound thermal kuj yuav systematically underpredict qhov kub thiab txias. Txoj hauv kev kom raug suav nrog:
Txoj kev sib tshuam - mus rau - cov ntaub ntawv thermal tsis kam ntawm txhua qhov sib cais (los ntawm cov ntaub ntawv cov ntaub ntawv).
Kev tiv thaiv kev tiv thaiv ntawm cov khoom siv pob thiab cov khoom siv potting nyob ib puag ncig (nyob ntawm cov ntaub ntub dej thiab cov ntsiab lus tsis muaj nyob ntawm qhov interface).
Cov thermal tsis kam ntawm cov txheej txheej potting los ntawm cov khoom siv saum npoo mus rau thawj tus ciam ciam txias (cov phab ntsa thaiv, heatsink, lossis PCB tooj liab dav hlau).
Qhov kev sib cuag los yog kev sib cuam tshuam ntawm cov potting thiab ciam txias.
Lub thermal tsis kam ntawm qhov txias ciam teb nws tus kheej (enclosure phab ntsa thickness thiab cov khoom, heatsink efficiency).
Nyob rau hauv cov rooj sib txoos uas lub potting txheej thermal kuj yog lub ntsiab lus tseem ceeb - tau txheeb xyuas los ntawm qhov tseeb tias tshem tawm ntawm cov qauv ua kom muaj qhov sib txuas ntawm qhov kub thiab txias hauv qab tus nqi ntsuas - kev xaiv ntawm potting compound thermal conductivity ncaj qha cuam tshuam rau thermal tsim. Qhov no yog qhov xwm txheej uas qhia txog 1.5 W / m·K piv rau 0.5 W / m·K ua rau muaj txiaj ntsig sib txawv hauv kev ntseeg tau.
Thaum Thermally Conductive Potting tsis daws qhov teeb meem
Kev qhia txog 1.5 W / m·K potting compound yuav tsis daws teeb meem kev sib tshuam overtemperature thaum:
Qhov kev sib txuas ntawm cov khoom sib txuas- mus rau - rooj plaub tiv thaiv yog lub ntsiab lus tseem ceeb.Yog hais tias cov khoom nws tus kheej yog lub thermal bottleneck, kev txhim kho cov potting compound tus conductivity muaj marginal nyhuv. Cov qauv thermal tag nrho yuav tsum tau txheeb xyuas kom paub tias qhov twg yog qhov tseem ceeb ua ntej hloov cov ntaub ntawv.
Lub potting seem yog nyias (hauv qab 5 mm).Nyob rau hauv tsawg thickness, lub thermal tsis kam ntawm potting txheej yog me me tsis hais txog ntawm conductivity. Kev qhia txog 1.5 W / m·K los hais txog 5 mm potting txheej ntxiv cov txheej txheem nyuaj yam tsis muaj txiaj ntsig thermal.
Txoj kev txias ntawm lub potting txheej txheej thiab ambient yog qhov txwv tsis pub.Yog hais tias tej yam ntuj tso convection los ntawm lub enclosure nto yog lub thermal bottleneck, txo cov potting txheej kuj txav lub bottleneck ib kauj ruam mus rau sab nraud - nws tsis txo qhov kub thiab txias proportionally.
Cov voids thiab muab tub lim faib tsis tau tswj.Lub thermally conductive compound nrog 10-15% cov ntsiab lus tsis muaj dab tsi yuav ua tsis tau zoo dua li cov qauv sib xyaw nrog xoom voids, vim tias cov voids tsim cov thermal resistances hauv zos uas ntau tshaj qhov kev txhim kho ntau.
Yam khoom lag luam rau Kev Tswj Thermal hauv Thick-Section Potting
E533/H533 yog ib qho hnyav hnyav, ob -cov khoom siv epoxy potting compound xa 1.5 W / m·K thermal conductivity thiab Tg 127℃. Nws yuav tsum muaj ob - theem kho cua sov (80℃× 2 teev + 120℃× 4 teev) los txhim kho nws cov khoom ntsuas. Lub hauv paus tivthaiv (E533) muaj viscosity ntawm 500,000–1,500,000 cps ntawm 25℃- txhua yam ua ntej-sib tov thiab rhuab dispensing ntawm 50℃(qhov sib xyaw viscosity poob mus rau 700–1,500 cps rau kev txhim kho tsis pub dawb.
UL 94 V-0 daim ntawv pov thawj raws li cov ntaub ntawv E120665 (tso npe raws li E-53(Y)/H-53(Y)) yuav tsum tau lees paub nrog Fong Yong Chemical ua ntej specification, raws li kev soj ntsuam raws li lub Kaum Ob Hlis 2025 yuav tsum muaj pov thawj. Cov kws tshaj lij uas xav tau tam sim no UL daim ntawv pov thawj yuav tsum lees paub lub sijhawm rov ua haujlwm ua ntej suav nrog E533 / H533 hauv UL-listed cov khoom kawg.
👉 🔗 E533/H533 Product Page - Technical Data, Thermal Conductivity, Application Notes
Cov lus nug tseem ceeb Engineering
Thaum twg potting thickness puas thermal conductivity specification pib teeb meem?
Raws li cov lus qhia ntxhib, cov txheej potting thermal kuj tseem ceeb txheeb ze rau lwm cov thermal resistances hauv txoj kev thaum lub potted seem tshaj li ntawm 8-10 hli thiab lub zog dissipation ceev tshaj 1 W / cm². Hauv qab no cov theem pib, qhov tsis kam ntawm cov txheej potting feem ntau tsis yog lub ntsiab lus tseem ceeb, thiab nce thermal conductivity ntawm 0.5 mus rau 1.5 W / m·K ua kom tsawg dua 5℃kev txhim kho hauv qhov kub thiab txias. Qhov no yuav tsum tau lees paub los ntawm kev khiav cov lej hauv cov qauv thermal tag nrho rau qhov tshwj xeeb geometry ua ntej txiav txim siab hloov cov khoom siv.
Cov thermal conductivity puas tuaj yeem ntsuas ntawm cov qauv tsim khoom kom paub tseeb tias qhov sib xyaw ua tau raws li tau teev tseg?
Yog lawm, tab sis kev ntsuas yuav tsum tau ua ntawm cov qauv kho tau ua los ntawm cov khoom loj thiab cov degassing, tsis yog nyob rau hauv cov qauv kuaj tau npaj raws li qhov zoo tagnrho. Thermal conductivity nyob rau hauv lub tshuab ua kom puv yog rhiab rau cov ntsiab lus tsis muaj dab tsi thiab muab tub lim. Ib qho piv txwv ntau lawm nrog 5% cov ntsiab lus tsis muaj tseeb thiab cov khoom tsis tiav re-dispersion los ntawm qhov tsis txaus ua ntej- sib tov yuav ntsuas 0.8–1.0 W/m·K es tsis yog 1.5 W/m·K. Kev ntsuas thermal conductivity nyob rau ib ntus ntawm kev tsim khoom- cov neeg sawv cev cov qauv yog qhov tseeb qhov tseeb, tsis yog kev cia siab rau TDS qhov tseem ceeb ib leeg.
Puas yog Tg ntawm potting compound cuam tshuam nws cov thermal conductivity thaum lub sijhawm ua haujlwm?
Thermal conductivity nyob rau hauv cov tshuab uas muaj ntau heev yog tsis tshua muaj rhiab heev rau Tg hloov dua siab tshiab zog. Thawj qhov kev txhawj xeeb saum toj no Tg yog qhov ruaj khov thiab nkag mus - qhov sib xyaw softens, CTE nce los ntawm kwv yees li 2–3 ×, thiab kev thauj mus los ua rau nkag mus rau ntawm potting - cov khoom sib txuas. Thermal conductivity tsis poob qis heev ntawm Tg rau lub kaw lus hnyav vim tias cov khoom muab tub lim (uas nqa cov cua sov feem ntau) nyob hauv qhov chaw. Tg kev txhawj xeeb hauv daim ntawv thov thermally loaded yog txhua yam, tsis thermal conductivity- cuam tshuam.
Cov kauj ruam tom ntej - Hu rau Fong Yong Tshuaj
