Reliability of New SiC BJT Power Modules for Fully Electric Vehicles

Transcription

1 18th Internatinal Frum n Advanced Micrsystems fr Autmtive Applicatins (AMAA 2014) Berlin, 24. June 2014 Reliability f New SiC BJT Pwer Mdules fr Fully Electric Vehicles 1, Eberhard Kaulfersch 2, Klas Brinkfeldt 3, Klaus Neumaier 4, Olaf Zschieschang 4, Dag Anderssn 3, Sven Rzepka 1 alexander.tt@enas.fraunhfer.de, Technlgie-Campus 3, Chemnitz, Germany 1 2 Nantest und Design GmbH 3 Swerea IVF AB 4 Fairchild Semicnductr GmbH Page 1 Prf. B. Michel, Prf. S. Rzepka

2 Prject duratin: Oct'12 Sep'15 I. COSIVU prject Overview Prject bjectives: Develpment f a nvel electric drivetrain system architecture by realizing a smart, cmpact, and durable singlewheel drive unit including: integrated electric mtr 2-stage gear system inverter with SiC based pwer electrnics nvel cntrl and health-mnitring system with wireless cmmunicatin advanced ultra-cmpact cling slutin Validatin platfrm: cmmercial vehicle (VOLVO) + passenger car (Elaphe) E-Mtr Inverter building blck Pictures: Vlv CE Fraunhfer IISB Inverter Pwer mdule Page 2 ENAS + IISB

3 II. SiC pwer mdule General infrmatin Pwer mdule in half-bridge cnfiguratin with full SiC cmpnents: 4x SiC biplar junctin transistrs (BJT) frm FCS 4x SiC dides frm Cree 1200V, 50A (dide: 54A) Substrate: DCB with aluminum nitride (AIN) as ceramic islatr Lead-free slder; Alu wirebnds (E: 300µm, B: 150µm) Encapsulatin: epxy mld cmpund (EMC) FCS SiC pwer mdule: SiC biplar junctin transistr: Duble-sided cled SiC pwer mdule: Page 3

4 II. SiC pwer mdule Schematic 3 pwer mdules in parallel per phase leg Pwer mdule (half bridge cnfiguratin) Inverter with 3 phase legs Page 4

5 III. Reliability General apprach fr reliability assessment f pwer mdule Experiment Pwer mdule Simulatin Nrms & Standards Missin Prfile Material Data Gemetry Data Test Cnditin / Lad Prfile Reliability Testing (APCT) Failure Analysis Test Evaluatin FE Simulatin (e.g. therm-mechanical) Damage Mdel Cmparisn experimental results with failure mdels frm simulatin results Page 5 Page 5 Lifetime estimatin

6 III. Reliability FE simulatin: Gemetry mdel FE simulatin targets: Investigatin f mechanical stress cncentratin and accumulating plastic and creep strain induces by: Glbal mdel Mld cmpund Pin BJT Manufacturing prcess (sldering f DCB, transfer mlding) Internal and external thermal lads Replicatin f the crrespnding physical effects Simulatin mdel: Ralf Döring Leadframe Dide Nn destructive CT inspectin and pwer mdule determinatin f input fr 3D simulatin Page 6

7 III. Reliability FE simulatin: Gemetry mdel Lcal gemetry mdel f wire bnd: Psitin f lcal bnd wire mdel Psitin f bnd wire derived frm CT scan: 3D image f wire-bnds: Page 7

8 III. Reliability FE simulatin: Gemetry mdel Chesive zne apprach fr wire bnd: Gemetry infrmatin derived frm 3D digital micrscpe images Crack grwth law (Paris and Erdgan): Linear tractin-separatin respnse: Bnd wire base (200µm) Chesive zne area (1µm) Metallizatin (10µm) Die (380µm) Page 8

9 III. Reliability FE simulatin: Calibratin Calibratin result: Gd cmpliance between warpage measurement and simulatin Warpage measurement results: OMI Equinx: Simulatin results: Page 9

10 III. Reliability FE simulatin: First simulatin results FE simulatin results: Quantifying f creep strains in the die attach f the SiC dies accumulated ver the prcess steps and thrugh thermal cycling already by glbal mdel Significant strains and stress can be bserved in the die attach Results indicate that creep strain are primarily influenced by the high CTE mismatch between DCB and SiC dies Accumulating equivalent creep strain (=failure criterin) in die attach may lead t Simulatin: slder Eberhard fatiguekaulfersch Equivalent creep strains accumulated after ne thermal cycle (-40 t 150 C) Page 10

11 III. Reliability FE simulatin: First simulatin results FE simulatin results: Mnitring f mechanical stress cncentratin and plastic defrmatin at the bnd wires have been perfrmed by using the lcal mdel Strain values are significant, but cnclusins can nly be made tgether with the testing results Further investigatins are needed Simulatin: Eberhard Kaulfersch Page 11

12 III. Reliability Active pwer cycling: Test bench adaptin Starting pint: Existing APC test bench dedicated t MOSFET / dide based pwer mdules APC test bench at : 1. Sample hlder 2. Electrical HW / cnnectin plan 3. LabVIEW cntrl SW Page 12 Prf. B. Michel, Prf. S. Rzepka

13 III. Reliability Active pwer cycling: New sample hlder design Fr single-sided + duble-sided cling Insulatin DUTs (pwer mdules) Upper flw bdy Clant in- and utlets Pressure plate Main (lwer) flw bdy Page 13 Prf. B. Michel, Prf. S. Rzepka

14 III. Reliability Active pwer cycling: Thermal analysis f cling bdy Thermal-fluid analysis f cling bdy Simulatin f single-sided cling case Pwer mdules replaced by simple heat surces (130W@50A/1,3V) with cnstant pwer Emplyment f steady-sate simulatin Fluid flw rate is determined by the pump system curve Pwer planes: 8x130 W = 1040 W Outlet: n BCs Inlet: dv/dt refers t pump curve (see belw) T_in = cnst = 60 C Surfaces: adiabatic, i.e., heat transfer established nly by liquid cling Pump curve f used thermstat (Level 4): Prperties f flw bdy: Prperties f clant (Silicn il Kry 51): Chasis material (Alu) Sealing material (Nafln 100) Ceef. f thermal cnductivity 313,0 W/mK 0,25 W/mK Density 19281,0 Kg/m ,0 Kg/m 3 Deff. f spec. heat 131 KJ/KgK 1300 KJ/KgK Page 14

15 III. Reliability Active pwer cycling: Thermal analysis f cling bdy Simulatin results: Temperature cntur plt and is-thermal indicates lw temperature gradient amng the heat surces Surces 2 6 are at the same max. temperature (within 1 k deviatin) Surce 1 and surce 8 max temperatures are slightly belw The max temperatures shw a temperature rise abve ambient f less then 25 K Mid plane cntur plts (tp view): Tp plane (heat surces) cntur: Page 15

16 III. Reliability Active pwer cycling: Cnnectin plan Change Over Switch SiC pwer mdules Test 1 Test 2 IGBT mdule with gate driver DUT1 DUT2 Base Driver Cnst. Current Surce Base Driver Cnst. Current Surce Electrnic lad & pwer supply Cnstant current surce Base driver DUT3 Base Driver Cnst. Current Surce Pwer Supply Electrnic Lad DUT4 DUT5 Base Driver Cnst. Current Surce Base Driver Cnst. Current Surce DAQ DUT6 Base Driver Cnst. Current Surce DUT7 Base Driver Cnst. Current Surce DUT8 Base Driver Cnst. Current Surce Page 16 Prf. B. Michel, Prf. S. Rzepka

17 IV. Nvel cling cncepts Investigatin f duble-sided cling cncept ( 2 COOL) by Swerea IVF: Thermal cmputatinal fluid dynamics (CFD) analyses n simple inline pin-fin structure as well as n spnge-like structure Clant flw: 5 15 l/min; Temp.: 20 C Heat surce: Single-sided scenari, 30W each Results: see picture n the right; higher pressure drp fr spnge-like structure Cnclusin: Further imprvements needed in terms f reduced height and tilted spnge structure fr better vertical mixing f clant Pin-fin structure Spnge structure Page 17

18 V. Next steps in COSIVU (reliability wrk fr SiC pwer mdule) FE simulatin: Simulatin f active pwer cycles fr single-sided pwer mdule Likewise, FE simulatin fr duble-sided cled pwer mdule Simulatin at system level (inverter building blck) with detailed sub-mdels f critical cmpnents (pwer mdule, current sensr, ) Active pwer Cycling: Test bench adaptatin: Sample hlder: Thermal fluid analysis n duble-sided cling system Cnnectin plan / HW: i) Finalizatin ii) Fully galvanic decupled cnstant current surces iii) Base driver Adaptin f LabVIEW cntrl sftware Pwer cycling tests and failure analysis n single-sided and duble-sided cled pwer mdules Page 18 Prf. B. Michel, Prf. S. Rzepka

19 Thank Yu fr Yur attentin! Page 19 Prf. B. Michel, Prf. S. Rzepka