Simulation of a Battery Electric Vehicle M. Auer, T. Kuthada, N. Widdecke, J. Wiedemann IVK/FKFS University of Stuttgart 1 2.1.214 Markus Auer
Agenda Motivation Thermal Management for BEV Simulation Model Baseline Range Optimizations of Thermal Management System Preconditioning of Cabin Summary 2 2.1.214 Markus Auer
Motivation Emission-free traveling Limited range Uncertain lifespan of battery Smaller waste heat HVAC of cabin Smart thermal management 3 2.1.214 Markus Auer
Thermal Management for BEV Components Electric motor Inverter Cabin Battery Requirements Limit max. temperature of motor and inverter Satisfy need for cabin comfort Condition battery to operating range [1] [2] [3] [4] [1] fotos.autozeitung.de [2] eal.jku.at [3] gwv-fachverlage.de [4] autogenau.de 4 2.1.214 Markus Auer
Simulation Model - TheFaMoS For reliable prediction a simulation tool was developed Co-Simulation Matlab / Simulink and GT-SUITE Usage of test bench results for calibration Matlab / Simulink Heat flow Speed of coolant pumps AC compressor speed Fan and blower speed Vehicle velocity Ambient conditions GT-SUITE Temperatures Pump power Compressor power Blower power Fan power 5 2.1.214 Markus Auer
p www.ivk.uni-stuttgart.de p Thermal Management System E v a p C o n d C H X P T C H T / L T HX Cond p Chiller PTC Batt Charger Inverter Motor AC HP Batt. Bypass HT-LT AC LP Motor 6 2.1.214 Markus Auer
GT-SUITE Model 7 2.1.214 Markus Auer
Range / km Baseline Range Range is determined with drive until the battery is empty and CADC similar ranges Range in FKFS cycle is slightly lower In very slow NYCC (V ave =11,4 km/h) the range is low due to HVAC consumption Trends of the range depending on temperature are similar for all cycles 85 75 65 55 45 35 CADC FKFS NYCC 25-2 -1 1 2 3 4 T amb / C dummy 8 2.1.214 Markus Auer
DRange / % Circulating Air Quota (5%) Speed control of the blower is not changed Usage of a mixer which is set to approximately 5% recirculating air At -18 C and 35 C, the benefits of recirculating air are clearly visible At 1 C and 25 C, the effect is negligible 14 12 1 8 6 4 2 CADC FKFS NYCC -2-1 1 2 3 4 T amb / C dummy 9 2.1.214 Markus Auer
DRange / % Usage of Waste Heat to Heat the Cabin The baseline uses a cabin heat exchanger to use waste heat from the motor circuit If this usage is suppressed and the heat deficit compensated by the PTC and the heat pump, the range drops significantly If a synchronous motor is used, the effect is smaller since the efficiency is higher -2-4 -6-8 CADC FKFS NYCC -1-2 -1 1 2 3 4 T amb / C dummy 1 2.1.214 Markus Auer
DRange / % Heat Pump The baseline uses a heat pump for the heating of the cabin If the heat pump is turned off and the heat deficit is compensated by the cabin heat exchanger and the PTC, the range decreases The elimination of the heat pump is more drastic than the elimination of the cabin heat exchanger -1-2 -3-4 -5-6 CADC FKFS NYCC -7-2 -1 1 2 3 4 T amb / C dummy 11 2.1.214 Markus Auer
DRange / % Waste Heat Usage for Heating of Battery In the baseline the PTC is below 1 C used to keep the battery at operating temperature If waste heat is used instead, the range is increased Range is on average increased by about 2.5% 3.5 3. 2.5 2. 1.5 CADC FKFS NYCC 1. -2-1 1 2 3 4 T amb / C dummy 12 2.1.214 Markus Auer
a / W/m 2 K DRange / % www.ivk.uni-stuttgart.de Insulation of Battery 13 5 45 4 35 3 25 2 15 1 5 The battery loses / gets a lot of heat from the environment, if it is not insulated If α is increased from W/m²K to 1 W/m²K, the range 1.752decreases.645.41 1.89 Q Batt=>Amb /Q Batt -2-1 1 2 3 4 T amb / C 2 1.75 1.7 1.5 1.25 1.75.5.25 1-1 -2-3 -4-5 CADC FKFS NYCC -6-2 -1 1 2 3 4 T amb / C 2.1.214 Markus Auer dummy
DRange / % Combination of Single Optimizations Relative to baseline Recirculating air 5% Lightened motor Adapted cabin mean temperature with compensation of heat deficit Usage of waste heat to heat the battery 2 15 1 5 CADC FKFS NYCC -2-1 1 2 3 4 T amb / C dummy 14 2.1.214 Markus Auer
DRange / % Range / km www.ivk.uni-stuttgart.de Combination of Single Optimizations As before, only with respect to baseline without cabin heat exchanger and heat pump Significant advantages can be seen at low temperatures 3 25 CADC FKFS NYCC 9 8 CADC FKFS NYCC 2 7 15 1 5 6 5 4 15-2 -1 1 2 3 4 T amb / C 3-2 -1 1 2 3 4 T amb / C 2.1.214 Markus Auer
Consumption / kwh DConsumption / % www.ivk.uni-stuttgart.de Preconditioning of Cabin Total energy consumption increases with preconditioning With preconditioning at low temperatures, the consumption can be significantly reduced 6.5 6. with consumption for preconditioning w/o consumption for preconditioning 5 5.5 5. -18 C ambient -5 16 4.5 4. -2-1 1 2 3 T Cabin,start / C dummy -1 CADC FKFS NYCC -15-2 -1 1 2 3 4 T amb / C 2.1.214 Markus Auer
Summary Simulation model of a battery electric vehicle Thermal management system with AC and heat pump Baseline range Potential for single optimizations Potential of combination of single optimizations Effect of preconditioning of cabin on consumption 17 2.1.214 Markus Auer
Acknowledgement The authors would like to thank Forschungsvereinigung Verbrennungskraftmaschinen e. V. Gamma Technologies Members of the working group 18 2.1.214 Markus Auer
Thank you for your kind attention! Questions? 19 2.1.214 Markus Auer
Backup 2 2.1.214 Markus Auer
Gradient [%] www.ivk.uni-stuttgart.de Speed [km/h] FKFS Lap (Stuttgart, Germany) 21 14 FKFS 12 1 8 6 4 2 2 15 1 5-5 -1-15 5 1 15 2 25 3 35 4 Time [s] 2.1.214 Markus Auer
Gradient [%] www.ivk.uni-stuttgart.de Speed [km/h] NYCC 22 14 NYCC 12 1 8 6 4 2 2 15 1 5-5 -1-15 1 2 3 4 5 6 Time [s] 2.1.214 Markus Auer
Gradient [%] www.ivk.uni-stuttgart.de Speed [km/h] 23 14 12 1 8 6 4 2 2 15 1 5-5 -1-15 2 4 6 8 1 12 Time [s] 2.1.214 Markus Auer
Gradient [%] www.ivk.uni-stuttgart.de Speed [km/h] CADC 24 14 CADC 12 1 8 6 4 2 2 15 1 5-5 -1-15 2 4 6 8 1 12 Time [s] 2.1.214 Markus Auer