Optimization of thermal management in PHEV cell module using heat pipes

Transcription

1 EVS28 KINTEX, Korea, May 3-6, 2015 Optimization of thermal management in PHEV cell module using heat pipes Hyunkyu Choi 1, Yongjung Kim 1, Taesuk Kwon *, Seung Jae Lee 2, JeongHun Seo 2, Yooncheol Jeon 2, Jinho Park 2 1 Hyundai Mobis Co., Ltd, 17-2, 240 Beon-Gil, Mabuk-Ro, Giheung-Gu, Yongin-Si, Gyeonggi-Do, , Korea, yiddol@mobis.co.kr * 2 Hyundai Motors, 772-1, Jangduk-dong, Hwaseong-si, Gyeonggi-do, , Korea

2 Global xev trend I. Overall xevs market sales will reach 12 million by 2020 II. 1. North America, Europe, and Japan will lead the market while China will catch up fast 2. Government regulations will push OEMS to vary line ups and productions Due to government regulation drives over fuel efficiencies and CO 2 emissions, market shares for PHEVs will increase sharply North America Europe China Fuel economy (mpg) CAFE 46.6 CO 2 emission 130 (g/km) Fuel economy 6.9 (l/100km) KABC (2014) 2

3 Power/Energy requirement by xev types I. Based on xev types battery system requirements varies 1. Specific power is focused for HEVs and EVs are Energy focused while PHEVs are in between 2. Optimized design is required for the types with reliabilities Type Power Energy P/E ratio Usable SOC range HEV 15~60kW 1~2kWh 15~30 Narrow PHEV 50~70kW 4~16kWh 4~13 In between EV <100kW <30kWh ~3 >100kW >60kWh ~1.6 Wide 3

4 Heat generation by components I. Heat will be generated due to the efficiencies of each Components 1. Battery system will generate the most heat followed by Motor, Inverter and DC-DC converter 2. Thermal management is the most crucial factor for reliabilities of components EVs main components Heat generation Inverter Ratings Battery DC-DC Converter Inverter Motor DC-DC Converter High Medium Motor Battery system Low 4

5 Why heat pipe I. Heat is transferred through conduction and convection 1. Using latent heat of phase transition between liquid and gas 2. The fluid is circulated through micro channel and by gravity II. Thermal conductivity is much higher 1. Generally one order of magnitude higher than metals 2. Gravity can effect the thermal conductivity of heat pipe III. Shape and operating range can be varied Evaporation Thermal Conductivity 27 Heat in Liquid Phase Gas Phase Heat out Condensation 5

6 Results Pressure drop. I. Pressure drops for each type shows similar to each other II. 1. Power loss due to cooling fins is minimal 2. Pressure drops are small when compared to cooling plate designs Pressure drops within the block are negligible compared to main coolant lines III. Actual experiment data match well with simulation Type 1 Fins Type 2 No fins Type 3 No fins Height Adjusted 6

7 Experimental set up I. Environment Temperature : 45 II. Power input : 5W (2.5W each) III. Coolant temp. : 35 Heat pipe Coolant flow Cooling block Insulator TIM (0.4T) Heater TIM (0.4T) TC3 TC5 TC2 TC4 TC1 * TIM : Thermal Interface Material * TC : Thermal Couple 7

8 Results Cell & heat pipe Temp. I. Maximum cell temperature varies by cooling block type 1. Cooling fins lowered the maximum cell temperature 2. Effect of adjusting height is minimum II. Temperature deviation within the cell increased w/o fins 1. Type 2 cooling block showed the highest 2. Actual experiment showed lower Type 1 Type 2 Type 3 8

9 Results Cell & heat pipe Temp. I. Maximum cell temperature varies by cooling block type 1. Cooling fins lowered the maximum cell temperature 2. Effect of adjusting height is minimum II. Temperature deviation within the cell increased w/o fins 1. Type 2 cooling block showed the highest 2. Actual experiment showed lower 9

10 Conclusions I. Thermal management in battery system is essential II. Complex liquid cooling method needs to be simplified III. Battery cell cooling with heat pipe showed promising IV. Pressure drops for cooling block is relatively small V. Cooling block design is critical in performance 10