EVS28 KINTEX, Korea, May 3-6, 2015 Analysis of the Cooling Performance and Characteristic Using Lithium-ion Battery for Eco-friendly Vehicle Taecheol Jeong Ssangyong Motor Company, 150-3, Chilgoe-dong, Pyeongtaek-si, Gyeonggi-do, Korea, [email protected]
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Analysis of the Cooling Performance and …...EVS28 KINTEX, Korea, May 3-6, 2015 Analysis of the Cooling Performance and Characteristic Using Lithium-ion Battery for Eco-friendly Vehicle
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EVS28KINTEX, Korea, May 3-6, 2015
Analysis of the Cooling Performance and
Characteristic Using Lithium-ion Battery for
Eco-friendly Vehicle
Taecheol JeongSsangyong Motor Company, 150-3, Chilgoe-dong, Pyeongtaek-si,
• Battery performance strongly depends on the temperature• Best performance of Li-Ion cells is reached in a very narrow temperature band• So, Battery thermal management system is needed.
Battery power in vehicle is a function of resistance and control limits
Source: ‘VOLTEC Battery System for Electric Vehicle with Extended Range’, 2011 SAE International, 2011-01-1373‘Electric Vehicle Battery Thermal Issues and Thermal Management Techniques’, 2011 SAE International, Alternative Refrigerant and system efficiency Symposium. NREL
4
Li-Ion Battery Resistance Increases with Decreasing TemperatureCapacity Decreases
• Power decreases with decrease in temperature • Impacts power capability of motor and
vehicle acceleration
• Useful energy from the battery decreases withdecrease in temperature
• Impacts driving range and performance of vehicle
Source: ‘Electric Vehicle Battery Thermal Issues and Thermal Management Techniques’, 2011 SAE International, Alternative Refrigerant and system efficiency Symposium. NREL
Separate cooling loop not required Low mass of air and distribution system No leakage concern No electrical short due to fluid concernSimple design Lower cost / Easier maintenance Low heat transport capacity More temperature variation in pack Blower noise
Models of Mass
Production
GM Volt, Spark EV, Ford Focus,Tesla Model S, etc
Mitsubishi i-MiEVHKMC Ray EV, Sonata HEV, Fluence, Priusetc
• Oil-cooling case is cooler and reaches steady state much more quickly• Liquid cooling/heating is more effective but, could have more mass, has a potential for leaks,
need more components, and could cost more. Maintenance and repair is more involved and costlier. • Indirect liquid cooling is easier to handle than direct liquid cooling.
Source: ‘Battery Thermal Management in EVs and HEVs:Issues and Solutions’, Advanced Automotive Battery Conference. NREL, Las Vegas, 2001
• Liquid Cooling vs Air Cooling
2. xEVs Battery Pack Cooling System Over View
• Discharge Test
Blower On/ Off & Discharge Test
• Test method
1. 2P6S Module 1ea 1C/1.75C/2.5C rate Discharged
2. 16 Points measuring
3. Non-Active Cooling / Active Air Cooling Measuring Temp change
Module
Dummy
Chamber①
1
Measuring Points
2 3
4
5
6
7
8
9
10
11
12
Airflow
②
13
14
15
16
Measuring Points(Amb Temp)
3. Li-Ion Module Discharging Test
• Discharge Test Results without Blower
40A Discharge: 60 min. 70A Discharge : 35 min.
100A Discharge : 25 min.
Tmax ≤ 34 °C and ΔTmax 5.3°C Tmax ≤ 42 °C and ΔTmax 7.6°C
Tmax ≤ 47 °C and ΔTmax 10.9°C
3. Li-Ion Module Discharge Test
• Result of 70A / 100A Discharge without Blower - Module Temp. 40 °C Increasing
• Case of High Current discharge: Cooling needs
• Discharge Test Results with Blower
40A Discharge: 60 min. 70A Discharge : 35 min.
100A Discharge : 25 min.
Tmax ≤ 31 °C and ΔTmax 4.4°C Tmax ≤ 34 °C and ΔTmax 5.9°C
Tmax ≤ 36 °C and ΔTmax 9.5°C
3. Li-Ion Module Discharge Test
• Result of 70A / 100A Discharge with Blower- Module Temp. max 36 °C : Stable
Discharge-
rate
Non Air Cooled (Blower Off) Air Cooled (Blower On)
∆T Min ∆T Max T Max ∆T Min ∆T Max T Max
1C =40A
60min4.4 5.3 34 1.4 4.4 31
1.75C=70A
35min4.7 7.6 42 1.8 5.9 34
2.5C=100A
25min6.0 10.9 47 5.0 9.5 36
• Active Air Cooled has over 15~20% cooling effect than Non-Air Cooled. • The case of non-air cooled, active cooling may needed when over 2.5C discharge because ofincreasing temperature.
3. Li-Ion Module Discharge Test
• Module cooling Test Results Summary
• Profile for 2.5C Discharge 15min. and 3C Charging 11min.
• 2.5C (100Ah*) discharge on 80% SOC Quick Char’g (11Min.)
• *100Ah: High Speed Driving, discharge consecutively 100Ah
Inlet_2 Inlet_1
Module
Outlet
② Temp. on Inlet_1③ Temp. on Inlet_2
④ Temp. on Outlet
⑤ Temp. outside of pack
① Temp. in chamberQuick Discharge Cycle – Quick Charge Cycle
- TModule,max ≤ 44 °C and ΔTModule,max ≤ 23 °C- TModule,max > 40 °C, Cooling with A/C needed
2.5 C
3.0 C
discharge
Charge
15 min
11 min Module 20_1 Module 20_2
방전시작 21 21
방전 종료/충전시작 30 30
충전종료/방전시작 34 34
방전종료/충전시작 41 40
충전종료 44 43
13
Battery Temp
Vehicle Speed
Motor Torque
Initial Temp: 46 °C
Final Temp: 49 °C
• Ambient Temp: 43 °C• Battery Cooling: Air Blower (With A/Con)• EV Mode Driving 50kph 80kph• Battery Current: Discharge 20~30A (50 kph) 40~50 A (80kph)• Test Result: Amb temp 43 °C, 35 min. EV mode Driving Pack Mean Temp: ∆3 °C ↑
Mean: 20 Nm 28 Nm
Speed: 50 kph
Speed: 80 kph
5. EV Temp Profile Test in Hot Chamber
28 Nm
6. Conclusion & Future works
• Conclusion
1. Battery Pack Thermal management Range definition
- Keep 20~40 °C / case of T max 40 °C, Active cooling and Power Limit Strategy are required.
2. Test result of Module Active air Cooling and non-Air Cooling- non-Air Cooling: Discharge 1C/1.75C/2.5C, ∆T min 4.4 ~ ∆T max 10.9 Increasing, - Air Cooling: Discharge 1C/1.75C/2.5C, ∆T min 1.4 ~ ∆T max 9.5 Increasing Active Air Cooled has over 15~20% cooling effect than Non-Air Cooled.
3. Result for Profile Test of Battery Pack Temp. with Air cooling- Pack Air Inlet, Outlet ∆T=4 ℃ / Each Module surface temperature max ∆T=12 ℃, max T=44 ℃- Battery pack temp increasing, active cooling strategy are required. (Related Battery Life)
4. EV Battery Temp Test in Hot Chamber- Amb temp 43 °C, EV mode Driving 35 min. Pack Mean Temp: ∆3 °C ↑
• Future Works
1. Performance Comparison with Cooling with HVAC and Using Cabin air in vehicle level2. Performance Comparison of Battery Pack Temperature changing with Driving Modes