Surface temperature evolution and the location of maximum and average surface temperature of a lithium-ion pouch cell under different load profiles.

Transcription

1 Shovon Goutam 1, Jean-Marc Timmermans 1, Noshin Omar 1, Peter Van den Bossche 1, Joeri Van Mierlo 1, Lide Rodriguez 2, Nerea Nieto 2, Maciej Swierczynski 3 1 Mobility, Logistic and Automotive Technology (MOBI), Electrical Engineering and Energy Technology (ETEC), Vrije Universiteit Brussel, Belgium 2 IK4-IKERLAN, Miñano Menor, Spain 3 Department of Energy Technology, Aalborg University, Aalborg, Denmark Surface temperature evolution and the location of maximum and average surface temperature of a lithium-ion pouch cell under different load profiles.

2 Overview Background Objectives Method 2

3 Objectives Methods Reversible Entropic Heat Safety Issues Fire/ Explosion Cause Result Irreversible Heat Internal Resistance Polarization Resistance Heating of the cell Performance Issues Life Cycle Thermal Modelling Development Non destructive validation- Surface Temperature Improved- Cell Design and Thermal Management 3

4 Objectives Methods Surface Temperature Measurement Single Point Measurement Thermocouple Thermistor Spatial Measurement Infrared (IR) Camera Easy to set up for large number of cells Not possible to measure spatial non-uniform distribution Possible to measure Spatial Non-uniform Distribution Difficult to setup for large number of cells 4

5 Objectives Methods Determine the surface temperature evolution under different types of load by using IR camera and contact thermocouples Determine the location of maximum and average surface temperature 5

6 Objecctives Methods Cell Characteristics Rated Capacity: 20 Ah Geometry: Pouch type Chemistry: Lithium-ion, Nickel Manganese Cobalt Oxide (NMC) Continuous Charge- 0.5 I t, 1 I t Continuous discharge- 0.5 I t, 1 I t, 2 I t, 3 I t, 4 I t, 5 I t Characterization Load Profile Micro-Pulse- 2 sec charge at 4 I t and 3 I t 2 sec rest (no load) 2 sec discharge at 4 I t and 3 I t 2 sec rest (no load) 4 K-type thermocouples Test Setup Fluke Ti25 IR Camera Nearly closed environment Ambient temperature- ~23 ᵒC Cell surface painted with dull black color *I t = Capacity (Ah)/ 1 h IEC standard 6

7 Objecctives Method Discharge-1 I t Discharge-0.5 I t Charge-1 I t Discharge- 2 I t, 3 I t, 4 I t 5 I t 7

8 Objecctives Method Discharge at 5 I t (100 A) 31.4 A B 46.1 ~5 Sec ~5 min D C ~20 min (no load) ~10 min 8

9 Objecctives Method Micro-Pulse at 3 I t and 4 I t Micro-Pulse at 3 I t at different SoC 9

10 Objecctives Method Micro-pulse at 4 I t (80 A) 27.4 A 30.6 B ~2 min ~7 min 33.3 D 33.1 C ~50 min ~20 min 10

11 Line 2 Background Objecctives Method Area near the positive tabs fairly represent the location of maximum temperature under both types of load. However, several points can represent location of average temperature. Thus it is difficult to determine the location of average temperature. Therefore, analysis on thermal image has been made 4cm Line 1 Avg. Temp. Box 1cm 1cm Real scale 11

12 Objecctives Method Average temperature with Maximum and minimum temperature (data bar) of 1cm 1 cm (real scale) ATBox, along with global maximum and average temperature plotted against time. Continuous Discharge at 3 I t Micro-Pulse at 3 I t 12

13 Objecctives Method Cell surface temperature distribution under high current continuous charge and discharge along with high current micro-pulse cycling was studied by using contact thermocouples and infrared images During continuous charge and discharge up to 100A, the temperature distribution was more uniform compared to the distribution during micro-pulse cycling Maximum temperature was observed near the positive tab of the cell during micropulse cycling. While during continuous charge and discharge the position of the maximum temperature was observed around the center region of the cell The dependence of the surface temperature on the SoC level of the cell was also investigated and found that the surface temperature does not significantly depends on the SoC level of the cell. A rectangular area of 1cm by 1cm on the cell surface, which can fairly represent the average surface temperature, was identified through data analysis obtained from IR images 13

14 Acknowledgements This research work was funded by the European Union through the NMP Batteries2020 project (Grant agreement GC.NMP / GA nº ) We also acknowledge the support to our research team, MOBI from the Flanders MAKE. 14

15 Thank you. 15