1. Japan research of thermal propagation test
EVS-GTR IWG#16

2. Reminder of Japan research
To assess repeatability, reproducibility, practicability, etc. of the test procedure discussed during Phase 1, different organizations inside Japan conducted thermal propagation test under same conditions according to para 23 of GTR No.20 Part I (Though the test procedure does not represent the scenario intended in Japan).
GTR No.20 Part I
Institutes A B
Sample X ←
Initiation method
Nail
Number 1 3
Institute A
Institute B
Assess reproducibility
Assess repeatability

3. Reminder of Japan research results
Some parameters have repeatability/reproducibility but some parameters doesn’t have.
Sample 1 2 3 4
Repeatability/
Reproducibility
Institute A B
Thermal runaway occurs/ not occurs
Occurred ←
High
Thermal propagation occurs/ not occurs
Not occurred
Fire and explosion occurs/ not occurs
Voltage drop of initiation cell
JPN presentation in IWG#15 P9
Variations were observed.
Temperature of Initiation cell and adjacent cell
JPN presentation in IWG#15 P9, 10, 11
Pressure of pack
JPN presentation in IWG#15 P12
Sample1
Sample2

4. Japan new research
To assess the test procedure of heater, an organization inside Japan conducted thermal propagation test under same conditions according to para 23 of GTR No.20 Part I.
Assess repeatability
Institutes C
Sample Y
Initiation method
Heater
Number 2
Sample 1 2
Thermal runaway of initiation cell occurs /not occurs
Thermal propagation occurs / not occurs
Fire and explosion occurs / not occurs
Voltage drop
Temperature rise
Pressure of pack :
GTR No.20 Part I
Institute C

5. Conditions Condition Reason Heater Shape Planate Planate or rod
Reference
(GTR No.20 Part I)
Heater
Shape
Planate
Planate or rod
Same as GTR No.20 Part I condition.
Heating area
25×25mm
Less than cell surface ↑
Power
Maximum
Stop temp.
400ºC
[300ºC]
Because of heater spec
Position
Directly contacting cell surface ←
SOC
100%
90/95% or more
Temperature
Depends on test place
25±2ºC
Institute C doesn’t have air conditioner in test booth.
Position of target cell
Cell that is surrounded by other cells
(Page6)
Manipulation of pack
Without coolant -
Difficult to conduct test with coolant (Page7)
Voltage and thermocouple points
Target cell, surrounding cells and various points inside pack
To detect thermal runaway of trigger cell and surrounding cells.

6. Conditions Position of target cell Target cell: Cell15 in module2.
Set heater in the center of cell15
Target cell
（Cell15 in Module2）
Module2
2 parallels 16 series
Plastic
Plate
Cooling Plate
Insulator
Parallel 3 4
Cell 1 2 5 2 11 12 13 14 15 16 17 18 31 32 ‥‥ ‥‥
Module1 6
Cell
Series
Module2
Heater

7. Conditions Manipulation of pack
Without coolant. Difficult to assemble cooling piping due to heater and thermal insulator. Critical issue as a regulatory test.
Coolant
Set insulator and heater
Cooling plate
Heater
Cell
Plastic plate
Packing
Insulator
Cannot
assemble
Coolant

8. Variations were observed
Research results
The results of two tests show good repeatability in overall phenomena while slight variations in detailed measurements.
Sample 1 2
Repeatability
Institute C
Thermal runaway occurs/ not occurs
Occurred ←
High
Thermal propagation occurs/ not occurs
(Only within module2)
Fire and explosion occurs/ not occurs
Not occurred
Voltage drop
P9, 10
Variations were observed
Temperature inside pack
P11
Pressure of pack
Measured
Cannot measured
Cannot confirmed
Sample2

9. Results (Voltage near initiation cell)
Slight variations in voltage drop profile and timing (i.e. thermal propagation speed) were observed.
Module2
Sample1
Initiation cell
15,16
13,14
17,18
11,12
19,20
Voltage (Sample1) / V 13 16 17 14 15 11 12 18 19 20
Voltage (Sample2) / V
Sample2
15,16
13,14
17,18
11,12
19,20
These data were acquired under the Project for the Lithium-ion Battery Advanced Technology Development, entrusted by the New Energy and Industrial Technology Development Organization (NEDO).
Voltage drop start point of initiation cell
Time / min

10. Results (Voltage far from initiation cell)
Slight variations in voltage drop timing (i.e. thermal propagation speed) were observed.
21-32
Module2
Initiation cell
21,22
Sample1
1-10
9,10
23,24
7,8
25,26
5,6
27,28
29,30
3,4
1,2
31,32
Voltage (Sample2) / V
Voltage (Sample1) / V
21-32
21,22
Sample2 1 2 9 10 21 22 31 32 ・・ ・・ ・・ ・・
1-10
9,10
23,24
7,8
25,26
5,6
27,28
29,30
3,4
These data were acquired under the Project for the Lithium-ion Battery Advanced Technology Development, entrusted by the New Energy and Industrial Technology Development Organization (NEDO).
1,2
31,32
Voltage drop start point of initiation cell
Time / min

11. Results (Module2 temperature)
Variations in maximum temperature and profile were observed in each sample.
Module2 2 7 13 16 17 8 14 15 18 27 28 31 32 ‥
Cell 1
These data were acquired under the Project for the Lithium-ion Battery Advanced Technology Development, entrusted by the New Energy and Industrial Technology Development Organization (NEDO).
Sample1
Temperature (Sample2) / ℃
Temperature (Sample1) / ℃
Sample2
Voltage drop start point of initiation cell
Time / min

12. Difference of module2 temperature
Inside materials (electrode, foil, etc.) of several cells were released in sample1. →Couldn’t measure hot point or thermocouples might have been peeled off.
Sample1
Sample2
Most of the materials inside cells were released
Module2
Module2

13. Summary
Assessed repeatability and practicability of thermal propagation test (Heater).
Good repeatability in overall phenomena while slight variations in detailed measurements.
Need to discuss acceptable level of variation and manipulation.

14. Future Plan
Further investigation to know what scene should be simulated in this test.
Assess new initiation methods whether it can simulate this scene.
2017
2018
2019
2020
IWG
Japan Research
#14
#15
#16
#17
Report
Report
Repeatability and reproducibility test (Ｎａｉｌ)
Repeatability test (Heater)
Field data investigation
New initiation method test (Laser)

15. Thank you for your attention

16. Q&A Questions Answers JRC 5
Slide No.
Questions
Answers
JRC 5
Based on which rationale did you define the size of the heater?
We selected heater according to GTR No.20 Part l condition. “Heating area of heater contacting the cell shall not be larger than area of cell surface wherever possible.” 10
What does slight variation in thermal propagation speed mean? Can you please quantify?
It means the difference of voltage drop timing between sample1 and 2.
When thermal runaway occurs, the cell voltage drops.
Difference of voltage drop timing is almost same as the difference of thermal propagation speed.