1. Bohyun Moon / Chief Researcher
Korea Transportation Safety Authority 1
정 혁 책임연구원
Korea Automobile Testing and Research Institute(KATRI)
200 Samjon-Ro, Songsan-Myun, Hwasung-Si, Gyeonggi-Do, 18247
Water immersion test
EVS GTR IWG #15
March
Bohyun Moon / Chief Researcher

2. Water immersion test Flooded Cars in Korea annually
More than 1% of all flooding accidents in Korea occur in seawater.

3. Immerse into 0.6M(3.5% NaCl) salt water for 1hr
Water immersion test
Date of entry into force : Feb. 2009
Purpose
Evaluation of traction battery safety under Vehicle immersion accident
Test
Procedure
Criteria
Immersion
Immerse into 0.6M(3.5% NaCl) salt water for 1hr
No Fire &
No Explosion

4. Water immersion test Statistical analysis of Water immersion test
- Water immersion test has been conducted 46 times since 2011
- 6 EV batteries and 1 HEV battery failed EV
HEV
Other
Total
Pass
Fail 2 46 22 6 15 1 28 16

5. Water immersion test DUT Specification of Failed Water immersion test
DUT of test 1 and 2 were same battery.
Test 2 was just retest for the test 1 was conducted properly.
Because the test 1 was first failure we experienced.
Test 3’s battery was LTO cells.
The videos of test 4, 5, 6 will play.
Vehicle V Ah
kWh
Event
Remark 1
BUS
607.5 80
48.6
Fire 2
"
Retest of #1 DUT 3
Bus
607.2 40
24.3
LTO cells 4
706.5
120
84.8
Non-Insulated Case 5
625.6 94
58.8
DUT floated 6
Truck
110.1
364.8
40.2
18650 cells 7
HEV
307.2 10
3.1
Explosion
LFP cells / IPX7

6. Water immersion test DUT Specification of Failed Water immersion test
Test 4’s enclosure was stainless steel and its inside was non insulated.
Test 5 : Due to a lack of ventilation for the gas, Buoyancy increased and the pack
floated.
Test 6’s battery consist of over 5,000 cylinder cells.
Test 7 was water proof battery with LFP cells. The waterproofing broke during
the test and exploded.
Cause of Defect
DUT inside was insufficient distance through insulation (DTI) or insufficient insulation
Passed after improved insulation and extended distance through insulation (DTI)
Vehicle V Ah
kWh
Event
Remark 4
Bus
706.5
120
84.8
Fire
Non-Insulated Case 5
625.6 94
58.8
DUT floated 6
Truck
110.1
364.8
40.2
18650 cells 7
HEV
307.2 10
3.1
Explosion
LFP cells / IPX7

7. Comparison before and after improvement
Water immersion test
Test #4 Video
Cause of Defect
The inside of stainless steel enclosure was not insulated so a path was
generated and an event occurred when immersed.
Passed the test after insulating the case inside.
Comparison before and after improvement

8. Buoyancy increased and pack floated
Water immersion test
Test #5 Video
Cause of Defect
Due to a lack of ventilation for the gas, Buoyancy increased and the pack floated.
Passed the test by making additional ventilation holes and improved insulation.
Buoyancy increased and pack floated

9. Relatively low voltage & high current battery
Water immersion test
Test #6 Video
Cause of Defect
The voltage of this battery was not high compared to other batteries, but
the DUT was sealed as much as possible to slow the entry of water.
The waterproofing broke during the test and exploded.
Passed the test after modified that can be completely immersed.
Relatively low voltage & high current battery

10. Water immersion test Summary
The cause of the event was insufficient insulation and insufficient distance
through insulation (DTI) of inside the DUT.
It is estimated that an event occurs when the above condition is not
satisfied, as well as the magnitude of the voltage and it’s current.
Future work
Water immersion tests will be conducted with differences in salinity from
fresh water to salt water increasing in amount from test to test.

11. Thank you for attention!