1. Moon Bo-hyun / 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 #17
Jan
Moon Bo-hyun / Chief Researcher

2. Water immersion test Failure case #1
- Fires occurs after intense venting gas release
Multiple holes found outside of the case
Nominal Voltage : V DC
Capacity : 36.8 kWh

3. Water immersion test DUT analysis : Fire occurs module
The DUT was connected by brine due to the narrow module spacing

4. Water immersion test DUT improvement Before After
The module’s location can not be changed due to design
- Therefore, the live parts are insulated as much as possible so that the venting gas which is generated actively is not ignited
Extend the distance between relays(66mm -> 150mm)

5. Water immersion test DUT improvement Before After
The module can not be changed due to design
- Therefore, the live parts are insulated as much as possible so that the venting gas which is generated actively is not ignited
Extend the distance between relays(66mm -> 150mm)
DUT improvement
Before After

6. Water immersion test Module improvement + Before After
Ignited on the exposed electrodes of cell
Parts for preventing the exposure of cell’s electrode were added to each cell
Insulating the exposed live parts can prevent the event (fire or explosion)

7. Water immersion test Failure case #2
- The REESS for L7 category (72V DC)
No cooling and no venting holes
Therefore, the REESS can explode if venting occurs inside

8. Water immersion test Failure case #2
- 54P cells / module x 20S modules / Pack
20 modules are connected in series and the beginning and end of the module are close
Exploded due to the narrow distance of the bus bars

9. Water immersion test Summary
1. A Safe immersion test scenario is that the cells are discharged each other.
Otherwise, flammable gases are generated when the reaction starts in module units or pack units. If the live parts are insulated, ignition or explosion may not occur.
2. If the battery such as failure case #2 was used without any improvement,
which could be a direct danger to the occupants and the surrounding environment. However, it was filtered by the immersion test.

10. Thank you for attention!