Key Takeaways:
- Lithium batteries are classified as dangerous goods, requiring adherence to UN 38.3 standards for transport.
- Tests include altitude simulation, thermal, vibration, impact, external short circuit, crush, overcharging, and fast discharge.
- Successful completion ensures batteries are safe for transport via rail, road, or air.
Lithium batteries are classified as dangerous goods class 9. The legal requirements when it comes to transporting them are correspondingly tough.
When transporting lithium batteries or cells by rail, road or air, there is a specific international standard to follow. The transport test 38.3 lists 8 individual requirements that must be met in order to satisfy the standard.
Altitude Simulation
This test simulates conditions in the cargo hold of an aircraft at an altitude of up to 15,000 meters. In this environment the battery will be exposed to a very low air pressure of 11.6 kilopascal for six hours. The test is passed if: the battery shows no loss of mass; the overpressure valve remains closed; the battery housing is free of cracks or leaks and the voltage level differs from the initial value by a maximum of 10%.
Thermal Test
After the altitude simulation test has been completed successfully, experts then take a detailed look at how the lithium battery deals with extreme temperatures. This can put pressure on seals and internal electrical connections.
The batteries are initially stored for a minimum of six hours at 72 degrees Celsius then cooled to -40 degrees Celsius for the following six hours.
In Holo Battery, we do this test procedure in a specially designed thermal shock chamber with 10 cycles each.
Finally, the batteries are stored at room temperature for another 12 hours. To pass the test, all criteria mentioned under altitude simulation have to be met.
Vibration Test
The third part of the UN 38.3 transport test involves putting the battery in a device that shakes between 7 and 200 times per second, also known as Hertz. This test is designed to take a total of 3 hours and it simulates the typical jerking in the truck while driving. The criteria mentioned under altitude simulation also apply in this case.
Impact Test
If you want to avoid possible damage to your battery, the impact test is what you need. The type of lithium battery and its size will dictate how it behaves after a certain level of force is applied. Depending on the battery, 150G/6mS or 50G/11mS may affect the housing. The criteria listed in altitude simulation apply here too.
External Short Circuit Test
In this test, the battery is heated from the outside to 57 degree Celsius before an external short-circuit is caused.
When the battery temperature rises, it may not go past 170°C. After 60 minutes, it must cool back to 57°C.
The test is only passed if no damage to the battery housing can be seen for up to six hours afterward.
Impact and Crush Test
This test is only conducted on cells and simulates exterior damage such as those seen in a car crash.
For this, the type of cell we’re dealing with should be taken into account and a stamping machine used to damage the cells with a pre-assigned depth and size. If done in this way, an electrical short-circuit can occur inside the already broken cells.
To pass, the housing temperature is below 170 degrees Celsius and must not show any cracks or signs of overheating up to six hours after the test.
Overcharging Test
The UN 38.3 transport test dictates an overcharge test for all rechargeable lithium batteries.
For 24 hours, twice the maximum permissible charging current is applied to the battery. If there are no malfunctions during that time, the battery is then left in a secure place for 7 days.
Fast Discharge Test
To ensure safety, the cell is also tested at the rough condition. This is done by subjecting it to a current that exceeds the permitted maximum.
You will need to repeat the process several times. With overcharging, rapid discharge should not damage the battery whatsoever in order to be considered a success in this test.
Conclusion
According to the UN 38.3 guidelines, a battery must undergo 8 tests before being allowed to be transported through rail, road or air.
Holo Battery can carry out all eight UN 38.3 test procedures in the own test center. As a customer, this means that all batteries that you purchase from Holo Battery are required to meet these requirements and are certified accordingly.
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