Interfacial Polymer Fusion Mechanics under Altitude Vacuum and Thermal Cycling Stresses
Polymer heat seal integrity depends on controlling interdiffusion depth to resist solvent outgassing during altitude vacuum and thermal stress cycles.
UN 38.3 T1 T2 Testing
Meaning
International safety standards for the transport of lithium batteries require a sequence of environmental simulations to ensure stability during transit. Un 38.3 t1 t2 testing consists of an altitude simulation followed immediately by a thermal test on the same set of samples. These procedures verify that the cells can withstand the pressure changes of a cargo hold and the temperature fluctuations of global shipping routes without leaking or venting.
Sequential Exposure
Low pressure conditions in the first phase check the integrity of the seals against expansion forces. The samples then move to the second phase, where they are cycled between extreme temperatures of 72 degrees and minus 40 degrees Celsius. Combining these stresses in un 38.3 t1 t2 testing identifies weaknesses that might not appear if the tests were conducted on separate groups of batteries.
Safety Verification
Criteria for success include no evidence of mass loss, leakage, venting, or rupture. Technical experts also check for a voltage drop of less than ten percent to ensure the internal electrical structure remains intact after un 38.3 t1 t2 testing. Meeting these requirements is a legal necessity for any company wishing to ship lithium ion products internationally by sea or air.
Sample Quantity
Sample quantities for a standard certification run include ten cells and four battery packs. Documentation showing the results of un 38.3 t1 t2 testing must accompany the shipment to verify compliance with dangerous goods regulations.