Thermal Test T.2

Thermal Stressing

Lithium batteries can be exposed to severe temperature fluctuations when they are shipped by air, sea, or road through different climate zones. To ensure that they remain safe under these conditions, safety standards require that cells undergo rigorous thermal cycling tests. The thermal test t.2 protocol subjects the battery to ten complete cycles of extreme high and low temperatures.

This cycling creates significant mechanical stresses within the cell due to the different expansion rates of the metal casings and the internal active materials. Technicians monitor the battery for any signs of physical damage or degradation of the seals during and after the test. This testing is essential to verify that the cell can survive these temperature changes without releasing hazardous electrolytes or catching fire.

Material Stability

Extreme temperatures can cause the delicate polymers and active materials inside a lithium cell to degrade or fail mechanically. During the thermal test t.2, the polymer separators and cell seals are subjected to severe expansion and contraction forces. If the materials are not designed to handle these changes, the separator can rupture or the seal can leak, causing an internal short circuit.

This test demonstrates that the cell chemistry and mechanical construction are robust enough to withstand these thermal stresses. Sourcing teams use these test reports to evaluate the quality of the materials used in the cells they procure.

Regulatory Compliance

Passing this thermal test is a mandatory requirement for obtaining safety certification under international dangerous goods transport regulations. The thermal test t.2 is one of the eight core tests in the UN 38.3 manual that all lithium batteries must pass before shipping. Sourcing contracts almost always require that the supplier provide a certified test summary showing compliance with this standard before any products are delivered.

This requirement helps ensure that the batteries can be safely transported across global supply chains without posing a risk of fire or explosion. Having this certification also helps protect the manufacturer from product liability claims.