How to Scientifically Select Power Lithium Battery with UL Certificate

“UL”, full name- Underwriter Laboratories Inc., is one of world’s most famous safety certification marks. UL is mainly engaged in product and operation safety certification to ensure safe products into market.

As one of most important performance parameters, safety is one of core indicators of lithium-ion battery. With lithium batteries increasingly applying on power, UL certificate has become authoritative standard to distinguish and select Power Lithium Battery.

UL's test on Lithium Battery includes battery shell, electrolyte, use (over current protection), leakage, mechanical test, charge and discharge test, and mark. Among them, mechanical test and charge& discharge test are core.

Mechanical test, that is, making power lithium battery in a pressure state through mechanical force and conversion of mechanical force. State displayed is result of mechanical test. Mechanical test contains crush, impact, acceleration, vibration, heat shock, heat cycle test and altitude simulation. After the above tests, qualified power lithium battery should be no leakage, no fire and no explosion. Previously, mostly concerned GM Volt EV fire happened when mechanical test was carried out to LG lithium battery.

Charge and discharge test to judge lithium battery’s performance through battery reflection in normal and abnormal state. Charge and discharge test consists of charge and discharge cycles, short circuit test, abnormal charge test, forced discharge test and overcharge. Among them, charge and discharge cycle is normal test, requiring battery cells to experience charge and discharge cycles till battery capacity is 25% of initial rated capacity or after 90 days’ continuous cycle. After the cycle, Security incidences should not happen to samples. The remaining four tests are abnormal; in other words, overcharge, over discharge, over current and short circuit test, separately testing whether power lithium batteries are resistant to overcharge, over discharge, high current and short circuit. Scientifically charging lithium battery is a vital factor to affect lithium battery lifetime.