UL certification is mainly engaged in product safety certification and operating safety certification business. Its ultimate purpose is to obtain products with safety standards for the market and make contributions to the guarantee of personal health and property safety. As an effective means to eliminate technical barriers to international trade, UL also plays an active role in promoting the development of international trade. As one of the most important performance parameters, safety is one of the core indicators of lithium ion batteries. In the case that lithium batteries are increasingly widely used in power drive,

 whether they have passed UL certification becomes the authoritative basis for identifying and selecting power lithium batteries.

UL testing of power lithium battery

UL's detection and inspection of power lithium batteries are mainly reflected in seven standards, namely, shell, electrolyte, use (over-current protection), liquid leakage, mechanical test, charge and discharge test, and identification.

Among them, mechanical test and charge discharge test are the two core links with many contents.

Mechanical test means that the power lithium battery is under pressure through the transformation of mechanical force and mechanical force. The state displayed is the result of mechanical test.

Mechanical test also includes seven aspects: extrusion, impact, acceleration, vibration, thermal shock, thermal cycle test and altitude simulation. Previously, the ignition test of GM Volt electric vehicle, which attracted wide attention, occurred during the mechanical test of LG lithium battery. Charge discharge test is a test method to judge the performance of lithium battery by the performance of battery under normal and abnormal conditions.

The charge discharge test also includes five aspects: charge discharge cycle, short circuit test, abnormal charge test, forced discharge test and overcharge.

Among them, the charge discharge cycle is a normal test. It is required that the charge discharge cycle of the electric core shall be conducted according to the manufacturer's requirements at 25 ℃. The cycle shall be terminated when the capacity is 25% of the initial nominal capacity or after 90 days of continuous cycle, and no safety event shall occur to the sample.

The other four items are abnormal tests. In short, they are "three over one short": overcharge, overdischarge, overcurrent and short circuit tests. Detect the resistance of power lithium battery to overcharge, over discharge, high current and short circuit respectively. The scientific use of lithium battery charging is a factor that seriously affects the life of lithium battery.

Therefore, the qualified power lithium battery shall pass the above tests to achieve "three no's": no leakage, no fire, no explosion is the qualified battery product.