How to test the safety performance of 18650 lithium batteries: The safety testing of lithium batteries mainly includes the following aspects: it needs to pass safety tests such as overcharging, short circuit, needle puncture, squeezing, and heavy object impact, and the battery should not catch fire or explode. The following are specific methods:
1. Overcharge test
Fully charge the lithium battery and conduct an overcharge test according to 3C standards. When the battery is overcharged, the voltage rises to a certain level and stabilizes for a period of time. When it approaches a certain level, the battery voltage rises rapidly. When it reaches a certain limit, the high cap of the battery breaks and the voltage drops to 0V. The battery does not ignite or explode.
2. Short circuit test
After fully charging the battery, use a wire with a resistance not greater than 50m Ω to short-circuit the positive and negative terminals of the battery. Test the surface temperature change of the battery. The high temperature on the battery surface is 140 ℃. When the battery cap is pulled open, the battery does not catch fire or explode; Acupuncture test: Place a fully charged battery on a flat surface and use a 3mm diameter steel needle to pierce the battery radially. Test that the battery does not ignite or explode; Squeezing test: Place a fully charged battery on a flat surface, apply a squeezing force of 13+1KN by an hydraulic cylinder, and use a steel rod with a diameter of 32mm to press the battery flat. Once the squeezing pressure reaches the stop, the battery will not ignite or explode.
3. Heavy object impact test
After fully charging the battery, place it on a flat surface, vertically place a steel column with a diameter of 15.8mm at the center of the battery, and freely drop a weight of 9.1kg from a height of 610mm onto the steel column above the battery. The battery should not catch fire or explode.
