Use steel nails to penetrate the battery, simulate an internal short circuit, and conduct a test to confirm if the battery is smoking, catching fire, or breaking.
To test this, it is not an option to manually drive a nail into a lithium-ion battery due to the risk of injuries from the flying nail. Therefore, a pinning test machine is necessary.
How Lithium-ion batteries cause internal short circuit during nail penetration process?
According to current understanding, the basic process of internal short circuit caused by lithium-ion batteries during the nail penetration process is as follows: Firstly, the Joule heat generated by the internal short circuit causes a rapid increase in the local temperature of the battery.
What is a needling test for a lithium ion battery?
The needling test is not only a safety test for a lithium-ion battery, but also an important test to understand the basic nature of the battery. In the normal state, the positive and negative electrode sheets of a lithium-ion battery are insulated by a polymer insulating film – the diaphragm – in the organic electrolyte.
Conducted a nail penetration test on a 18650 lithium-ion battery with a capacity of 22 Ah and found that as the nail penetration rate increased, the probability of the lithium-ion battery passing the safety test increased.
The short circuit inside the battery should be artificially triggered and observed for a period of time. The nail penetration test is shown in Figure 1. If the battery does not catch fire, smoke or explode, it will pass the nail penetration test. Otherwise, it will not pass.
The Nail Penetration Test is a safety test that tests the internal short circuit tolerance of lithium-ion batteries. It is a method used for this purpose.