Application of battery needle puncture testing machine in the study of thermal runaway mechanism of lithium-ion batteries

Lithium ion batteries are widely used in various electronic products and new energy vehicles due to their high energy density. However, their safety issues, especially the risk of fire and explosion caused by thermal runaway, have always been a focus of industry attention. Thermal runaway is a violent chain reaction process with complex and rapidly changing internal mechanisms. Among the tools used to study this phenomenon,Battery needle puncture testing machinePlaying a crucial role as a "surgeon" is one of the more direct and effective means of simulating internal short circuits and revealing the mechanism of thermal runaway in the laboratory.

The core of the needle puncture test is to simulate the harsh abuse of internal short circuits in batteries. The testing machine uses a high-precision, programmable electromechanical device to drive a high-temperature resistant steel needle (usually 3-8mm diameter) to pierce the battery cell at a preset speed (such as 10-40mm/s). This process instantly causes the positive and negative electrodes of the battery to be directly connected through the needle body, forming a high current short-circuit point and generating huge Joule heat locally. This controllable and repeatable mechanical abuse effectively reproduces unexpected internal short circuits caused by internal impurities, dendrite growth, or external impact, providing researchers with a standardized and quantifiable triggering condition.

In the study of thermal runaway mechanisms, the value of acupuncture testing machines is far more than just "triggering" accidents, but also lies in their powerful data collection and process reproduction capabilities. A good acupuncture testing machine integrates multiple sensors, which can synchronously monitor and record multiple key parameters during the puncture process, including acupuncture force, battery voltage, short-circuit current, needle body temperature, and temperature changes at multiple locations on the battery surface. These high-precision and high sampling rate real-time data constitute the "black box" for analyzing the evolution process of thermal runaway.

By analyzing these data, researchers can clearly reveal the evolution path of thermal runaway: puncture → internal short circuit → local heat source generation → heat accumulation → large-area melting of the diaphragm → wider internal short circuit → decomposition of active substances, combustion of electrolyte → opening of pressure relief valve → spray valve → fire and explosion. The starting time, temperature threshold, and heat generation rate of each stage can be accurately captured. For example, by analyzing the time difference between voltage dip and temperature rise, the thermal stability of the battery can be evaluated; By using higher temperatures and heating rates, the severity of battery reactions can be determined.

Therefore, the acupuncture testing machine is a bridge connecting macroscopic phenomena and microscopic mechanisms. The experimental data obtained is not only used to verify and improve the safety of battery materials such as more stable positive electrode materials, high heat-resistant separators, and flame-retardant electrolytes, but also provides crucial boundary conditions and verification basis for establishing accurate mathematical models and simulation analysis of battery thermal runaway. Ultimately, these research findings will be fed back into the safety strategy design of battery management systems (BMS), providing theoretical support for early warning and prevention of thermal runaway.

In conclusion,Battery needle puncture testing machineAs an efficient and direct testing tool, simulating abnormal internal short circuit scenarios has opened a door for scientists to deeply study the dynamic process of thermal runaway in lithium-ion batteries, and is a cornerstone equipment for promoting the development of battery safety technology.