Testing Data of Cell Thermal Runaway and Analysis of Gas Production,
Testing Data of Cell,

▍What is cTUVus & ETL CERTIFICATION?

OSHA (Occupational Safety and Health Administration), affiliated to US DOL (Department of Labor), demands that all products to be used in workplace must be tested and certificated by NRTL before being sold in market. Applicable testing standards include American National Standards Institute (ANSI) standards; American Society for Testing Material (ASTM) standards, Underwriter Laboratory (UL) standards, and factory mutual-recognition organization standards.

▍OSHA, NRTL, cTUVus, ETL and UL terms definition and relationship

OSHA: Abbreviation of Occupational Safety and Health Administration. It is an affiliation of US DOL (Department of Labor).

NRTL： Abbreviation of Nationally Recognized Testing Laboratory. It is in charge of lab accreditation. Up to now, there are 18 third-party testing institutions approved by NRTL, including TUV, ITS, MET and so forth.

cTUVus： Certification mark of TUVRh in North America.

ETL： Abbreviation of American Electrical Testing Laboratory. It was established in 1896 by Albert Einstein, the American inventor.

UL： Abbreviation of Underwriter Laboratories Inc.

▍Difference between cTUVus, ETL & UL

▍Why MCM?

● Soft Support from qualification and technology: As the witness testing lab of TUVRH and ITS in North American Certification, MCM is able to perform all types of testing and provide better service by exchanging technology face to face.

● Hard support from technology: MCM is equipped with all testing equipment for batteries of big-sized, small-sized and precision projects (i.e. electric mobile car, storage energy, and electronic digital products), able to provide overall battery testing and certification services in North America, covering standards UL2580, UL1973, UL2271, UL1642, UL2054 and so forth.

The safety of energy storage system is a common concern. As one of the critical components of energy storage system, the safety of lithium-ion battery is particularly important. As thermal runaway test can directly evaluate the risk of fire occurring in energy storage system, many countries have developed corresponding test methods in their standards to assess the risk of thermal runaway. For example, IEC 62619 issued by the International Electrotechnical Commission (IEC) stipulates the propagation method to evaluate the influence of thermal runaway of the cell; Chinese national standard GB/T 36276 requires thermal runaway evaluation of the cell and thermal runaway test of the battery module; The U.S. Underwriters Laboratories (UL) publishes two standards, UL 1973 and UL 9540A, both of which assess thermal runaway effects. UL 9540A is specially designed to evaluate from four levels: cell, module, cabinet, and heat propagation at installation level. The results of thermal runaway test can not only evaluate the overall safety of the battery, but also allow us to quickly understand the thermal runaway of cells, and provide comparable parameters for the safety design of cells with similar chemistry. The following group of testing data for thermal runaway is for you to understand the characteristics of thermal runaway on each stage and the materials in the cell.Stage 3 is the electrolyte decomposition stage (T1~ T2). When temperature reaches 110℃, the electrolyte and the negative electrode, as well as the electrolyte itself will occur a series of decomposition reaction, producing a large amount of gas. The continuously generating gas makes the pressure inside the cell increase sharply, reaching the pressure relief value, and the gas exhausting mechanism opens (T2). At this time, much gas, electrolytes and other substances release, taking away part of the heat, and the temperature increasing rate becomes negative.