UL experts speak at lithium-ion battery safety conferences in US and China

The international conference “Battery Power 2011” which just concluded in September 20 in Tennessee, United States.  The conference was focused on the most up-to-date developments and technologies in the battery and power management market.

Two  UL research experts Alvin Wu and Carl Wang gave a presentation on the “Aging Effect(s) on the Safety Behavior of Lithium-ion Batteries”, targeted at OEM design engineers, system engineers, technical and management professionals involved in battery powered products and systems, battery manufacturing, battery technology research and development and power management technology.

Lithium-ion batteries (LIB), having the highest energy density and excellent performance, are one of the dominant off-grid power sources. Despite the focus on performance, the safety of LIB is equally important. Serious incidents involving defective and substandard batteries are topics of very serious public concern.

Initial internal defects that may lead to a safety hazard can be readily detected and prevented via outgoing quality control during the manufacturing process. However, incidents related to LIB usually take place after the battery has been in use for some time. Therefore, it is critical to identify the correlation between aging effects and the battery behavior to address LIB safety issues.

At the conference, Alvin and Carl gave an overview of battery safety behavior and offered examples showing how the LIB safety properties change with aging.

Alvin and Carl shared various tests and their results, including overcharging test, indentation-induced internal short circuit test, hot box test and vibration test to demonstrate how the battery safety behavior change over different aging conditions. In addition, some analytical approaches, such as Differential Scanning Calorimetry (DSC) and Raman Analysis, were also conducted to identify the potential correlation(s) between the changes on material properties to the safety performance of battery. In general, at 45°C LIB batteries will have more apparent aging effect(s) than at ambient room temperature. Such a phenomenon indicates that thermal effect is also a critical factor for battery ageing.

Carl Wong was also invited by China Tsinghua University to present on the topic “Toward a Reliable Li-ion Battery Test Program” at the Beijing 2011 International Forum on Li-ion Battery Technology and Industrial Development held from September 18 to 20, 2011.

For information, please contact batteries@ul.com .