Define safe operating limits:
- It is essential to identify the safe operating limits of battery cells, modules, and packs in order to avert the risk of thermal runaway, and the potentially catastrophic consequences to which it could lead. Therefore, batteries need to be subjected to mechanical, electrical, and thermal stresses in order to define their safe operating limits.
- Thermal stability data from thermal stress tests can help define the safe working temperature of the battery
- The evaluation of over-charging and discharging rates allows the maximum safe voltage and maximum safe current to be determined
- The consequences of mechanical stresses and external short circuits (ESC) can be evaluated
Exploring thermal runaways and thermal propagation
- In general, most extreme conditions can result in thermal stress on the battery cell, which can lead to a thermal runaway. Therefore, for the development of safe batteries, it is essential to understand the mechanism of the thermal runaway in a cell, and how it propagates within a module or pack so that appropriate mitigation strategies can be implemented.
The data obtained from the stress tests performed in the BTC-130 and the BTC-500 can be used to model a cell’s predicted thermal behavior. Successive onset temperatures of decomposition of components within the cell can be detected, and the resultant heat released determined. This can help to facilitate a mechanistic understanding of the thermal runaway within the cell. Further insight can also be derived from the external analysis of the composition of any evolved gases collected.
The BTC-500 also enables the triggering of a cell at a specific position within a module to undergo a thermal runaway with a mechanical- or electrical-induced short circuit, while the integrated camera will visually capture the event unfolding. The induced thermal runaway allows the risk of thermal propagation to be evaluated, the magnitude of the thermal event to be characterized, and appropriate mitigation measures to be implemented within the module design to ensure heat dissipation is greater than heat generation.
Characterize differences in cell performance
- The BTC-130 and BTC-500 can be used to characterize the cell performance under more extreme operating conditions. The absolute limit of safe, repeated use can be assessed with the automated cycling of the battery cell until the heat generated by its discharge causes the onset of self-heating. Similarly, puncture tests provide an indication of the structural stability of the cell. The resulting thermal event can also be captured on camera on the BTC-500. These tests enable the safety performance of the cells to be compared.
Find out more in our guide Solutions in Battery Technology Testing: Hazard screening, safety testing and performance characterization
The following are a list of some technical publications which highlight the use of the equipment.
Gaojie Xu, Lang Huang, Chenglong Lu, Xinhong Zhou, Guanglei Cui
https://doi.org/10.1016/j.ensm.2020.06.004(Subscription or purchase maybe required for full access)
Shuai Pan, Changwei Ji, Shuofeng Wang & Bing Wang
https://doi.org/10.1007/s10694-020-01020-x(Subscription or purchase maybe required for full access)
Hendrik Zappen, Georg Fuchs and Alexander Gitis and Dirk Uwe Sauer
https://doi.org/10.3390/batteries6020025(Subscription or purchase maybe required for full access)
Hang Li, Xiangbang Kong, Chaoyue Liu, Jinbao Zhao
https://doi.org/10.1016/j.applthermaleng.2019.114144(Subscription or purchase maybe required for full access)
Hang Li, Chaoyue Liu, Xiangbang Kong,Jun Cheng, Jinbao Zhao
https://doi.org/10.1016/j.jpowsour.2019.226971(Subscription or purchase maybe required for full access)
F. Bianchi; B. Tevenè
https://doi.org/10.1109/I2MTC.2015.7151419(Subscription or purchase maybe required for full access)