H.E.L Group

BTC-500 Large-scale, battery testing, adiabatic calorimeter

BTC-500 Large-scale, battery testing, adiabatic calorimeter

The BTC-500 (Battery Testing Calorimeter) is a floor-standing adiabatic calorimeter for the safe testing of thermal, electrical, and mechanical stress (abuse) tests on larger battery cells, and small modules. Evaluation of these tests facilitates the assessment of the safety performance of battery cells, enables the battery’s safe operating limits to be defined, and facilitates research and development into the mechanisms of thermal runaway and thermal propagation.

• Characterizing differences in cell performance
• Defining safe operating limits
• Exploring thermal runaways and thermal propagation

Applications

Safety Testing

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.

Performance Testing

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.