Thermal accelerating-rate calorimeter

In a testing context, it refers to the first detection of exothermic-activity on the thermogram. The differential scanning calorimeter (DSC) has a scan rate of I0°C/min, whereas the accelerating rate calorimeter (ARC) has a sensitivity of 0.02°C/min. Consequently, the temperature at which thermal activity is detected by the DSC can be as much as 50°C different from ARC data. 

D. I. Townsend and J. C. Tou, Thermal Hazard Evaluation by an Accelerating Rate Calorimeter, Thermochimica Acta (1980), 37 1-30. 

ARC = Accelerating Rate Calorimeter (Columbia Scientific Instrument Corp.) DSC = Differential Scanning Calorimeter DTA = Differential Thermal Analysis RC1 = Reactor Calorimeter (Mettler-Toledo Inc.) RSST = Reactive System Screening Tool (Fauske and Associates) VSP = Vent Size Package (Fauske and Associates) ... 

Townsend, D.I. and Tou, J.C. (1989) Thermal hazard evaluation by an accelerating rate calorimeter. Thermochim Acta 37 1-30. 

The experimental techniques described above of charge—discharge and impedance are nondestructive. Tear-down analysis or disassembly of spent cells and an examination of the various components using experimental techniques such as Raman microscopy, atomic force microscopy, NMR spectroscopy, transmission electron microscopy, XAS, and the like can be carried out on materials-spent battery electrodes to better understand the phenomena that lead to degradation during use. These techniques provide diagnostic techniques that identify materials properties and materials interactions that limit lifetime, performance, and thermal stabiity. The accelerated rate calorimeter finds use in identifying safety-related situations that lead to thermal runaway and destruction of the battery. 

Non-adiabatic screening tests such as Carius tube111 and the Accelerating Rate Calorimeter (ARC ), corrected for sample heat losses due to thermal inertia, can also be used for screening. If it is known that the reaction is a vapour pressure system, DSC may be used. 

D I Townsend J C Tou, "Thermal Hazard Evaluation by an Accelerating Rate Calorimeter", Thermochimica Acta, 37, 1-30, 1980... 

Adiabatic conditions may be achieved either by a thermal insulation or by an active compensation of heat losses. Examples are the Dewar calorimeter, achieving a thermal insulation [2-4] or the Accelerating Rate Calorimeter (ARC) [5] or the Phitec [6], using a compensation heater avoiding the heat flow from the sample to the surroundings. These calorimeters are especially useful for the characterization of runaway reactions. 

The methods used for the isothermal reactor can also be used here, but must be completed by a thermal study over the total temperature range in which the reactor will be operated. Therefore, DSC in the scanning mode, or adiabatic calorimeters such as the Accelerating Rate Calorimeter or simply the Dewar flask, can be used. 

M.W. Whitmore and J.K. Wilberforce, Use of the Accelerating Rate Calorimeter and the Thermal Activity Monitor to Estimate Stability Temperatures, J. Loss Prev. Process Ind., 6-2, 95-101 (1993). 

---