The Accelerating Rate Calorimeter has been used extensively to study the stability of batteries and heat output from batteries under conditions of use and abuse. Much information is available: www.thtuk.com.

These applications have given insight into battery safety and have been used mainly in battery research. These tests can be time consuming and the instrument has a significant price tag. The RSD will not give quantitative data on such an array of test protocols, but can be applied to battery stability and safety. The RSD has advantages, it is more rapid in its operation, it is simpler to use and data analysis is more easily. In addition the RSD is a much lower cost instrument and it has broad versatility.

It is clear that there can be many applications of the RSD to battery safety studies. This is true especially where a fast turn round time is required. Here we report simply how the thermal stability of a Li-ion battery can be quantified in the RSD and how such testing can be extended. We also consider briefly what the potential use is for the RSD in the area of battery safety.

It should be noted that within the RSD the sample temperature should be measured within the sample. This is suitable for a chemical but not simple for a battery. To overcome this, in these tests the battery is enclosed within an insulating package. The RSD method utilises a temperature ramp or can be used isothermally. During a temperature ramp, when a sample is encased in insulation as here, the battery temperature will be well below that of the recirculating air calorimeter temperature. However, the battery is will still subject to the same temperature ramp.