General Motors (GM) recently purchased an iso-BTC after extensive trials with their batteries samples, even though they have adiabatic calorimeters available to them. Here’s why.
Fires and explosions involving Li-ion batteries occur when heat is not removed effectively and leads to a rise in temperature. Thermal management systems are designed to prevent such incidents but can only do so if they are designed to handle the necessary heat load – which raises the question: how can this load be determined?
The answer is HEL’s iso-BTC, which works exactly like a thermal management system except it reports how much heat is being removed while connected to real battery samples. Many companies fail to appreciate the difference in data from an isothermal calorimeter and the more commonly used adiabatic type (such as HEL’s BTC-500 based on the “ARC” principle).
Typical results are plotted below where the heat load (power loss) is shown at three different discharge rates, for the same battery at the same (constant) temperature. The test can be repeated at different temperatures (for example between -40 to + 100C) to determine the effect of weather conditions
The HEL Group has prepared a FREE application note, which highlights key performance indicators of thermal control data based on isothermal calorimetry, which can be found here or copy and paste the link below in your browser.