Electrical Analysis about internal short circuit using additional resistance in high energy lithium-ion battery

Safety is critical issue for using lithium-ion battery. There are many causes and effects of faults in lithium-ion battery. Thermal runaway is the most hazardous safety problem. It leads to the dangerous result such as fire or explosion of the battery. If thermal runaway is occurred in application, its application like electrical vehicle or energy storage system would be a catastrophe. For preventing thermal runaway, diagnosis and prognosis of main causes are significant. One of the main causes of thermal runaway is internal short circuit. In this work, change of voltage and temperature from internal short circuit are analyzed. Usually, it is hard to detect internal short circuit in normal electrical equivalent circuit model (EECM). Thus, lots of papers apply a parallel resistor in EECM to catch internal short circuit. In this paper, this model is used to show effects from internal short circuit. Resistance of parallel resistor represents the probability of occurrence of internal short circuit. Current passing through the parallel resistor indicates the leakage current inside of the battery which is not detected. To verify the model in high energy lithium-ion battery, induced internal short circuit suggested in UL standard is conducted. And change of voltage, internal leakage current, parallel resistor's value is analyzed.