An experimental investigating on the effect of contact resistance for pouch-type lithium-ion batteries on the performance and safety

The lithium-ion battery is one of the most widely used secondary batteries in various fields because of its high energy density and good life characteristics. A battery system is designed in a serial-parallel combination for the appropriate energy and power performance required by the system. However, due to problems in the manufacturing process of the lithium-ion battery, the cell characteristics may be manufactured differently, which may lead to imbalance between battery cells. In particular, contact resistance inevitably occurs between the tab of the battery and the bus bar connected to the anode and the cathode of the battery. Such contact resistance is a factor that discharges the current applied to the battery and affects performance and safety. Therefore, research on the effect of the contact resistance is required, and this research analyzes a phenomenon that may occur when the contact resistance of the pouch type battery cell is different based on an experiment. As a result, it was confirmed that high temperature heat is generated at the connection part as well as instability of the current applied to the battery depending on the size of the contact resistance, which may affect performance and safety.