Experimental thermal and electrical evaluation of a compact PCB-based interconnect for Yuasa LIM50 lithium-ion modules

This study investigates the thermal and electrical performance of Yuasa LIM50 lithium-ion modules under a new printed circuit board (PCB)-based design modification. The modification replaces traditional wiring between 12 series-connected cells with a compact, high-current PCB interconnection using Würth connectors and integrated thermocouple sensing points. Experiments were conducted using original and PCB-mounted modules at 1 C, 2 C and 3 C c harge/discharge rates under natural convection. Results show no significant difference in electrical performance between configurations. Over matched discharge phases, the mean cell temperature rise was also practically the same: 13.2 °C (original) vs 13.0 °C (PCB) at 2 C, and 18.0 °C vs 18.4 °C at 3 C, and the energy lost per cycle agreed within 6%. An energy balance and step-resistance analysis show that interconnect Joule heating is a small fraction of total module heat generation, which explains why the interconnect design has little influence on cell temperature. The PCB-based design therefore matches the thermal and electrical performance of the original wiring while reducing wiring complexity and simplifying assembly, making it a promising approach for future battery pack design.