Lithium-ion batteries are the most commonly used portable energy storage technology due to their relatively high specific energy and power but face thermal issues that raise safety concerns, particularly in automotive and aerospace applications. In these environments, there is zero tolerance for catastrophic failures such as fire or cell rupture, making thermal management a strict requirement to mitigate thermal runaway potential. The optimum configurations for such thermal management systems are dependent on both the thermo-electrochemical properties of the batteries and operating conditions/engineering constraints. The aim of this study is to determine the effect of various combined active (liquid heat exchanger) and passive (phase-change material) thermal management techniques on cell temperatures and thermal balancing. The cell configuration and volume/weight constraints have important roles in optimizing the thermal management technique, particularly when utilizing both active and passive systems together. A computational modeling study including conjugate heat transfer and fluid dynamics coupled with thermo-electrochemical dynamics is performed to investigate design trade-offs in lithium-ion battery thermal management strategies. It was found that phase-change material properties and cell spacing have a significant effect on the maximum and gradient of temperature in a module cooled by combined active and passive thermal management systems.