In this study, a battery case was developed using a 3D (three dimensional)-printed composite of hexagonal boron nitride (hBN) and polylactic acid (PLA) to enhance the thermal performance of lithium-ion battery (LiB) modules. A 10 wt.% amount of hBN was incorporated into the PLA matrix to improve the composite’s thermal conductivity while maintaining electrical insulation. A 3S2P (3 series and 2 parallel) battery configuration was initially evaluated based on the results of a baseline study for comparison and subsequently subjected to a newly developed test procedure to assess the thermal behavior of the designed case under identical environmental conditions. Initially, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were utilized for material characterization, and their results verified the successful integration of hBN by confirming its presence in the hBN-PLA composite. In thermal tests, experimental results revealed that the fabricated hBN-PLA composite battery case significantly enhanced heat conduction and reduced surface temperature gradients compared to the previous baseline study with no case. Specifically, the maximum cell temperature (T_max) decreased from 48.54 °C to 45.84 °C, and the temperature difference (ΔT) between the hottest and coldest cells was reduced from 4.65 °C to 3.75 °C, corresponding to an improvement of approximately 20%. A 3S2P LiB module was also tested under identical environmental conditions using a multi-cycle charge–discharge procedure designed to replicate real electric vehicle (EV) operation. Each cycle consisted of sequential low and high discharge zones with gradually increased current values from 2 A to 14 A followed by controlled charging and rest intervals. During the experimental procedure, the average ΔT between the cells was recorded as 2.38 °C, with a maximum value of 3.50 °C. These results collectively demonstrate that the 3D-printed hBN-PLA composite provides an effective and lightweight passive cooling solution for improving the thermal stability and safety of LiB modules in EV applications.

Temperature control has a crucial effect on the efficiency, safety, and lifetime of lithium-ion batteries (LiBs). For this reason, developing effective cooling solutions remains an active area of battery thermal management research. In this study, a honeycomb-shaped (HC-S) liquid cooling plate (LCP) was designed and manufactured for the thermal management of a pouch-type LiB. Although biomimetic and HC-S cooling structures have been investigated in battery thermal management studies, experimental evaluations of honeycomb-inspired LCPs for pouch-type LiBs with different coolant media are still limited. Therefore, this study contributes to the literature by experimentally assessing HC-S LCP and directly comparing various coolant circulation under the same discharge condition. The LCP was produced from Aluminum 6061-T6 using Computer Numerical Control (CNC) machining and experimentally tested under a constant 1C discharge rate. Pure water and a 50% pure water-50% monoethylene glycol (MEG)-based coolant mixture were circulated through the plate to evaluate their cooling performance. Among the tested cooling scenarios, the best thermal performance was obtained with 100% pure water circulation. In this case, the maximum temperature (Tmax) on the battery surface decreased from 42.595 °C to 28.939 °C, corresponding to a 32.06% reduction compared with the uncooled condition. The average temperature (Tavg) on surface was also reduced by 29.12%, from 38.935 °C to 27.598 °C. In addition, pure water circulation improved temperature uniformity by lowering the maximum temperature difference (∆Tmax) on the battery surface to approximately 2 °C. The results show that the proposed HC-S LCP can effectively maintain the battery temperature within the optimum operating range of 15-35 °C and improve the thermal safety of LiB.