This thesis investigates phase‑change‑material‑based passive thermal management for lithium‑ion battery modules in non‑road mobile machines. Two 2S2P modules of 14 Ah prismatic cells were assembled: a reference module without PCM and an otherwise identical module with a paraffin‑based PCM layer between the cells. After initial capacity, OCV and impedance characterisation, both modules were cycled at 1C and 1.5C using a constant‑current / constant‑voltage protocol, and the PCM module was additionally tested under a non‑road transient cycle (NRTC) combining 2C discharge with 1.5C recharge. At 1C, the modules showed similar thermal behaviour, with peak temperatures around 33-
34 °C and small temperature gradients, indicating limited benefit from PCM at moderate C‑rates. At 1.5C, the non‑PCM module reached about 37 °C with sensor‑to‑sensor differences near 5 °C, while the PCM module stayed below roughly 35 °C with gradients of about 3 °C. During 20 NRTC cycles, the PCM module maintained peak temperatures below approximately 34 °C and middle–edge differences of 3-4 °C without temperature
accumulation.
Overall, the results show that PCM‑based passive thermal management effectively suppresses hot spots and reduces temperature non‑uniformity under high‑rate and transient operation, while offering little advantage at lower C‑rates. Future work should extend NRTC
cycling to both PCM and non‑PCM modules over longer periods to link the observed thermal improvements to degradation behaviour and lifetime