Solid-liquid phase change materials (PCMs) are attractive candidates for thermal energy storage and electronics cooling applications, but once all the PCMs have completely phase-changed and approximate their thermal storage limit, they will become the bottleneck for heat dissipation on the contrary and the electronics have to stop working. In this paper, a modularized thermal storage unit (MTSU) was proposed to overcome such fatal drawback. Once the PCMs reach their limit, the completely phase-changed MTSU will be replaced by a new one due to the modularization. Such online thermal charging and offline thermal discharging working characteristics enable the continuous working of electronics. The proposed MTSU is fabricated by encapsulating paraffin with epoxy resin, and the paraffin is thermally enhanced via copper or nickel foams. Theoretical and experimental validations reveal that the ETC is increased by 376% via copper foam with the porosity of 95.52%, and by 205% for nickel foam with the porosity of 95.61% due to the relatively lower skeleton thermal conductivity of nickel foam. The cycled test revealed that the proposed MTSU has good thermal stability. Compared with the conventional TSU, the proposed MTSU avoids the slow re-solidification process and exhibits potential for continuous thermal storage over long periods of time. The proposed MTSU is expected to be applied in the field of driving batteries and solar-thermal conversion system. (C) 2018 Published by Elsevier Ltd.