Experimental Investigation of Thin PCM Packages and Thermal Spreader for Thermal Management of Portable Electronic Devices

Abstract

As the size of portable electronic devices, like tablet computers or smartphones, continues to decrease and their performance continues to increase, thermal management of the generated heat is becoming an ever more important issue. Phase change materials (PCMs) integration is a promising approach to reduce overheating of electronic components in tablet design while keeping the temperature of the cover surface within a comfortable range. This work focuses on the experimental thermal investigation of thin encapsulated PCM packages in combination with a thermal spreader as a solution for thermal management in portable electronic devices. The packages had an overall thickness of less than 2 mm in order to meet the requirements for integration in thin portable electronic devices. A simplified setup at a scale similar to a modern tablet computer was used for the experimental investigations. Experiments were conducted to study, for the first time, the local thermal behavior of the thin packages and their influence on the temperature increase of the heat source and cover surface. Two different PCMs were tested: n-eicosane and dodecanoic acid. An aluminum sheet with a thickness of 0.4 mm was used as a thermal spreader. It was determined that the combination of a spreader and the thin PCM packages led to substantial reduction of the temperature increase of both the heater and the cover. Compared to the case where neither a spreader nor a PCM package was used, the heater and cover maximum temperatures were reduced by 45% and 42%, respectively, when a constant heat power input of 5 W for 60 min was applied.

Experimental Evaluation of a Latent Heat Storage Module with a Heat Spreader for Thermal Management of a Tablet Computer

“…Note: All properties are from [16] except the density and thermal conductivity of n-eicosane in the liquid state, which are from [19].…”

“…The DC power supply for the polyimide heater (Statco Energy 3PN501B) could supply up to 30 V and was controlled via an analogue voltage signal produced by a National Instruments Compact DAQ system with an NI-9263 voltage output module. Using this system, the voltage to the heater could be controlled from a PC workstation [22]. The DC power supply for the polyimide heater (Statco Energy 3PN501B) could supply up to 30 V and was controlled via an analogue voltage signal produced by a National Instruments Compact DAQ system with an NI-9263 voltage output module.…”

“…The DC power supply for the polyimide heater (Statco Energy 3PN501B) could supply up to 30 V and was controlled via an analogue voltage signal produced by a National Instruments Compact DAQ system with an NI-9263 voltage output module. Using this system, the voltage to the heater could be controlled from a PC workstation [22].…”

“…It is important to note that it is not possible to estimate the PCM melting fraction in these experiments, as this would require many thermocouples in the PCM package as in Ahmed et al [5], or all over its surface as in the work of Maranda et al [16]. However, there is significant evidence that the LHTES module was storing heat and positively influencing the temperature control of the mock tablet computer when comparing the There was clear evidence of a phase change in this experiment: inflections were observed in the temperature profile inside the mock tablet (T in-1 and T in-2 ) and on the back surface (T B-1 ) (all indicated with red arrows), and to a lesser extent on the front surface (T F-1 ).…”

“…Only a few research groups around the world have published on work performed on thin LHTESs. Fundamental work on the use of thin LHTES modules for thermal management was carried out by Maranda et al (2019) [16]. Using a simplified setup, LHTES modules (100 mm × 100 mm × 2 mm) were experimentally tested.…”