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Summary: The battery thermal management system based on phase change materials (PCMs) has proven to be a safe, inexpensive, and high‐performance technology, which is currently gaining popularity over the other battery thermal management systems. PCMs are able to absorb heat generated by batteries, prolong battery life, and improve their performance. Organic compounds, such as paraffin, are widely used as phase change materials for the battery thermal management systems; however, there are no published data on the application of inorganic PCMs. Therefore, the main objective of this work is developing of two composite inorganic PCMs based on magnesium chloride hexahydrate and characterizing their properties for passive thermal control of lithium‐ion battery packs. Moreover, to have a valid baseline and compare the behavior of two inorganic PCMs with currently commercialized and well investigated organic PCM, paraffin wax was used as reference material for both mixtures. All three PCMs were impregnated into the expanded graphite matrix to enhance their thermal conductivity. The material characterization studies, including thermal properties investigation, density and viscosity measurements, soaking and compression testing, evaluation of thermal expansion, thermal conductivity, and micro X‐ray fluorescence analysis, were conducted for all PCMs. The results indicate that both inorganic mixtures are appropriate for thermal management of Li‐ion battery packs. Future work with the developed and characterized composite inorganic PCMs will include electrical cycling studies and nail penetration tests to reveal their effectiveness for passive thermal management of Li‐ion battery packs. [ABSTRACT FROM AUTHOR]

In this study, an inorganic mixture based on bischofite (industrial by-product) was developed and characterized for its application as a phase change material for low-temperature thermal energy storage. The most appropriate composition was established as 40 wt% bischofite and 60 wt% Mg(NO3)2 · 6H2O. Thermophysical properties were defined and compared with those of the mixture with synthetic MgCl2 · 6H2O. The heat of fusion and melting temperature were measured as 62.0°C and 132.5 kJ kg−1 for the mixture with MgCl2 · 6H2O and 58.2°C and 116.9 kJ kg−1 for the mixture with bischofite. The specific heat capacity values, cycling, and thermal stability for both mixtures were also determined. For the mixture with MgCl2 · 6H2O, the densities of the solid and liquid states were 1517 kg m−3 (ambient temperature) and 1515 kg m−3 (at 60-70°C), respectively. For the mixture with bischofite, the densities of the solid and liquid states were 1525 kg m−3 (ambient temperature) and 1535 kg m−3 (at 60-70°C), respectively. Both mixtures show supercooling of about 23.4 and 34.1°C for the mixture with bischofite and MgCl2 · 6H2O, respectively. In addition, it was shown that supercooling may be reduced by increasing the quantity of material tested. Thereby, it was established that an inorganic mixture based on bischofite is a promising PCM for low-temperature thermal energy storage applications. [ABSTRACT FROM AUTHOR]

Brines coming from salted lakes such as that at the Atacama desert in Chile produce by-products or wastes which today are stored in the nearby from the production areas. Bischofite is one of those by-products, and therefore, its composition may vary from batch to batch. Because bischofite has been identified as a good candidate to be used as phase change material (PCM) for latent heat thermal energy storage, the influence of the variation of bischofite composite with its main impurities in this potential used needs to be evaluated. The main impurities of bischofite are the cations sodium, potassium and lithium and the anions chloride and sulfate. The results of this investigation established that the presence of KCl and NaCl in bischofite (up to 5 wt%) does not affect its use as PCM, because its melting enthalpy and temperature do not vary significantly. It is interesting that small contents of LiCl in bischofite do not change significantly its melting enthalpy but decrease the melting temperature. Such change may enable the usage of this material as PCM in other applications at lower temperatures. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The literature shows that inorganic phase change materials (PCM) have been very seldom microencapsulated, so this study aims to contribute to filling this research gap. Bischofite, a by-product from the non-metallic industry identified as having good potential to be used as inorganic PCM, was microencapsulated by means of a fluidized bed method with acrylic as polymer and chloroform as solvent, after compatibility studies of both several solvents and several polymers. The formation of bischofite and pure MgCl2 · 6H2O microcapsules was investigated and analyzed. Results showed an efficiency in microencapsulation of 95% could be achieved when using 2 min of fluidization time and 2 kg/h of atomization flow. The final microcapsules had excellent melting temperatures and enthalpy compared to the original PCM, 104.6 °C and 95 J/g for bischofite, and 95.3 and 118.3 for MgCl2 · 6H2O. [ABSTRACT FROM AUTHOR]

Physical characterization and thermal properties of bischofite, a by-product from the non-metallic industry, were determined and compared with those to MgCl 2 ·6H 2 O with the idea of using it as phase change material in thermal energy storage applications. The melting point and heat of fusion were measured in the temperature range from 30 °C to 150 °C, where T fus and Δ H fus were 100 °C and 115 kJ/kg for bischofite, and 114.5 °C and 135 kJ/kg for MgCl 2 ·6H 2 O. The solid heat capacity was determined from 25 °C to 60 °C, being 2.1 kJ/(kg K) at 60 °C for both samples. The measurements of the liquid heat capacity of bischofite were done from 115 °C to 125 °C and the Cp showed linear increase from 1.71 kJ/(kg K) to 3.01 kJ/(kg K). The thermal stability test (30 heating/cooling cycles) of bischofite and MgCl 2 ·6H 2 O shows subcooling of about 37 K and 29 K, respectively. The solid and liquid densities were determined using the pycnometrically method; for bischofite, ρ solid decrease from 1686 (at 30 °C) to 1513 kg/m 3 (at 50 °C) and ρ liq was 1481 kg/m 3 (at 115 °C). Based on the thermophysical properties evaluated, the energy storage density was evaluated for both materials, being 170 J/cm 3 for bischofite and 192 J/cm 3 for MgCl 2 ·6H 2 O. This study established that bishofite is a promissory PCM with similar thermophysical characteristics to magnesium chloride hydrate, but with a lower cost. Nevertheless, further work is needed to overcome the two main problems found, subcooling and segregation of the material. [ABSTRACT FROM AUTHOR]