Xinlong Dong,Binghe Zheng,Guoqing Zhang,Changren Xiao,Xiaoqing Yang
Phase change material (PCM) shows great potentials in battery thermal management (BTM) application, but there are significant challenges including PCM leakage, low secondary heat dissipation capability, and poor reprocessability. Herein, a type of phase change polymer (PCP) with intrinsic antileakage, reprocessability and heat dissipation capability is prepared via the copolymerization of octadecyl acrylate (OA) and methyl methacrylate (MMA). The rigid segment of MMA guarantees the shape stability of the PCP while avoiding using the crosslinkers, and thus simultaneously endows the linear PCP with quasi-thermoplastic property for reprocessing. The chemical-bonded phase changeable side chains from the OA segments provide a large latent heat of 100.5 J g –1 and fundamentally overcome the leakage problem. Additionally, the obtained PCP demonstrates a higher crystalline temperature favorable for secondary dissipation of the absorbed heat to the environment. Consequently, the obtained PCP demonstrates superior cooling performances in BTM applications. The temperature of the battery module with PCP cooling can be stably controlled below 52.5 °C under a harsh working environment of 3C-3C charge–discharge at 35 °C for 15 cycles. In contrast, the battery module adopting classical physically blended PCM cooling shows a much higher and gradually increasing maximum temperature during the cycles.
Li Zhang,Wenbin Yang,Zhuoni Jiang,Fangfang He,Kai Zhang,Jinghui Fan,Juying Wu
Novel microencapsulated phase change materials (MEPCMs) with high encapsulation capacity and enhanced leakage-prevention performance were prepared by in situ polymerization. For these MEPCMs, paraffin and melamine-formaldehyde resin (MF) are respectively used as core and shell, and graphene oxide (GO) nanosheets, which can be seen as extra protective screen, are situated at the interface between the core and the shell. Effects of GO on morphology, microstructure and properties of MEPCMs were characterized by scanning electronic microscopy (SEM), laser diffraction particle analyzer, atomic force microscopy (AFM), Fourier transformation infrared spectroscopy (FTIR), X-ray diffractometry (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and paraffin leakage rate test. The results show that the fabricated MEPCMs with GO nanosheets have gradual increasing average diameters from 6.32 to 15.89 μm with an increase content of GO, while the size of MEPCMs without GO is 5.63 μm. When the time of leakage rate test is 50 h, the MEPCMs prepared with 0.5 mg/mL GO aqueous dispersion have considerably high encapsulation ratio of 93.9 wt.%, and the leakage rate is reduced by 93.1% compared with those without GO. The high encapsulation capacity and enhanced leakage-prevention performance might be highly attractive for the application of MEPCMs.
Xiaoyin Cao,Lijuan Yang,Jia Zhang,Zhaoqi Zhu,Jiyan Li,Hanxue Sun,Weidong Liang,An Li
The fabrication of composite phase change materials (CPCMs) is significant for harvesting and converting solar energy. Hence, we first report novel CPCMs based on inorganic multi-shelled hollow spheres (MHS) via a facile hydrothermal method and calcination treatment. 1-Hexadecylamine (HDA) and Octadecylamine (ODA) were incorporated into MHS by a simple impregnation treatment to prepare CPCMs. Owing to its multi-shelled structure, the CPCMs have an outstanding ability of leakage resistance . In addition, the CPCMs themselves exhibit excellent solar absorption of up to 80 % without further surface modification. The thermal conductivity of the CPCMs containing HDA and ODA was increased by 1.03 times and 1.67 times by comparison with that of pure PCMs. The enthalpy of the as-resulted CPCMs is 207.6 J/g and 151.5 J/g, which is higher than most existing CPCMs, and the enthalpy of the CPCMs containing HDA and ODA after 100 times cycles can still attain 110.9 J/g and 104.7 J/g. Under 1sun irradiation, the light-to-thermal conversion efficiency of the CPCMs containing HDA and ODA was measured to be 90.0 % and 92.1 %, respectively. Taking advantage of its inherently physicochemical stability, superior light absorption and thermal conductivity and leakage resistance , scalable and cost-efficient fabrication process, such MHS-based CPCMs may have great potential for a wide variety of applications such as photothermal conversion, solar energy harvesting and storage, and so on.
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