Abstract:

Phase change materials (PCMs) can release and absorb latent energy through the phase change process, which has many applications in the field of temperature control and heat storage such as building energy conservation, solar energy storage, textile and other daily aspects. Most PCMs have problems of low thermal conductivity and leakage, and thus encapsulation is necessary for shape-stable and heat transfer enhancement. At present, microencapsulation and porous encapsulation are commonly used due to microencapsulation can build a relatively isolated system to prevent leakage and has a large specific surface area. And encapsulation by porous support has high energy storage density and utilization efficiency. This paper reviewed the structural characteristics and applicable types of the two methods, introduced the specific preparation methods and research progress of the encapsulation technologies such as spray drying, in-situ polymerization, complex coacervation, sol-gel, direct impregnation, vacuum adsorption and in-situ assembly. Besides, the paper briefly described the characteristics and progress of nanofiber encapsulation and solid-solid PCMs encapsulation. Finally, the evaluation contents and methods of shape stabilized phase change energy storage materials (SSPCMs) were summarized. Different methods had advantages and disadvantages in reducing leakage rate, increasing stability and improving thermal conductivity and storage efficiency. The shape-stable improvement and enhanced heat transfer are still the development focus of future PCMs encapsulation. The cost economy, simple process, high energy storage density, suitable phase change temperature and environmentally friendly PCMs would have greater application prospects.

Key words: phase change materials, energy storage technology, encapsulation technology, microencapsulation, porous support, composites

摘要：

相变储能材料（PCMs）是指利用自身相变潜热的释放或吸收，实现温度控制和热量储存的一类材料，具有诸多应用场景，然而PCMs存在易泄漏和导热性差的问题，封装是实现定型和强化传热的有效途径，微胶囊封装和多孔载体封装是目前较为常用的封装方式。本文梳理了微胶囊和多孔载体封装两种封装方式的结构特点和适用种类，介绍了喷雾干燥法、原位聚合法、复凝聚法、溶液-凝胶法、直接浸渍法、真空吸附法和原位组装封装技术的具体制备方式及其研究进展，并简述了纳米纤维封装和固-固PCMs封装的特点和进展，最后概括了形状稳定相变储能材料（SSPCMs）的评价内容和评价方法。不同封装技术在降低泄漏率、增加稳定性、提高导热性能和储能效率方面各有优劣，定型和强化传热仍是未来相变储能封装的发展重点，成本经济、工艺简单、储能密度高、相变温度适宜、环境友好型PCMs将具有更大的应用前景。

关键词: 相变材料, 储能技术, 封装技术, 微胶囊, 多孔介质, 复合材料