Development of high-performance Li batteries with autonomic thermal regulation of their performance by encapsulated nanosized phase change materi

相变材料（PCMs）是一组有效的材料用于热管理，而不需要外部热调节系统。当由于环境温度的变化而发生相变时，pcm利用潜热来储存和释放热能。pcm先前已应用于建筑材料和一些电子产品，以在运行期间保持温度，并广泛应用于太阳能领域。在这个项目中，无机盐水合物（AxBy.n(H2O)）和低熔点的金属将被用作固液pcm，以自动调节锂离子电池的内部温度。目前，外部冷却系统用于防止锂离子电池达到危险温度（60摄氏度以上），防止热失控。在外部冷却系统中使用pcm以维持25到30摄氏度的工作温度的尝试有限，这对于锂离子电池来说是最佳的。无机pcm每单位体积的储热能力翻了一倍，与有机对应部件相比也更便宜；使他们成为理想的调查对象。当盐水合物发生相变，失去部分或全部水分时，潜热被吸收。当盐水合物再结晶时，潜热就会释放出来。使用无机pcm存在以下问题：相变时体积变化、导热性差、过冷性和腐蚀性。添加剂，如成核剂可以用来减少过冷。对于其他缺点，可以应用封装方法。封装可以有效地保护PCM和容器免受泄漏，并具有额外的功能，例如增加外壳的导热性。纳米核壳pcm具有更大的表面体积比，因此传热效率极高。该项目的目的是使用纳米级封装的核心外壳无机pcm来维持锂离子电池的内部温度。封装的pcm将直接插入电池中以保持热量。该项目的目标是使用封装的pcm来调节电池内部温度在25-30摄氏度之间，以优化性能。如果成功的话，封装的pcm有望减少对外部冷却系统的需求，而外部冷却系统会给当前的电池系统增加额外的质量和压力，从而提高效率。

Phase change materials (PCMs) are an efficient group of materials for use in thermal management without the need for an external thermal regulation system. PCMs take advantage of latent heat to store and release thermal energy when a phase change occurs due to a change in temperature to the surroundings. PCMs have been previously applied to building materials and some electronics to sustain temperatures during operation as well as extensive use in the solar energy sector. In this project, inorganic salt hydrates (AxBy.n(H2O)) and metals with low melting points will be used as solid-liquid PCMs to automatically regulate the internal temperature of a lithium-ion battery. Currently, external cooling systems are used to prevent lithium ion batteries from reaching dangerous temperature (above 60C) preventing thermal runaway. There have been limited attempts to use PCMs in external cooling systems to sustain working temperatures between 25 and 30C which would be optimal for Li-ion batteries.Inorganic PCMs have double the heat storage capacity per unit volume and are also cheaper in comparison to their organic counter parts; making them an ideal candidate for investigation. Latent heat is absorbed when the salt hydrates undergo a phase change losing part or all of their waters. Latent heat is then released when the salt hydrate is recrystalised. There are issues with using inorganic PCMs: change of volume during phase change, poor thermal conductivity, supercooling and corrosive properties. Additives, such as nucleating agents can be used to reduce supercooling. For the other draw backs, encapsulation methods can be applied. Encapsulation can be useful to protect the PCM and the container from leaking as well as additional functionality, such as increased thermal conductivity, being applied to the shell. Nanosized core shell PCMs have a greater surface to volume ratio and so are extremely efficient for heat transfer.The aim of this project is to use nanosized encapsulated core shell inorganic PCMs to maintain the internal temperature of a lithium ion battery. The encapsulated PCMs will be inserted directly into the battery to maintain heat. The objective of the project would be to use encapsulated PCMs to regulate the internal temperature of a battery between 25-30C to optimise performance. If successful, it is hoped the encapsulated PCMs would reduce the need for external cooling systems that add additional mass and strain to current battery systems making them more efficient.