Lebeda Flora, Demleitner Martin, Pongratz Annalena, Ruckdäschel Holger, Retsch Markus
Department of Chemistry, Physical Chemistry I, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany.
Bavarian Center for Battery Technology (BayBatt), Weiherstraße 26, 95448 Bayreuth, Germany.
ACS Omega. 2024 Sep 4;9(37):39232-39241. doi: 10.1021/acsomega.4c06558. eCollection 2024 Sep 17.
With the ongoing electrification of vehicles, thermal management is on everyone's lips. To prevent overheating in electronic systems, new design strategies for thermal dissipation are needed. Thermally anisotropic materials enable targeted directional heat transport due to their anisotropic thermal conduction. Laminates made of unidirectionally aligned carbon fibers in a polymer matrix can be tailored regarding their in-plane anisotropy. Exposing the laminates to a temperature gradient reveals that the thermal transport is determined by their anisotropic properties. The corresponding heat flow can be visualized by IR thermography. The combination of anisotropic laminate discs into composite materials, similar to building with toy bricks, enables precise control of heat transport in the macroscopic composite materials. Thus, we achieve control of heat flow at the level of the individual components. In addition, we show that the orientation of anisotropy relative to the temperature gradient is crucial to guide the heat flow selectively. We found that the ratio of thermal anisotropy, the amount and arrangement of anisotropic components, and their positioning in the composite strongly influence heat transport. By combining all these factors, we are able to locally control the heat flow in composites by creating materials to either dissipate heat or block heat transport. The proposed concept can be extended to different shapes of building blocks in two or three dimensions.
随着车辆的持续电气化，热管理成为了大家热议的话题。为防止电子系统过热，需要新的散热设计策略。热各向异性材料因其各向异性的热传导特性，能够实现有针对性的定向热传输。由聚合物基体中单向排列的碳纤维制成的层压板，其面内各向异性可进行定制。将层压板置于温度梯度下，结果表明热传输由其各向异性特性决定。相应的热流可用红外热成像法可视化。将各向异性层压盘组合成复合材料，类似于用积木搭建，能够精确控制宏观复合材料中的热传输。这样，我们就能在单个组件层面实现对热流的控制。此外，我们还表明，各向异性相对于温度梯度的方向对于选择性引导热流至关重要。我们发现，热各向异性的比率、各向异性组件的数量和排列方式以及它们在复合材料中的位置，都会对热传输产生强烈影响。通过综合考虑所有这些因素，我们能够通过制造散热或阻碍热传输的材料，在复合材料中局部控制热流。所提出的概念可以扩展到二维或三维的不同形状的积木。
