Electrocaloric multilayer cooling device concepts

铁冷却利用电场驱动的熵变化在固态材料相变附近。它被认为是一种非常节能和环保的冷却技术。由于电能无处不在，特别是电热（EC）冷却效果似乎在未来的日常设备中具有最大的应用潜力。第一个资助期的理论研究清楚地表明，EC冷却装置的材料应该是松弛型的，它应该是化学计量组成的，致密和无孔，以施加高电场强度，它应该非常薄。松弛薄膜最能满足这些要求。因此，我们继续研究batio3基材料，这是一种环境友好的无铅材料，可以承受如此高的电场。特别是，（Ba,Sc,Ca）（Ti,Zr）O3:Mn和（Ba,Sc,Ca）（Ti,Sn）O3:Mn仍然是我们工作的重点，因为它们在很宽的温度范围内表现出很大的EC活性。我们采用多靶溅射的方法，分别控制每个靶的功率，从而很容易地调整薄膜的组成。此外，多目标溅射可以在刚性和柔性基材上进行大规模生产，也可以在卷对卷上沉积。特别是，第二个资助期的提案侧重于材料开发和优化，嵌入式电极多层堆叠的制造和评估，多层EC冷却装置的概念以及EC冷却示范装置的制造和评估。

Ferroic cooling exploits electric field-driven entropy changes near phase transitions in solid-state materials. It is considered an exceptionally energy-efficient and environmentally friendly cooling technology. Since electrical energy is ubiquitously available, in particular the electrocaloric (EC) cooling effect seems to have the highest potential for being used in future everyday devices.Theoretical studies in the first funding period have clearly shown that the material for EC cooling devices should make be of relaxor-type, that it should be composed stoichiometrically, dense and poreless to apply high electric field strengths and that it should be very thin. Relaxor thin films meet these requirements at the best.For that reason, we continue to study BaTiO3-based materials which are environmentally friendly lead-free materials allowing such high electric fields. In particular, (Ba,Sc,Ca)(Ti,Zr)O3:Mn and (Ba,Sc,Ca)(Ti,Sn)O3:Mn remain in the focus of our work because they show large EC activity in a broad temperature range. We adjust the composition of these thin films easily by multi-target sputtering where the power of each target is controlled separately. Furthermore, multi-target sputtering enables large-scale production on stiff and on flexible substrates as well as reel-to-reel deposition.In particular, the proposal for the second funding period focuses on material development and optimization, on fabrication and evaluation of multilayer stacks with embedded electrodes, on the concept of multilayer EC cooling devices and on the fabrication and evaluation of an EC cooling demonstrators.