基于聚合物纳米复合材料驻极体的微型驻极体发电机

Micro electret generators have an good potential to harvest motion energy from surrounding environment. But the existing micro electret generators failed far to reach expected power output. This project will develop a high-performance micro electret generator based on polymer nanocomposites for power supply for wearable devices. The research content includes: Investigating the preparation method of high-performance electret and the charging enhancement method; Analyzing the charging stability of the electret; Theoretically modeling the electret generator; Analyzing the effect of parasitic capacitance on power output of the generator; Investigating methods of design, fabrication and output extraction of the electret generator. The innovative points include: Combining SiO2 nanoparticles which have a potential of high charge density and polymer with good charge stability to prepare high-performance nanocomposite electret, at the same time using laminated multilayers of charged electret films to increase the total charge quantity and stability; Novel electret generator without electrodes under electrets, whose charges will be all used to induce effective charges in the working electrodes to generate power output; New theoretical model of the electret generator without electrodes under electret, which includes parasitic capacitance; Using porous polymer with low dielectric constant as the electrode substrate to reduce parasitic capacitance, at the same time, to adjust the parasitic capacitance by adjusting porosity; Referencing the design idea of permanent magnet motors, the electret generator will have a symmetrical structure to make that the longitudinal electrostatic attractive forces between the electrets and the electrodes having induced charges counteract each other, and the mode of three-phase will be adopt to improve the smoothness of rectifier output voltage and the conversion efficiency.

微驻极体发电机是很有潜力的拾取环境动能的技术，但已有发电机远未达期待的输出。本项目面向可穿戴设备，研制聚合物纳米复合材料高性能微型驻极体发电机。研究内容包括：高性能驻极体制备和荷电增强方法及荷电稳定性，驻极体发电机理论建模，寄生电容对发电输出特性影响，发电机设计及加工方法，发电机输出提取方法。创新点包括：提出利用荷电密度高的SiO2纳米颗粒与荷电稳定性好的聚合物结合制备纳米复合材料驻极体，同时利用多层微米级驻极体薄膜叠层，提高驻极体总荷电量和稳定性；提出无驻极体基底电极驻极体发电机，驻极体电荷都用于诱导工作电极可输出有效电荷；提出包含寄生电容的无驻极体基底电极发电机理论模型；利用低介电常数多孔聚合物作为电极衬底，降低寄生电容的同时，通过调节孔隙率调节寄生电容；借鉴永磁电机设计思想，采用对称结构使驻极体与电极诱导电荷间纵向静电吸引力互相抵消，同时采用三相模式提高整流输出电压稳定性和转换效率。

随着物联网/传感网的迅速发展以及可穿戴设备的兴起，随处有大量耗能不高的电子器件，其能源供给主要依靠电池，而电池需定期置换或充电，给物联网/传感网及可穿戴设备的普遍应用带来很大不便。本项目面向物联网/传感网器节点、可穿戴设备的持续供电，研制拾取环境及人体运动动能的微型驻极体发电机，开展了无基底电极微型驻极体发电机的理论建模、优化设计方法研究，研究了寄生电容对驻极体发电机输出特性的影响；开展了微纳米结构化驻极体及电极衬底的制备方法研究，以及驻极体荷电方法、荷电增强方法及荷电稳定性研究；进行了驻极体发电机设计及加工制作方法研究，以及驻极体发电机输出提取和性能测试方法研究，设计制作了多种驻极体发电机，并对其输出特性等进行了测试。.本项目的理论研究为无衬底电驻极体发电机特性评估和优化设计提供了清晰、便捷的工具，使发电机得到很好的优化，输出性能得到极大的提高；研制的旋转式发电机转速1000rpm时输出功率大18.3mW，在0.8m/s的低风速下能够启动工作，低至0.6m/s风速下仍能驱动温湿度计工作，能够满足常规物联网/传感器节点供电功率需求；利用双极性图形化荷电驻极体和微纳孔聚合物衬底材料，使发电机输出功率进一步提高了5.3倍，基于该方法研制的面向可穿戴设备供电的驻极体发电机，佩戴于手腕上走路时，输出功率达到百微瓦，基本能满足小功率可穿戴设备的供电要求；研制的面向电源管理的同步开关发电机，实现了高效的电源管理，电能存储效率达68%。. 本项目所研制的微型驻极体发电机主体为聚合物材料，材料及加工制作成本低，制作工艺适合批量生产，本项目的研究成果为面驻极体发电机走向应用奠定了理论和技术基础，微型驻极体发电机在物联网/传感网节点、可穿戴设备供能以及自供能传感器方面将有广阔的应用前景。