Shore Andrew, Roller John, Bergeson Jennifer, Hamadani Behrang H
National Institute of Standards and Technology, Gaithersburg, MD 20899 USA.
Energy Sci Eng. 2021 Nov;9(11). doi: 10.1002/ese3.964.
As interest in Internet-of-Things (IoT) devices like wireless sensors increases, research efforts have focused on finding ways for these sensors to self-harvest energy from the environment in which they are installed. Photovoltaic (PV) cells or mini-modules are an intuitive choice for harvesting indoor ambient light, even under low light conditions, and using it for battery charging and powering of these devices. Characterizations of battery charging, for small rechargeable batteries from low charge to full charge, have been investigated using PV mini-modules of equal area. We present battery charging results using three different PV technologies, monocrystalline silicon (c-Si), gallium-indium-phosphide (GaInP) and gallium-arsenide (GaAs) under a warm color temperature (3000 K) LED lighting at an illuminance of 1000 lx. Battery charging times are shortest for the more efficient GAInP and GaAs mini-modules whose spectral response are a better match to the LED test source, which contains mostly visible photons, and longest for the less efficient Si cells. As a demonstration, a wireless temperature sensor mote was attached to the charging circuit and operated to determine its power consumption in relation to the available charging power. The mote's maximum power draw was less than the charging power from the least efficient c-Si mini-module. Our findings affirm the feasibility of utilizing PV under typical indoor lighting conditions to power IoT devices.
随着对无线传感器等物联网（IoT）设备的兴趣增加，研究工作集中在寻找方法让这些传感器从其安装环境中自行收集能量。光伏（PV）电池或微型模块是收集室内环境光的直观选择，即使在低光照条件下，也能利用这些光为电池充电并为这些设备供电。使用面积相等的光伏微型模块，对小型可充电电池从低电量到充满电的电池充电特性进行了研究。我们展示了在色温为3000K、照度为1000勒克斯的暖色温LED照明下，使用三种不同的光伏技术——单晶硅（c-Si）、磷化镓铟（GaInP）和砷化镓（GaAs）的电池充电结果。对于光谱响应与主要包含可见光光子的LED测试源更匹配的效率更高的GaInP和GaAs微型模块，电池充电时间最短，而对于效率较低的硅电池，充电时间最长。作为演示，将一个无线温度传感器节点连接到充电电路，并运行以确定其与可用充电功率相关的功耗。该节点的最大功耗小于效率最低的c-Si微型模块的充电功率。我们的研究结果证实了在典型室内照明条件下利用光伏为物联网设备供电的可行性。
