“可穿戴的微电网”使用人体来为小型小工具提供电源

The technology draws inspiration from community microgrids. "We're applying the concept of the microgrid to createwearablesystems that are powered sustainably, reliably and independently," said co-first author Lu Yin, a nanoengineering Ph.D. student at the UC San Diego Jacobs School of Engineering. "Just like a city microgrid integrates a variety of local, renewable power sources like wind and solar, a wearable microgrid integratesdevicesthat locally harvest energy from different parts of the body, like sweat and movement, while containing energy storage."

The wearable microgrid is built from a combination of flexible electronic parts that were developed by the Nanobioelectronics team of UC San Diego nanoengineering professor Joseph Wang, who is the director of the Center forWearable Sensorsat UC San Diego and corresponding author on the current study. Each part is screen printed onto a shirt and placed in a way that optimizes the amount of energy collected.

可穿戴的MicroGrid使用来自人类汗水和运动的能量来为LCD手表和电致变色装置供电。

Source: Lu Yin

Biofuel cells that harvest energy from sweat are located inside the shirt at the chest. Devices that convert energy from movement into electricity, called摩擦电发电机,re positioned outside the shirt on the forearms and sides of the torso near the waist. They harvest energy from the swinging movement of the arms against the torso while walking or running. Supercapacitors outside the shirt on the chest temporarily store energy from both devices and then discharge it to power small electronics.

从运动和汗水中收获能量使可穿戴的微电网能够快速且连续地为可穿戴的微电网电动设备。摩擦发电机一旦用户开始移动，就立即提供电量，然后突破汗水。一旦用户开始出汗，生物燃料电池就开始提供电源并继续执行，并且在用户停止移动之后继续这样做。

"When you add these two together, they make up for each other's shortcomings," Yin said. "They are complementary and synergistic to enable fast startup and continuous power." The entire system boots two times faster than having just the biofuel cells alone, and lasts three times longer than the triboelectric generators alone.

在30分钟的会话期间，可穿戴微电网在受试者上进行测试，该课程由骑自行车机或跑步的10分钟组成，然后休息20分钟。该系统能够为LCD手表或小型电致变色显示器供电 - 一个设备，其在每个30分钟的会议中响应响应施加的电压而改变颜色。

Greater than the sum of its parts

The biofuel cells are equipped with enzymes that trigger a swapping of electrons between lactate and oxygen molecules in human sweat to generate electricity. Wang's team first reported these sweat-harvesting wearables in a paper published in 2013. Working with colleagues at the UC San Diego Center for Wearable Sensors, they later updated the technology to be stretchable and powerful enough to run small electronics.

The triboelectric generators are made of a negatively chargedmaterial, placed on the forearms, and a positively charged material, placed on the sides of the torso. As the arms swing against the torso while walking or running, the oppositely charged materials rub against each and generate electricity.

每个可穿戴的都提供不同类型的功率。生物燃料电池提供连续的低电压，而摩擦发电机提供高电压的脉冲。为了使系统到电力设备，需要将这些不同的电压组合并调节到一个稳定的电压中。这就是超级电容器进来的地方;它们充当水库，暂时将能量从两个电源储存，并且可以根据需要放电。

摩擦发电机收获从运动中的能量。

Source: Lu Yin

Yin compared the setup to a water supply system. "Imagine the biofuel cells are like a slow flowing faucet and the triboelectric generators are like a hose that shoots out jets of water," he said. "The超级电容器是他们都流入水箱,可以吗draw from that tank however you need to."

所有部件都与柔性银互连连接，也可以在衬衫上印刷并通过防水涂层绝缘。每个部分的性能不受重复弯曲，折叠和皱折的影响，或在水中洗涤 - 只要使用洗涤剂即可。

The main innovation of this work is not the wearable devices themselves, Yin said, but the systematic and efficient integration of all the devices. "We're not just adding A and B together and calling it a system. We chose parts that all have compatible form factors (everything here is printable, flexible and stretchable); matching performance; and complementary functionality, meaning they are all useful for the same scenario (in this case, rigorous movement)," he said.

其他应用程序

这种特殊系统对于体育运动和其他用户正在锻炼的情况有用。但这只是如何使用可穿戴微电网的一个示例。“我们并不将自己限制在这种设计上。我们可以通过选择不同类型的不同情景的能量收割机来调整系统，”尹说。

研究人员正在研究可以在用户内部坐在办公室内部的其他设计，例如或在外面缓慢移动。

The research was published inNature Communications.