With the development of mobile technology, people have higher and higher requirements for battery life, such as electronic devices such as AR/VR Often limited by limited battery capacity, even smart phones are charged at least once a day. In the past ten years, wearable devices have made great progress, but their power supply solutions mainly rely on small electrochemical energy storage devices, such as batteries, super capacitors, and so on. The disadvantage of this traditional power supply device is that the power and power density are limited, and the battery life is also limited.

In order to solve this problem, researchers try to reduce power consumption while increasing energy harvesting efficiency to improve battery life. At the same time, it began to explore the prospects of bio-batteries. Currently, bio-battery self-powered sensors can reduce power consumption, but they cannot provide enough power for measurement and data transmission tasks.

Recently, engineers at the University of California, San Diego developed a flexible wearable device that can convert sweat into electricity. This solution that relies on the human body for power supply can be applied to small electronic products such as VR and mobile phones in the future. It is reported that this is a thin and light device attached to the fingertips, and its size is only 2 square centimeters.

In a paper titled “Passive sweat-charged bio-battery: efficient energy conversion”, researchers Announced more details about this technology. It is reported that the solution contains a sweat-absorbing filler composed of foamed carbon electrodes. The filler contains special enzymes, which will cause a special chemical reaction between oxygen molecules and lactic acid after encountering sweat, which can generate about 400mj when you sleep. /cm of electricity is enough to power digital watches (non-smart watches) or electric displays equipped with a vitamin C detector.

The solution can convert sweat into a small amount of electricity, and it also contains a piezoelectric power generation chip that can The light pressure is transformed into another kind of energy. In other words, when you sleep, it can rely on your sweat to charge, and in daily life, typing, texting, pressing the mouse and other actions with your fingers can also power the wearable device.

Researchers said: Fingertips are one of the most sweaty parts of the human body, even if they are not working out, they will sweat . Generally, you may feel that other parts of your body sweat more easily than your fingers. This is because these parts are not well ventilated with your fingers, and your fingers are exposed to air for a long time, so sweat evaporates soon after secretion.

Scientists attach the sweat generating device to the abdomen of the finger to directly collect the sweat secreted by the finger. In detail, the solution includes a bioanode based on lactate oxidase and a cathode based on oxygen reduction reaction.

Compared with other technologies that use sweat to generate electricity, the device developed by UCSD does not require additional actions by the user to operate , And it's small and light enough. Its other features also include: thin, flexible, and does not interfere with your daily actions such as pulling the refrigerator door, holding a water bottle, and turning the steering wheel. If you use this device on all ten fingers, you can generate 10 times the power.

Lu Yin, a nanoengineering student at the UCSD Jacobs School of Engineering, said: Imagine if you run to generate electricity, it usually costs Hundreds of joules of energy are generated, and only a few millijoules of energy are generated. The efficiency of this energy conversion is very low. Currently, there is no solution that can save electricity without additional power. In contrast, the scheme of using sweat to generate electricity is much more efficient, and it can generate electricity even while sleeping. And it only takes half a millijoule of energy to press each finger pad.

However, at present, the power that can be generated by this program is limited and can only power digital watches. In the future, optimization may be able to provide smart Powered by mobile phone or VR headset.

In terms of application scenarios, researchers believe that it can continuously generate electricity through your touch in your daily life, such as brushing Cell phone, eating, typing, watching TV, etc.

Of course, it can also be used in scenes such as VR fitness, especially when you are playing "Beat Saber", "Supernatural" It will sweat a lot during the game, which will bring a lot of resources for sweat power generation. In fact, in addition to the game scene in recent years, VR fitness applications have also become popular. Facebook is optimistic about this application scene and even launched its own fitness exercise tracking application: "Oculus Move". Therefore, if sweat power generation and VR fitness are combined, the battery life and experience of VR headsets may be greatly improved in the future.

In addition, you can also press the VR handle to generate electricity. In addition to the fingertips, if the device is placed in the VR headset mask part, it may further enhance the power generation effect.

In short, with the development of technology, some research has been able to provide sensors and Electronic products are supplied with power intermittently or continuously, but the energy conversion efficiency of most solutions is not high enough, and it is inconvenient to use and lack practicality. In contrast, the advantage of the solution of relying on the sweat of the fingertips to supply power is that it can continuously supply power through passive sweating, does not rely on the external environment and does not require the user to exercise, and is convenient enough to use.