Scientists create a generator on your wrist

Battery — trouble of wearable electronics. Rare the smartphone will be able to stretch without recharging the whole day if they at least sometimes use as directed. In search of a reliable power source for wearable devices, a group of Korean researchers drew attention to human body heat. Professor Ben Jin Cho (Byung Jin Cho) from Korean advanced Institute of science and technology (Korea Advanced Institute of Science and Technology, KAIST) and his colleagues have presented a wearable energy source using thermoelectric effect. According to the researchers, their flexible thermoelectric power generator can be an effective way to maintain the health of the wearable device for a long period of time. The team has developed a thermocouple in the form of a strip, which produces electricity from the heat of the human body.

The user requirements for wearable electronics is well known. It should be light, flexible and equipped with robust and durable power source. So far in this role was assigned to the battery, but the Korean researchers believe that you can forget about them if you use their device. Thermoelectric generators that minimise useless loss of heat is not new, as evidenced by videojustice to the article. As noted in the release, KAIST, today there are two varieties of them.

Organic thermogenerators built on flexible polymers, and is well aligned with the surface of human skin. As energy sources for wearable devices, the polymers would be perfect, if not for their low power output. In contrast to polymers, thermoelectric generators based on inorganic base able to produce enough energy, but they are heavy and bulky.

The KAIST team managed to combine the incompatible. Their thermocouple on a glass base easy and effective at the same time. As explained by Professor Cho: "Fiberglass is the top and bottom of the thermoelectric generator, keeping the inorganic material in the middle. This is a revolutionary approach to design. We were able to significantly reduce the weight of the (approximately 0.13 g/cm2), which is an important factor for wearable electronics."

A new thermoelectric generator can be bent repeatedly. After 120 of flexion, he still keeps high performance. The allowable bending radius of 20 mm. For generator the researchers developed two types of jelly-like pastes of n-type on the basis of bismuth telluride Bi2Te3 and p-type on the basis of antimony telluride Sb2Te3 and caused the paste to the fiberglass. Soaking the mesh, it forms a film of thermoelectric material of a thickness of several hundred microns. The power density of a new flexible thermoelectric generator is ten times higher than the known analogues. With dimensions of 10x10 cm, it is able to produce electricity with a capacity of 40 mW when the temperature difference between the ambient and body around 31oF (approximately 17oC).



Source: facepla.net