一邊講話一邊發電 新手機再也不用充電池 | 環境資訊中心
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一邊講話一邊發電 新手機再也不用充電池

聲波轉換為能量 壓電體是關鍵

2008年12月09日
摘譯自2008年12月4日ENS美國,德州,卡城報導;江昱均編譯;蔡麗伶審校

未來新手機可邊講話邊發電美國德州農工大學(Texas A&M University)的一位科學家研發出一種新的、不需電池而能自行供電的手機,這種手機將使用者說話聲波轉換成動力,讓手機持續運轉。

專精於奈米科技的德州農工大學化工系的卡庚教授(Tahir Cagin)發現一種特殊材料,在極小尺寸下,這種材料能量轉換的效率能提升100%。

卡庚和在休士頓大學的合作夥伴都是在能量轉換新領域的先鋒。他們專注於研發不需替換電力供應元件而能自行供電的系統裝置。卡庚表示:「即便是僅僅以聲波形式產生的任何擾動,例如氣體、液體、或固體的壓力波動,都能夠被接收而啟動的奈米或微米裝置,在未來只要依照這樣的需求去處理和製造奈米和微米材料就可以達到。」

卡庚教授曾經因奈米科技而獲得費曼獎這項殊榮,他解釋這項手機聲波供電技術的關鍵是壓電體(piezoelectrics)。這個單字源自希臘文「piezein」,意指「壓力」。壓電體是像水晶或陶瓷等材料,當機械壓力施加其上時,能夠產生一定的電場。

卡庚與其團隊發現將某種特殊的壓電材料裁製成特定的尺寸大小──21奈米厚,就能夠將能量轉換的效率提升100%。他說如果這種材料裁製成其他的尺寸,無論是較大或小,在能量轉換效率上都沒有特定的21納米厚來的有效。

卡庚的發現刊登在美國物理學會的科學期刊《物理評論B》(Physical Review B),這一研究將對許多低功耗電器產生深遠的影響,像是手機、筆記型電腦和其他個人通訊系統,使用者可能是一般消費者,執法人員,甚至是戰場上的士兵。

法國科學家在1880年代發現壓電體,首先於第一次世界大戰時應用在聲納裝置中。現今在麥克風、石英錶和汽車點煙器中都可發現它的蹤跡。有些夜總會的地板也應用壓電材料,以吸收並轉換舞者跳舞時腳步所產生的壓力和能量,由此來供應夜總會中的照明。

壓電發電機也可以裝置在人行道或車道上,將機械動力轉換成電力。卡庚表示,雖然壓電體在各方面的應用與時並進,它在奈米領域上應用則是相對較新的發展,也有許多不同與複雜的層面必須進一步考量。

卡庚說道:「當材料縮小到奈米大小的應用,它們的物理性和反應都會有劇烈變化……壓電體就是一個例子。我們已經證實在20和23奈米之間,壓電體的電力轉換效能可以提升一倍。」他補充說:「我們研究物理學的基本自然法則,並且試著將此應用在發展更好的電機材料與提升這些材料的效能。」

對廣受歡迎、功能多樣的MP3播放器與手機而言,電池壽命非常重要。而除了有益於便利一般消費者使用之外,自行供電系統也引起國防部等聯邦單位的注意。

美國國防高級研究計劃署(Defense Advanced Research Project Agency)為戰場上的士兵開發出能接收行走產生的能量,並轉換而產生電能來供應他們的攜帶式裝備的各種裝置。而像是用於偵測爆裂物等之類的感應器將可應用這種自行供電科技,而不需受限於測試殘餘電量或更換電池等需求。

No Batteries Required: Self-powered Devices on the Horizon
COLLEGE STATION, Texas, December 4, 2008 (ENS)

A self-powering cell phone that converts the sound waves of the user's speech into the energy it needs to keep running - without a battery charge - is being made possible by the work of a scientist at Texas A&M University.

Tahir Cagin, a professor in the Department of Chemical Engineering at Texas A&M, is a nantechnology specialist who has discovered a type of material that can covert energy at a 100 percent increase when manufactured at a very small size.

Cagin and his partners from the University of Houston are pioneers in the new field of power harvesting.

They are developing self-powered devices that do not require replaceable power supplies.

"Even the disturbances in the form of sound waves such as pressure waves in gases, liquids and solids may be harvested for powering nano and micro devices of the future if these materials are processed and manufactured appropriately for this purpose," Cagin said.

Key to this technology are piezoelectrics, explained Cagin, who is a past recipient of the prestigious Feynman Prize in Nanotechnology.

Derived from the Greek word "piezein," which means "to press," piezoelectrics are materials, such as crystals or ceramics, that generate voltage when a form of mechanical pressure is applied.

Cagin and his team have found that a certain type of piezoelectric material can covert energy at a 100 percent increase when manufactured at a specific size - 21 nanometers in thickness.

When the materials are constructed larger or smaller than this specific size they show a significant decrease in their energy-converting capacity, he said.

Cagin's findings, which are detailed in an article published this fall in "Physical Review B," the scientific journal of the American Physical Society, could have profound effects for low-powered electronic devices such as cell phones, laptops, and personal communicators used by everyone from the average consumer to law enforcement officers and to soldiers on the battlefield.

Discovered by French scientists in the 1880s, piezoelectrics were first used in sonar devices during World War I. Today they are found in microphones, quartz watches, and cigarette lighters in automobiles.

Some night clubs feature dance floors built with piezoelectrics that absorb and convert the energy from footsteps in order to help power lights in the club.

Piezoelectric generators can be placed on sidewalks or in car lanes to transform the mechanical power to electrical power.

While advances in those applications are progressing, piezoelectric work at the nanoscale is a relatively new endeavor with different and complex aspects to consider, said Cagin.

"When materials are brought down to the nanoscale dimension, their properties for some performance characteristics dramatically change," said Cagin.

"One such example is with piezoelectric materials," he said. "We have demonstrated that when you go to a particular length scale - between 20 and 23 nanometers - you actually improve the energy-harvesting capacity by 100 percent."

"We're studying basic laws of nature such as physics and we're trying to apply that in terms of developing better engineering materials, better performing engineering materials. "

Battery life is a major concern for popular mp3 players and cell phones that are required to perform an ever-expanding range of functions. But beyond consumer convenience, self-powering devices are of interest to federal agencies such as the Defense Department.

The Defense Advanced Research Projects Agency has investigated ways for soldiers in the field to generate power for their portable equipment through the energy harvested from walking. And sensors, such as those used to detect explosives, could utilize a self-powering technology that would eliminate the need for the testing and replacement of batteries.

作者

蔡麗伶(LiLing Barricman)

In my healing journey and learning to attain the breath awareness, I become aware of the reality that all the creatures of the world are breathing the same breath. Take action, here and now. From my physical being to the every corner of this out of balance's planet.