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Donald Sadoway 談可再生能源缺少的環節

Donald Sadoway: The missing link to renewable energy

 

Photo of three lions hunting on the Serengeti.

講者:Donald Sadoway

2012年3月演講,2012年3月在TED 2012上線

 

翻譯:洪曉慧

編輯:朱學恆

簡繁轉換:洪曉慧

後製:洪曉慧

字幕影片後制:謝旻均

 

影片請按此下載

MAC及手持裝置版本請按此下載

閱讀中文字幕純文字版本

 

關於這場演講

使用替代能源-如太陽能和風力-的關鍵是什麼?能源的儲存-這麼一來,即使在沒有太陽、無風時,我們的能源供應依舊不虞匱乏。在這場淺顯易懂、鼓舞人心的演講中,Donald Sadoway在黑板上為我們展示了未來用以儲存可再生能源的大型電池。正如他所言:「我們必須以不同的觀點思考問題。我們必須思考容量大且便宜的裝置。」

 

關於Donald Sadoway

Donald Sadoway致力於研究一種神奇電池-廉價、不可思議的高效能、使用「液態金屬」的三層電池。

 

為什麼要聽他演講

許多可再生能源系統的核心問題是:如何儲存能源,使它隨時隨地都能被傳輸到電網中,無論白天黑夜,甚至在無風或沒有太陽時?麻省理工學院的Donald Sadoway致力於研究電網規模的電池系統,使用三層液態金屬核心來儲存能源。藉由如比爾.蓋茨等人的資助,Sadoway和他兩位學生已成立液態金屬電池公司(LMBC),使這種電池上市。

 

「我們如何解決重要問題?提出正確問題。」

-Donald Sadoway

 

Donald Sadoway的英語網上資料

Home: Group Sadoway

Home: Liquid Metal Battery Corporation

 

[TED科技‧娛樂‧設計]

已有中譯字幕的TED影片目錄(繁體)(簡體)。請注意繁簡目錄是不一樣的。

 

Donald Sadoway 談可再生能源缺少的環節

 

供應這間演講廳燈光的電力僅產生於不久之前,因為依目前情況來看,電力需求與電力供應必須持續達成平衡。如果我從講台上走下,這段時間當中,有幾十兆瓦的風力發電停止輸入電網,這個不足之處將必須立即由其他發電機補足。但燃煤發電廠及核電廠的反應速度不夠快,一個巨型電池則能做到這一點。使用一個巨型電池,我們就能解決間歇性供電問題,防止風力和太陽能發電產生像目前燃煤、天然氣和核能發電所造成的供電不穩問題。

 

你們知道,電池是其中的關鍵設備,有了它,即使在沒有陽光時,我們也能獲得來自太陽的電力,這改變了一切。因為這樣一來,如風力和太陽能這些可再生能源,就能順利從設備中傳送到講台中心。今天我要談談這樣的設備。它被稱為液態金屬電池,這是一種新型能源儲存裝置,是我、我的學生團隊和博士後研究員在麻省理工學院的發明。

 

今年TED大會的主題是全方位(Full Spectrum);牛津英語辭典對Spectrum(光譜)的定義是:「電磁輻射的整個波長範圍,從最長的無線電波到最短的伽馬射線,可見光只佔其中一小部分。」所以,我今天在這裡要告訴大家的,不只是我在麻省理工學院的團隊如何從大自然中找到世上最偉大問題之一的解答,也想談論全方位研究,並告訴大家在這項新技術的開發過程中,我們如何發現一些令人驚奇的不尋常之處,可作為一項創新的觀念及值得推廣的想法。你們知道嗎?如果我們打算使這個國家走出當前的能源供應形態,我們不能只是保守地尋找出路,我們不能只是鑽出我們的出路,我們不能只是轟出我們的出路,我們要使用傳統的美國方式,我們要創造我們的出路-眾人齊心協力。

 

(掌聲)

 

現在我們開始說明吧!電池大約是200年前,由一名義大利帕多瓦大學教授-伏特所發明。他的發明使一個新科學領域誕生-即電化學-以及新技術誕生,如電鍍等。也許人們忽略了,伏特發明電池這件事,也首次證明了教授的功用。(笑聲)在伏特之前,沒人認為教授能有什麼作用。

 

這是史上第一個電池-一疊鋅和銀製成的硬幣,由浸在鹽水中的紙板分隔,這是電池設計的起點-在這個例子中,兩個電極由不同成分的金屬製成;在這個例子中,電解質是溶於水的鹽類。其中的科學就是這麼簡單,當然,我省略了一些細節。

 

現在我告訴大家,電池科學相當簡單,而電網級電力儲存裝置是必不可少的。但事實上,目前根本不存在符合電網所需的高性能電池技術-即不尋常的高效能、使用壽命長和超低成本。我們必須以不同觀點來思考這個問題。我們需要思考大型而便宜的設備。

 

因此,我們不妨放棄從最艱澀的化學中尋求解決之道,並希望能藉由大量生產來降低成本曲線這個固有想法。相反地,我們不妨以電力市場的價格觀點來考量,因此,這意味著元素週期表中某些部分顯然不需考慮。這種電池必須以地球蘊含豐富的元素來製造。這麼說吧,如果你想讓某樣東西像塵土一樣便宜,就用塵土來製造吧!(笑聲)最好是源於當地的塵土。我們需要製造像這樣的東西,使用成本低廉的簡單製造技術和工廠。

 

因此,大約六年前,我開始思考這個問題。為了從一個新角度思考,我從電力儲存技術的領域外尋找靈感。事實上,我尋找的是一個既非儲存也非發電的技術,而是消耗大量電力的技術;我指的是鋁生產技術。這項技術是兩個22歲的小夥子於1886年發明的,即美國的霍爾和法國的赫魯特。他們發明這項技術,短短幾年後,鋁從跟銀一樣提煉成本極高的貴金屬,成了一種普遍的建築材料。

 

圖上是一間現代化煉鋁廠的電解槽,大約50英呎寬,總長大約半英哩,一排排電解槽內部類似伏特電池,但存在三個重要差異。伏特電池在室溫下運作,它配備了固體電極及鹽類水溶液組成的電解質;霍爾-赫魯特電解槽在高溫下運作,溫度高得足以使鋁金屬產物呈液態,其中的電解質並非鹽類水溶液,而是熔融狀態的鹽。正是這種液態金屬、熔融狀態鹽類和高溫的結合,使我們能藉由這種裝置產生大量電流。今天,我們可以每磅低於50美分的成本,從礦石中提煉出原生金屬,這是現代電冶金技術產生的經濟奇蹟。

 

這就是引起我注意的想法,讓我專注於發明一種可捕捉到這種巨大經濟效益的電池;而我辦到了。我製造出完全液態的電池-兩個電極均為液態金屬,電解質為熔融狀態鹽類。我說明一下這種電池的構造。所以我將低密度液態金屬放在頂端,將高密度液態金屬放在底部,熔融狀態鹽類放在兩者之間。

 

所以,現在我要如何選擇金屬?對我來說,設計工作總是從這裡開始,藉由週期表和另一位教授-Dimitri Mendeleyev的意見。我們所知的一切都由圖上所繪的元素組合而成-包括我們的身體。回想當天那個美妙時刻,當時我正尋找一組金屬,能滿足地球上蘊含豐富、擁有不同密度,以及彼此間具有高反應性這些要求。當我知道答案就在眼前時,興奮的全身發抖。頂端用鎂,底部用銻。知道嗎?我得告訴你們,當教授的最大好處之一就是-可以用彩色粉筆。

 

(笑聲)

 

因此,為了產生電流,鎂會失去兩個電子,成為鎂離子;鎂離子會進入電解質,接受兩個來自銻的電子,然後兩者形成合金;電子進入現實世界運作,為我們的設備供電。現在,為了給電池充電,我們將它與電源連接,例如風力發電廠之類的,然後我們反向輸入電流,這使得鎂從合金上脫離,返回上層電極,使電池恢復成初始狀態。通過電極間的電流可產生足夠的熱能來保持電池的溫度。

 

相當酷-至少理論上來說。但它真的管用嗎?因此,下一步該怎麼做?我們進行實驗。現在,我需要聘請經驗豐富的專業人士嗎?不,我聘請了一位學生並指導他,教他如何思考這個問題,以我的觀點來思考,然後讓他自由發揮。就是這位學生,David Bradwell。這張照片中的他似乎正思考著,這個做法是否可行?我當時沒告訴David,我本身並不認為這是可行的。

 

但David既年輕又聰明,而且他想拿博士學位,因此他著手製造-(笑聲)他著手製造史上第一個液態金屬電池。根據大衛初步的可喜成果-這個費用由麻省理工學院種子基金支付-我得以吸引來自私部門和聯邦政府的主要研究經費,這讓我得以將研究小組擴張到20人,其中包含研究生、博士後研究員,甚至還有一些大學生。

 

我能夠吸引很棒的人參與,一些能分享我對科學及服務社會這份熱情的人,而不是對科學及建立個人成就的熱衷。如果你們問這些人,為什麼他們要研究液態金屬電池?他們的回答會像甘迺迪總統1962年在賴斯大學的演說中所言,當時他說-我自由發揮一下-「我們選擇研究電網級儲存裝置,不是因為它很容易,而是因為它很困難。」

 

(掌聲)

 

所以這就是液態金屬電池的演變過程。我們從一瓦小時電池開始研究,我稱它為「小酒杯」,我們進行了400多次實驗,以多元化的化學反應來改善它的性能-不僅使用鎂和銻。在這個過程中,我們將規模擴大到20瓦小時電池,我稱它為曲棍球。我們得到同樣顯著的成果,然後進展到碟形裝置,這是200瓦小時電池。這項技術已被證明功效強大,且具擴展性,但對我們來說,這個進展還不夠快,因此,一年半前,我和David及其他研究小組成員成立了一家公司,加速這個進展及產品製造速度。

 

所以目前在LMBC(液態金屬電池公司),我們正建造可容納一千瓦小時電量,直徑為16英吋的電池裝置,容量為最初「小酒杯」電池的1000倍,我們稱它為「披薩」。然後,我們以此為基礎,製造出四千瓦小時的電池裝置,它的直徑為36英吋,我們稱它為「酒吧桌」,但我們尚未準備好將它端上桌。這項技術的一個變化是,我們將這些「酒吧桌」堆疊成模組,然後將這些模組組合成一個巨型電池,裝在一個40英呎長的箱子裡,放置在實際設施中,它擁有兩兆瓦小時的實際容量-相當於兩百萬瓦小時。這個能量足以滿足200個美國家庭的日常用電需求,所以這麼一來,你擁有了電網級的儲存裝置,無聲、無廢氣排放、沒有需拆裝的零件、可遠程控制、以市場價格設計、不需政府補助。

 

因此,我們從中學習到什麼?(掌聲)因此,我們從中學習到什麼?讓我與你們分享其中的驚喜及不尋常處,它們隱藏在這個過程背後。在溫度方面:傳統智慧說,以低溫,即室溫或接近室溫來設計裝置,然後安裝一個控制系統,來保持這個溫度,避免熱能逸出;液態金屬電池設計為,以最小的管控在高溫下運作。我們的電池可以應付因電流輸入而產生的極高溫度。以規模來說:傳統智慧說,藉由大量生產以降低成本;液態金屬電池的設計是以降低產量來減少成本,但它們產生的效益更大。最後,以人力資源來說:傳統智慧說,聘請電池專家,聘請可借鑒其豐富經驗和知識的專業人員來開發液態金屬電池;我則聘請學生及博士後研究員,然後指導他們。以電池來說,我盡力發掘最大的電力潛能;以指導後進來說,我盡力發掘人們最大的潛力。所以你們可以看到,液態金屬電池的故事,不僅是發明一項技術的過程,也是發掘創造者的一個藍圖。全方位研究(full-spectrum)。

 

(掌聲)

 

以下為系統擷取之英文原文

 About this Talk

What's the key to using alternative energy, like solar and wind? Storage -- so we can have power on tap even when the sun's not out and the wind's not blowing. In this accessible, inspiring talk, Donald Sadoway takes to the blackboard to show us the future of large-scale batteries that store renewable energy. As he says: "We need to think about the problem differently. We need to think big. We need to think cheap."

 

About this Speaker

Donald Sadoway is working on a battery miracle -- an inexpensive, incredibly efficient, three-layered battery using “liquid metal." Full bio »

Transcript

The electricity powering the lights in this theater was generated just moments ago. Because the way things stand today, electricity demand must be in constant balance with electricity supply. If in the time that it took me to walk out here on this stage, some tens of megawatts of wind power stopped pouring into the grid, the difference would have to be made up from other generators immediately. But coal plants, nuclear plants can't respond fast enough. A giant battery could. With a giant battery, we'd be able to address the problem of intermittency that prevents wind and solar from contributing to the grid in the same way that coal, gas and nuclear do today.

You see, the battery is the key enabling device here. With it, we could draw electricity from the sun even when the sun doesn't shine. And that changes everything. Because then renewables such as wind and solar come out from the wings, here to center stage. Today I want to tell you about such a device. It's called the liquid metal battery. It's a new form of energy storage that I invented at MIT along with a team of my students and post-docs.

Now the theme of this year's TED Conference is Full Spectrum. The OED defines spectrum as "The entire range of wavelengths of electromagnetic radiation, from the longest radio waves to the shortest gamma rays of which the range of visible light is only a small part." So I'm not here today only to tell you how my team at MIT has drawn out of nature a solution to one of the world's great problems. I want to go full spectrum and tell you how, in the process of developing this new technology, we've uncovered some surprising heterodoxies that can serve as lessons for innovation, ideas worth spreading. And you know, if we're going to get this country out of its current energy situation, we can't just conserve our way out; we can't just drill our way out; we can't bomb our way out. We're going to do it the old-fashioned American way, we're going to invent our way out, working together.

(Applause)

Now let's get started. The battery was invented about 200 years ago by a professor, Alessandro Volta, at the University of Padua in Italy. His invention gave birth to a new field of science, electrochemistry, and new technologies such as electroplating. Perhaps overlooked, Volta's invention of the battery for the first time also demonstrated the utility of a professor. (Laughter) Until Volta, nobody could imagine a professor could be of any use.

Here's the first battery -- a stack of coins, zinc and silver, separated by cardboard soaked in brine. This is the starting point for designing a battery -- two electrodes, in this case metals of different composition, and an electrolyte, in this case salt dissolved in water. The science is that simple. Admittedly, I've left out a few details.

Now I've taught you that battery science is straightforward and the need for grid-level storage is compelling, but the fact is that today there is simply no battery technology capable of meeting the demanding performance requirements of the grid -- namely uncommonly high power, long service lifetime and super-low cost. We need to think about the problem differently. We need to think big, we need to think cheap.

So let's abandon the paradigm of let's search for the coolest chemistry and then hopefully we'll chase down the cost curve by just making lots and lots of product. Instead, let's invent to the price point of the electricity market. So that means that certain parts of the periodic table are axiomatically off-limits. This battery needs to be made out of earth-abundant elements. I say, if you want to make something dirt cheap, make it out of dirt -- (Laughter) preferably dirt that's locally sourced. And we need to be able to build this thing using simple manufacturing techniques and factories that don't cost us a fortune.

So about six years ago, I started thinking about this problem. And in order to adopt a fresh perspective, I sought inspiration from beyond the field of electricity storage. In fact, I looked to a technology that neither stores nor generates electricity, but instead consumes electricity, huge amounts of it. I'm talking about the production of aluminum. The process was invented in 1886 by a couple of 22-year-olds -- Hall in the United States and Heroult in France. And just a few short years following their discovery, aluminum changed from a precious metal costing as much as silver to a common structural material.

You're looking at the cell house of a modern aluminum smelter. It's about 50 feet wide and recedes about half a mile -- row after row of cells that, inside, resemble Volta's battery, with three important differences. Volta's battery works at room temperature. It's fitted with solid electrodes and an electrolyte that's a solution of salt and water. The Hall-Heroult cell operates at high temperature, a temperature high enough that the aluminum metal product is liquid. The electrolyte is not a solution of salt and water, but rather salt that's melted. It's this combination of liquid metal, molten salt and high temperature that allows us to send high current through this thing. Today, we can produce virgin metal from ore at a cost of less than 50 cents a pound. That's the economic miracle of modern electrometallurgy.

It is this that caught and held my attention to the point that I became obsessed with inventing a battery that could capture this gigantic economy of scale. And I did. I made the battery all liquid -- liquid metals for both electrodes and a molten salt for the electrolyte. I'll show you how. So I put low-density liquid metal at the top, put a high-density liquid metal at the bottom, and molten salt in between.

So now, how to choose the metals? For me, the design exercise always begins here with the periodic table, enunciated by another professor, Dimitri Mendeleyev. Everything we know is made of some combination of what you see depicted here. And that includes our own bodies. I recall the very moment one day when I was searching for a pair of metals that would meet the constraints of earth abundance, different, opposite density and high mutual reactivity. I felt the thrill of realization when I knew I'd come upon the answer. Magnesium for the top layer. And antimony for the bottom layer. You know, I've got to tell you, one of the greatest benefits of being a professor: colored chalk.

(Laughter)

So to produce current, magnesium loses two electrons to become magnesium ion, which then migrates across the electrolyte, accepts two electrons from the antimony, and then mixes with it to form an alloy. The electrons go to work in the real world out here, powering our devices. Now to charge the battery, we connect a source of electricity. It could be something like a wind farm. And then we reverse the current. And this forces magnesium to de-alloy and return to the upper electrode, restoring the initial constitution of the battery. And the current passing between the electrodes generates enough heat to keep it at temperature.

It's pretty cool, at least in theory. But does it really work? So what to do next? We go to the laboratory. Now do I hire seasoned professionals? No, I hire a student and mentor him, teach him how to think about the problem, to see it from my perspective and then turn him loose. This is that student, David Bradwell, who, in this image, appears to be wondering if this thing will ever work. What I didn't tell David at the time was I myself wasn't convinced it would work.

But David's young and he's smart and he wants a Ph.D., and he proceeds to build -- (Laughter) He proceeds to build the first ever liquid metal battery of this chemistry. And based on David's initial promising results, which were paid with seed funds at MIT, I was able to attract major research funding from the private sector and the federal government. And that allowed me to expand my group to 20 people, a mix of graduate students, post-docs and even some undergraduates.

And I was able to attract really, really good people, people who share my passion for science and service to society, not science and service for career building. And if you ask these people why they work on liquid metal battery, their answer would hearken back to President Kennedy's remarks at Rice University in 1962 when he said -- and I'm taking liberties here -- "We choose to work on grid-level storage, not because it is easy, but because it is hard."

(Applause)

So this is the evolution of the liquid metal battery. We start here with our workhorse one watt-hour cell. I called it the shotglass. We've operated over 400 of these, perfecting their performance with a plurality of chemistries -- not just magnesium and antimony. Along the way we scaled up to the 20 watt-hour cell. I call it the hockey puck. And we got the same remarkable results. And then it was onto the saucer. That's 200 watt-hours. The technology was proving itself to be robust and scalable. But the pace wasn't fast enough for us. So a year and a half ago, David and I, along with another research staff-member, formed a company to accelerate the rate of progress and the race to manufacture product.

So today at LMBC, we're building cells 16 inches in diameter with a capacity of one kilowatt-hour -- 1,000 times the capacity of that initial shotglass cell. We call that the pizza. And then we've got a four kilowatt-hour cell on the horizon. It's going to be 36 inches in diameter. We call that the bistro table, but it's not ready yet for prime-time viewing. And one variant of the technology has us stacking these bistro tabletops into modules, aggregating the modules into a giant battery that fits in a 40-foot shipping container for placement in the field. And this has a nameplate capacity of two megawatt-hours -- two million watt-hours. That's enough energy to meet the daily electrical needs of 200 American households. So here you have it, grid-level storage: silent, emissions-free, no moving parts, remotely controlled, designed to the market price point without subsidy.

So what have we learned from all this? (Applause) So what have we learned from all this? Let me share with you some of the surprises, the heterodoxies. They lie beyond the visible. Temperature: Conventional wisdom says set it low, at or near room temperature, and then install a control system to keep it there. Avoid thermal runaway. Liquid metal battery is designed to operate at elevated temperature with minimum regulation. Our battery can handle the very high temperature rises that come from current surges. Scaling: Conventional wisdom says reduce cost by producing many. Liquid metal battery is designed to reduce cost by producing fewer, but they'll be larger. And finally, human resources: Conventional wisdom says hire battery experts, seasoned professionals, who can draw upon their vast experience and knowledge. To develop liquid metal battery, I hired students and post-docs and mentored them. In a battery, I strive to maximize electrical potential; when mentoring, I strive to maximize human potential. So you see, the liquid metal battery story is more than an account of inventing technology, it's a blueprint for inventing inventors, full-spectrum.

(Applause)


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太棒了 何實台灣可用

Anonymous, 2012-06-03 21:25:54

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