????今天的汽車工廠不再像上世紀的先輩那樣嘈雜臟亂。在這個方面，位于美國田納西州士麥那的日產（Nissan）全新鋰電池工廠以其實驗室般的整潔環境更進一步。

????這家工廠價值3億美元，配備了100名工人。他們許多身著白色工作服，在干凈房間里的自動化機器旁邊，忙著生產用于電動汽車日產聆風（Leaf）的電池包。聆風最初銷量不佳，如今卻由于日產今年1月起實行的大幅折扣而漸有起色。

????日產電動汽車戰略的負責人布蘭登?瓊斯說：“聆風的買家熱情得讓人難以置信。”他表示，聆風正在發展狂熱的追隨者。“從來沒有一款車像聆風一樣，有眾多車主給我們打電話、跟我們聊車、給我們提出改進建議。”

????聆風的車身同Altima和Maxima一起，在附近的生產線進行組裝——不過聆風沒有引擎和汽車油箱，取而代之的是重達600磅的電池包和電動馬達。在美國制造聆風和配備的電池可以維持較低的運輸成本。此舉也表達了日產對美國于2007年借款14億美元支持此項目的感激之情。

????不過平心而論，如果當初不是因為加利福尼亞州政府要求（而且如果美國不允許加利福尼亞州如此要求）提高零排放車輛的銷量來遏制尾氣污染，日產就不會制造電池或電動汽車了。上個月，汽車行業向美國環保署（U.S. Environmental Protection Agency）請愿，希望政府取消到2025年銷售140萬輛電動、混合動力和燃料電池汽車的要求。

????鋰電池技術是安全問題的爭論焦點。盡管這種電池盡管功能強大，但卻會產生大量熱量。因此制造過程需要一絲不茍，而且可能很棘手。工作中的鋰電池必須謹慎處理，以防止產生導致波音787夢想客機最近被禁飛的類似問題。

????日產的電池在鋼鐵模組間加入了一系列層壓薄板，而且置于客艙的下部。它可以通過空氣散熱，而其他廠商的電池則需要使用液體冷卻劑。

????日產的本國頭號競爭對手豐田（Toyota）在油電混合動力車上并沒有采用鋰電池技術，暗示著在其他類型的電池化學技術上，他們預見到了突破性的進展。

????Modern auto factories hardly resemble their noisy, dirty, chaotic forebears of the previous century. Nissan Motor Co.'s new lithium-ion battery plant in Smyrna, Tenn. goes one step further with an atmosphere reminiscent of a laboratory.

????The $300 million factory, which operates with 100 workers --many clad in white smocks, toiling away amid robotized machines in clean rooms -- manufactures battery packs for the electric Nissan Leaf. The Leaf's initial slow sales are perking up, thanks to steep discounting announced by Nissan in January.

????"The people who buy the Leaf are incredibly enthusiastic," said Brendan Jones, Nissan's (NSANY) head of electric-vehicle strategy. Leaf, he said, is developing a cult-like following. "We've never sold a vehicle that has had so many of its owners calling, talking, suggesting ideas for improvements."

????The Leaf body is assembled nearby on a production line along with Nissan Altima and Maxima -- but instead of an engine and gas tank, it gets a 600-pound battery pack and electric motor. Building the Leaf and its battery in the U.S. keeps transportation costs low and reflects appreciation for $1.4 billion the U.S. lent to Nissan in 2007 for the project.

????Fair's fair, after all, since Nissan mightn't be manufacturing batteries or electric vehicles if California didn't mandate (and the U.S. didn't permit California to mandate) the sale of a greater and greater number of emission-free vehicles in the state to combat smog. The auto industry last month petitioned the U.S. Environmental Protection Agency to drop the requirement to sell 1.4 million electric, plug-in hybrid and fuel cell vehicles by 2025.

????Lithium-ion technology has been the center of debates over safety because the batteries, while powerful, tend to generate quite a bit of heat. The manufacturing process, therefore, is precise and can be tricky. The batteries while in operation must be managed carefully in order to prevent problems of the type that recently grounded the Boeing (BA) 787 Dreamliner.

????Nissan's battery design, a series of laminated sheets inside steel modules, is buried below the passenger cabin. Its heat is dissipated by air; designs by other manufacturers require a liquid coolant.

????Nissan's top Japanese competitor, Toyota (TM), has avoided lithium-ion technology in its gas-electric hybrids, hinting that it foresees a breakthrough in some other type of battery chemistry.