电池技术革新依然遥遥无期

    如果回顾一下苹果公司(Apple)的iPhone或丰田(Toyota)普锐斯（Prius）混合动力车从最初型号到现有版本的发展过程，人们会发现技术行业一个常见的轨迹：性能翻倍提升，产品更精致，创造了无数就业岗位，甚至颠覆了整个行业。

    例如，iPhone在蜂窝网络中最大的理论下载速度已从2007年“2G”iPhone的1兆字节/秒上升至如今5s型号的300兆字节/秒。其显示屏的像素密度增加了一倍多，摄像头已从廉价的配件转变为一种实用的照相工具，而且其软件能力要比iPhone诞生之时强大太多太多。（即便是苹果应用商店如今也已发展到第二代了。）

    同样，丰田的普锐斯混合动力车从2000年的邻家怪胎（以及明星彰显其环保态度的配饰）摇身一变为日本和加州最畅销的交通工具。当前车型引擎的重量较最初型号轻了20%（总功率增加了20%），而且单次充电后行驶的里程更长。有人会说，没有普锐斯，就不会有如今的特斯拉电动车（Tesla）。

    然而在这些设备中，有一个组件这些年来一直没有变化，那就是锂离子电池。不管是在iPhone，还是普锐斯，甚至是特斯拉S车型，锂电池用的还是1991年索尼公司(Sony)推出这一产品时所用的材料。当然，这并不是说人们没有针对这种电池进行过创新。设备制造商在充电效率、冷却和控制进入手机、汽车、笔记本和USB元件的电流流量方面做得越来越好，但这些电池的芯却没有怎么换过。即便是特斯拉计划建造的50亿美元超大型电池生产厂生产的仍是（如你所料）锂电池组。

    进一步的调查发现，人们对于哪一种电池技术可能能够取代锂电池仍是众说纷纭，甚至连这方面的谣言都是寥寥无几。

    为探究其原因，《财富》(Fortune)向致力于开发下一代电池的5名知名研究人员、一名行为经济学家和一名电池行业高管提出了一个简单的问题：为什么电池技术的发展速度要比硬件慢如此之多？

    接下来你便会发现，答案的一成与化学有关，一成与心理学有关，而两成则与上述问题的反问有关：对于一项未经过二十年发展的新电池技术，一旦装上汽车，谁想成为首位驾驶该车的人？

    当今的电池技术：密度大、发热量大、问题多

    锂离子电池技术在很多方面都是移动电源的主力军。

    锂的原子量是3，如果你还记得中学化学的话，这意味着它有三个质子，非常轻，是除了氢和氦之外单位体积可填充密度最高的元素。芝加哥伊利诺伊州理工大学(Illinois Institute of Technology)物理学教授卡洛•塞格雷表示，锂的物理量为化学家们所熟知，我们几乎掌握了锂离子在电池中流动的方式。

    塞格雷说，“我认为归根结底，锂如此好的原因在于，它非常轻，而且能够轻易地穿透隔离膜。而且其产生的电压是已知材料中最高的之一。”

    锂并不是锂电池里的唯一材料，其中还混有锰（个人电子产品和交通工具）、磷酸铁（高强度工作）和其他金属。为了产生电压，这种混合物会流经另一种材料：石墨、钛溶液、硅和不同形式的碳（依情况而定）。对于大多数在相对安全的环境中所使用的非工业设备来说，流经石墨的是锂锰氧化物，因为这种材料价格低廉，相对安全，而且密度高。

    但是这一老产品也存在一些问题。这一进程会在一个高密度空间内产生热量，需要采取一些冷却措施。（例如，与特斯拉车身长度相当的液态冷却设备担负了大量的冷却工作。）传导锂离子的电解液增加了电池的重量。电芯的容量在一段时间后就会下降。充电会让锂离子回流，但这一进程可以更快一些。充满电解质的高密度锂电池在发热量超过一定程度之后有时会爆浆或爆炸，虽然这一情况很少见。

    If you were to track the upgrades for your Apple iPhone or Toyota Prius from their introduction to today, you will see a familiar arc in the technology industry: performance multiplies, the product is refined, jobs are created, even entire industries are reworked.

    Consider, for example, that the iPhone’s theoretical maximum download speed on cellular networks went from 1 megabyte per second for the 2007 “2G” iPhone to 300 mbps for today’s 5s model. Its display more than doubled in pixel density, its camera transformed from cheap afterthought to serious photography tool, and its software capabilities are far more robust than when the device was introduced. (Even the App Store is a second-generation feature.)

    Similarly, Toyota’s Prius hybrid car evolved from a neighborhood oddity (and celebrity eco-accessory) in 2000 to a best-selling vehicle in Japan and California. The engine in today’s model is 20 percent lighter (and offers 20 percent more total horsepower) than the original. Its distance-per-charge is longer. Without the Prius, it can be argued, there would be no Tesla.

    There’s is one component of all of these things that hasn’t changed in that time period: the lithium-ion battery. Whether in the iPhone, the Prius, and even the Tesla Model S, the Li-ion battery is essentially made of the same stuff as those first introduced by Sony in 1991. That’s not to say that innovation hasn’t happened around them, of course. Device-makers have become better at charging them, cooling them, and controlling how much power they draw into our phones, cars, laptops, and USB gadgets. But they’re still largely the same battery. Even Tesla’s $5 billion plans for a “giga”-sized battery factory involve the manufacture of—you guessed it—lithium-ion packs.

    Upon further investigation, there is little consensus on what kind of battery technology may replace lithium ion. There aren’t even rumors.

    To find out why, Fortune posed a simple question to five established researchers working on next-generation batteries, a behavioral economist, and a battery industry executive: Why is battery technology moving so much slower than hardware?

    As you’ll soon find out, the answer is one part chemistry, one part psychology, and two parts the answer to a counter-question: Who really wants to be the first to drive with a new type of battery that hasn’t benefited from two decades of development?

    Today’s battery tech: dense, hot, tricky

    Lithium-ion battery technology is in many ways the workhorse of portable power.

    Lithium’s atomic number is three, which, if you remember middle-school chemistry, means that it has three protons, is very lightweight, and can be packed more densely than any element other than hydrogen or helium. Lithium is a known quantity to chemists, says Carlo Segre, professor of physics at the Illinois Institute of Technology in Chicago, and we mostly understand how it flows inside a battery.

    “I think it really boils down to, the reason lithium is so good, is that it’s very light, and you can get it through a membrane very easily,” Segre says. “And the potential difference (voltage) you can generate is one of the highest we know.”

    It’s not just lithium that goes into a Li-ion battery. The element gets mixed with magnesium (for personal gadgets and vehicles), iron phosphate (for heavy-duty work), and other metals. That mixture flows into another material to create voltage: graphite, titanium solutions, silicon, and different forms of carbon, depending. In most non-industrial devices used in relatively safe conditions, you have lithium manganese oxide flowing into graphite, because those materials are cheap, relatively safe, and dense.

    But there are quite a few problems with the old faithful. The process generates heat in a dense space, requiring some kind of cooling system. (A tremendous amount of work went into Tesla’s car-length liquid cooling rig, for example.) The electrolyte that conducts lithium’s flow adds weight. The cells lose their capacity over time. Charging the battery, which makes the lithium flow back, could be quicker. And though it’s rare, we have seen that tightly packed batteries full of fluids, made very hot, can sometimes puncture or explode.