标签: density

We are aware that battery capability, which is primarily defined using energy density by volume and by weight, is a criucial factor in determining what we can expect of the units they power. Pundits at all levels of technical knowledge from near-zero to quite advanced keep reminding us of this obvious fact, and then opine on what they think will or should happen next. In many cases, these writers have an agenda (of course, a common one is "send us more grant money and funding so we can finish the job"), so it's hard to separate facts from hopes and wishful thinking.   That's why I was impressed by a recent article in The Wall Street Journal, " Tech World Vexed by Slow Progress on Batteries ," which I thought was one of the best and clearest assessments of the present status of battery technology and advances I have seen. The article made two points:   There have been significant advances in the last few years that have made many products practical, including smart phones and battery-powered tools. (The author cites specific examples.) Although each advance may have been modest in itself, they do add up to a genuine and substantial increase in performance metrics. The much-vaunted "breakthrough" that everyone wants, hopes for, or claims they are "this close" to, just isn't in sight. When you step back and look at the bigger picture, there's certainly been progress, but it has been in incremental layers, not major leaps. The breakthrough to allow practical batteries that are much, much lighter in weight, denser in capacity, and lower in cost (hopefully, all at the same time) is not just around the corner. It seems that we are bombarded with researchers claiming that they on the path for the breakthrough, but that hasn't materialized when you peel back the hype.   The supposed imminent "quantum leaps" (a very misused phrase) are really just modest advances of varying degrees, not game changers or "paradigm shifts," to use another cliché. Further, translating even a modest prototype battery improvement into actual volume manufacturing and OEM adoption is a long-term undertaking -- on the order of ten years or more. Regardless of the technology or chemistry you have, battery manufacturing is a very capital- , materials-, and production-intensive process.   There's another problem with supposed breakthroughs: You can only recognize them in retrospect, so you need the perspective of hindsight. It's like peak detection, in that you can only determine that you have had a peak after it has passed. Breakthroughs are very hard, if not impossible, to see as they approach or even as they happen, and it is even harder to see how they will really unfold. Consider these major breakthroughs in our industry: The transistor (1947) was demonstrated as an analog amplifier. Its role as a digital-switching building block was not really foreseen. The integrated circuit (1958) was an analog audio oscillator. The impact of large-scale integration for digital functions was not apparent. The laser (1960) was called "a solution in search of problems to solve" by observers. We know how that situation turned out!   While there may be a genuine order-of-magnitude battery breakthrough at some point, perhaps it will have an underlying principle that is fundamentally different from the electrochemical devices we now know as batteries. Maybe there will be a mini-fusion device (no, not the discredited cold fusion), something using an electrochemical basis quite different from what we know of, or even a device with a non-chemical basis for an entirely new type of battery.   After all, it's naive to think that we already are aware of all the basic processes that can happen at the molecular level and just have to work harder and smarter with them. The history of advances in science and engineering has many examples of cases where everything was presumed to be known, except that it wasn't. (See the insightful but very densely written classic The Structure of Scientific Revolutions by T.S. Kuhn, or at least get a readable summary of it.) There have been times where disparate advances come together in ways no one anticipated. (See the series Connections by James Burke.)   What's your assessment of the true state of battery technology advances and hype-versus-hope reality?