The Battery: How Portable Power Sparked a Technological Revolution - Henry Schlesinger (2010)
Chapter 19. Lab Reports
“The past is a foreign country: they do things differently there.”
—L.P. Hartley, The Go-Between
What has changed over the past decade is that battery technology is now in the midst of an aggressive evolutionary process, pulled by increasingly sophisticated devices as well as by advances in pure science. For the consumer market, the goal is to build batteries that deliver greater amounts of power at higher levels and that recharge quickly. Even as consumer products have become more sophisticated, offering more energy-burning features, systems designers have struggled to keep pace, incorporating low-power modes into the IC circuitry that shut down specific functions when not in use, essentially updated technical versions of what Hamilton’s Pulsar engineers came up with by requiring a press of the button to read the LED time display.
The basic principles of battery chemistry, essentially unchanged for 200 years, have had little reason or opportunity to evolve. Consumer gadgets, by far the largest users of batteries, have more or less been designed with available and proven power sources in mind. What has changed over the past decade is the way consumers use their batteries in an ever-growing number of portable devices. In our current age of portability and increasing technological sophistication, power sources have become the weak link. Even the most advanced configurations available are very much early to mid-twentieth century chemistries powering twenty-first-century technology. The functionality and user interface of an iPod or a cell phone would probably amaze or baffle Alessandro Volta, though he would likely have little trouble grasping the basic design principles of its battery.
Of course, there have been recent success stories. The batteries used in both Gulf Wars, known as the BA 5590, has been powering up an ever-wider range of military electronics, like GPS, portable targeting systems, night vision, and portable computers for more than a decade. This is a long way from the simple flashlights and walkie-talkies of World War II. Weighing in at a little over two pounds, the BA 5590 comes in three energy flavors: Lithium Sulfur Dioxide, Lithium Manganese Dioxide, and Lithium Rechargeable (Li-ion).
So critical were the batteries, according to reliable reports, the second Gulf War was nearly halted in 2003 due to lack of batteries at the front line. It was, according to one U.S. military official, a “near-term disaster,” with the military within days of depleting its supply. What saved the day was fast thinking that saw additional batteries airlifted into the theater of operations and a quick end to the ground fighting.
The military, which has taken battery technology seriously since the Civil War, has recognized the need for even more efficient batteries and may just produce the next generation of power sources that fire up consumers’ MP3 players.
And then there’s the Hubble Space Telescope. Launched in 1990 with six, 125-pound rechargeable nickel hydrogen batteries that add up to about 460 pounds and measure 36 inches long, 32 inches wide, and 11 inches high, scientists and engineers estimated their life expectancy at around five years. In fact, they lasted some nineteen years before showing signs of diminished charging capacity. NASA attributed their world-record-setting longevity to careful management during the charging cycles along with unusually tight engineering specs. The new batteries, which were installed in 2009, are also nickel hydrogen, but manufactured using an assortment of new processes. The compounds are poured into their molds in a sludgelike consistency, and then essentially baked to eliminate the water. According to NASA, the new batteries should remain fully functional until 2013.
The six, 125-pound rechargeable nickel hydrogen batteries that powered the Hubble Space Telescope set a record for longevity. Solar charged, they were packed three to a module (one module is pictured above). Initially calculated to have a five-year life span, the batteries were nursed along by NASA engineers for nineteen years. They were eventually replaced in 2009 by a new set of nickel hydrogens that employed new manufacturing processes. According to NASA they should remain functional until 2013.
Courtesy of NASA
What does seem apparent is that portable power sources are on the verge of some very large changes. Battery life in our increasingly portable world has become a competitive issue. A notebook computer that delivers twenty hours of battery life at a stretch would have a distinct advantage in a marketplace where even the most sophisticated products are seen as commodities.
ACCORDING TO SOME EXPERTS, SIGNIFICANT improvement in traditional battery technology may be coming to an end. The last major breakthrough, lith-ion batteries during the 1990s, say some experts, brought the industry close to the end of the line of usable materials. We are, they say, at the point of incremental improvements.
One of the more promising technologies, the methane fuel cell, has been aggressively pursued by Sony. The hybrid version unveiled featured a miniature fuel cell, small enough to fit on a keychain along with a Li-ion battery. The unit, Sony pointed out, can either switch between the battery and fuel cell or run both systems simultaneously to power small devices.
Flat film batteries, already on the market, offer another solution. Flexible and no thicker than a typical playing card, they use somewhat standard chemistries in a new way. They are made up of micron- and submicron-thin layers that create the anode, cathode, and electrolyte, and researchers have to date gotten them down to about five microns or 0.00019685 of an inch thick to produce an electrical charge. While not suitable for typical consumer products, they offer enough power to run a small IC in your credit card or label on canned peas, or even small active radio frequency identification (RFID) tags, store data, or power up some basic IC hardware. This technology is already offered by TI and a few other companies for specialty applications, such as Micro-Electro-Mechanical Systems, or MEMS, that require relatively little power. And when combined with a new generation of flexible ICs, due out soon, computing power will migrate from hard, protective coverings to a wider range of applications, such as clothing capable of powering monitors for heart rate or lighting for some form of decorative display.
THE WAY WE CHARGE BATTERIES is also due to change in the near future. Plugging in a device to recharge batteries is on the way out with a variety of new technologies on the horizon. Nikola Tesla’s once fantastic-sounding dream of remote energy transmission is quickly becoming a reality. The most practical method works through a kind of induction coil that beams energy into a receiver mounted in the device, though this only works for relatively short distances or when the device is placed directly against the coil. Even more intriguing is the concept the engineers at Nokia are currently working on, which is a way to harvest ambient electromagnetic radiation emitted from things like Wi-Fi transmitters and cell phone towers that surround us every day, filling the air with energy to recharge batteries or run small devices.