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Mobile computing will still be gasping for air time at CES

Mon, 11/26/2012 - 9:47am
Noam Kedem, Leyden Energy

International CES 2013 will feature more efficient untethered devices, better access to power on the go, but virtually no battery breakthroughs

The world is going untethered, with computing no longer tied to the home or office. Business is getting behind this in a big way: according to Cisco, over a third of the U.S. workforce is now completely mobile, and Bring-Your-Own-Device (BYOD) programs are taking off. Alfonso Velosa, a research director at Gartner, states that “over half of the enterprises on a global basis are allowing employees to bring and use personal computing devices, including smart phones and tablets, for work.” Both consumer and business mobility depend on the developing cloud, an increasingly diffuse set of public and private computing resources available via the Internet.

As a result, data storage and processing are floating off into the cloud. For instance, the Google Chromebook comes with 16 GB of local solid-state storage as a mere “thumbnail” of the actual user content stored on the 100 GB of cloud storage free for two years in Google Drive. Many smartphone and tablet applications depend on processing in the cloud, such as Apple’s Siri, Waze or Google Translate.

Unfortunately, you can’t yet get power from the cloud (paging Nikolai Tesla!), and the advanced mobile processors and wireless connectivity that make all this possible draw a lot of it. The legacy Lithium-ion (Li-ion) battery chemistry used in virtually all mobile devices can’t deliver it, resulting in smartphones that won’t last through the day, and computing as a constant quest for the next power outlet. We need longer-lasting batteries, better access to charging opportunities and lower-powered semiconductors. Unfortunately we’ll likely only see the latter two at International CES 2013.

The Li-ion energy gap
Strategy Analytics pointed out a widening “cellphone energy gap” back in 2009, and it’s only gotten worse because semiconductors evolve about 1,000 times faster than batteries. New processors and displays and increased connectivity are creating an explosion of new apps; indeed, CES is expected to be the world’s largest app event. These new apps produce new consumer behaviors or usage patterns that consume more power, and batteries can’t keep up. “Based on analysis of Strategy Analytics’ SpecTRAX database, the average tablet battery provides just 7.5 hours of run time (web browsing or video playback) on a full charge, with no significant increase evident in the last 12 months,” says Stuart Robinson, director of the Handset Component Technologies (HCT) Program in the analyst firm’s Strategic Technologies Practice


Heat is perhaps the biggest problem for legacy Li-ion battery chemistry, which uses an unstable, lithium salt (LiPF6) in the electrolyte. (This supplies the lithium ions whose exchange between the active anode and cathode materials is the basis of the charge/discharge cycle).

LiPF6 reacts with residual moisture left over from the manufacturing process to produce hydrofluoric acid (HF), one of the most corrosive acids known.HFbegins attacking the active materials and reducing battery capacity. Run time declines, the battery swells (and may even destructively balloon), and replacement time arrives sooner than consumers expect and demand. This is especially galling in devices with non-removable batteries.
Like all chemical reactions, this corrosion speeds up with temperature. Even a single spike in temperature can seriously degrade battery life, and it doesn’t matter where the heat comes from:


• Increasingly powerful processors, displays, and wireless connectivity
• Apps that consumers spend more and more time using (e.g., 3D gaming, HD streaming video)
• Faster charging or wireless charging, for “top up and run” mobile lifestyle
• Consumer use (e.g., in a car cup-holder in sunlight or a pocket, or using plugged in)

This thermal instability is the primary reason why you won’t see much progress in batteries this year at CES, since legacy Li-ion based on LiPF6 electrolytesis still the only game in town. I expect the 2014 show to be different. At the end of this article, I’ll mention one possibility that is already finding its way into prototype mobile devices.

Top up-and-run computing
When Li-ion batteries often can’t hold enough charge for a day’s use—or whatever interval of charging the user needs—mobile computing becomes a matter of topping-up at each opportunity and then running to the next source of power (opportune charging), or stretching out the interval with battery extenders or even apps. You’ll see a lot of activity in these areas at CES 2013.

Wireless charging is likely to be big. The Power Matters Alliance (PMA) is gaining momentum with a developing IEEE standard for wireless charging interoperability. It now includes major companies like AT&T, Google, Starbucks and Proctor & Gamble. For instance, Powermat Duracell wireless charging stations are on trial in some Boston Starbucks, and these stations can also be found throughout Madison Square Gardens, in Delta airlines lounges and gates, and elsewhere.

Conserving battery power can happen at the app end as well. Google claims Chrome now delivers 25% more battery life on Windows with GPU-accelerated video decoding. Of course, we’d rather not wait for our favorite apps to be upgraded this way, so watchdog apps that monitor and control app usage and behavior have become wildly popular. At CES I’ll be looking for more clever ideas like Carat, a free app that analyzes anonymized data from users to tell you what apps to kill for longer run time. Carat is part of a UC Berkeley research project to identify apps that abuse batteries so that developers can fix them.

More computing per milliamp-hour (mAh)
Another way to extend battery life is to produce more computing power for each mAh consumed. The new fourth-generation iPad is a good example of the benefits of more efficient (lower power draw) semiconductors. Its new A6X processor has squeezed out a bit more battery life in addition to much faster performance, and its smaller process size (32 nm) means cooler running as well. CES will also feature a bewildering array of processors, and more efficient wireless radios.

Displays are also a source of heat, especially those using LEDs to generate the light. I expect to see more devices with Sharp indium gallium zinc oxide (IGZO) displays at CES 2013, although it wasn’t ready in time for the Apple third-generation iPad. IGZO is more transparent than the usual amorphous silicon thin-film transistors that control light transmission, so less power is needed to drive the LEDs. Doubtless there will be competitive display technologies at the show as well, including e-ink types that are approaching video speeds.

The future of Li-ion batteries
Most of the burden of increasing battery life will always rest on software and semiconductors, because Moore’s Law beats chemistry every time. However, battery research is booming, with many different promising chemistries under consideration.

We expect to see some of these in mobile consumer electronics at the 2014 International CES. Some of them will feature a new electrolyte called Li-imide, which does not generate HF, is much more thermally stable, and is compatible with a wide range of anode and cathode materials. It offers more run-time for a given size and weight of battery (greater energy density), thinner batteries for sleeker devices, longer life under normal and elevated temperatures and, as a bonus, better response to the high current spikes characteristic of apps like gaming and streaming video.
 
While battery improvement will be incremental, in combination with software and semiconductors the coming generations of Li-ion technology will deliver an increasingly satisfying mobile experience, and as always, CES will be the place to see it debut.

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