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December 21, 2016

Infrequently Asked Questions: Why is smartphone battery life still so short?

Why is smartphone battery life still so short?

Only halfway through the day and your phone battery's running low? Join the club.

Despite iteration after iteration of new cutting-edge smartphones releasing every year, somehow battery life never seems to improve. 

Curious as to why, we reached out to Vibha Kalra, professor of chemical and biological engineering at Drexel University, and head of the Kalra Research Group

Getting to the gist of the big question, why is it that battery life hasn't really gotten much better in smartphones, despite new iterations coming out every year? It's almost kind of comical that technology is improving as rapidly as it is, yet battery life isn't much better than it's ever been.

The current portable electronics market, including smartphones, is dominated by Lithium-ion (Li-ion) batteries. Out of all the batteries available in the market, Li-ion offers the best capacity—battery run time—per unit of battery weight. However, these batteries, with their current material composition and configuration, have reached their theoretical limit. For a significant improvement in battery run time and life, technological breakthroughs are needed.

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There are several next-generation battery technologies, including lithium-ion with alternate materials and other technologies, such as lithium-sulfur batteries, that have much higher theoretical limits than the current state-of-the-art Li-ion technology. However, none of these are commercial yet and extensive research is needed to address the challenges associated with these new materials and chemistries.

Is it the case that battery life is sacrificed in favor of more hardware power and features? If so, what's the big battery drainer in the hardware?

The battery demands are increasing with every new OS and phone model. New features such as high-definition screens, the widgets that provide handy information on the home screen and many new apps are big battery drainers.

Why do you think manufacturers aren't putting more effort into having a power-efficient phone instead of beefing up specs every year? You'd think a high-battery-life phone would be a big seller.

Absolutely, a high-battery-life phone would be a big seller. Who wouldn't like their phone to stay charged for two days and still have all the new power and features! The manufacturers are limited by the battery technology available in the market.

What are some of the latest advancements in improving battery life? (Are there any?)

In the recent past, the overall battery technology in the market has remained the same. The manufacturers are able to make incremental improvements in this technology, which has reached its theoretical limit, for example, by thinning down some of the inactive—but necessary—components of a battery to reduce weight and effectively increase capacity -- i.e., run time.

One example of this is Samsung thinning down the separators in the Galaxy Note 7. These materials electronically separate the negative and positive sides of the battery. Samsung posited that they didn’t need to be as thick as they were, but this decision, unfortunately, led to the safety issue that we all know about. 

For real battery life improvements, extensive research is needed on next-generation Li-ion batteries, as well as beyond Li-ion technologies. Researchers both from academia, including my lab at Drexel, and small and large companies are heavily involved in these studies. 

Is there a kind of phone that tends to have a better battery life?

As phones are getting more and more powerful with all these additional features, loss in battery life is unavoidable, because we’re using the same battery technology. Perhaps a phone with no apps will have a great battery life!

Any general tips for preserving battery life?

A good way to reduce the loss in battery life over years of usage is to try not to let it die completely. Keeping your phones in a cool environment will also help preserve the battery life. They tend to degrade much more in a hot environment. Battery run time can be greatly enhanced by optimizing phone settings such as dimming the screen, enabling power saver mode, turning off GPS when not in use and disabling background app refresh.

Anything you think people should know?

Something that many people may not realize are the limitations of the energy storage technology, such as batteries, are not just affecting the size and life of our mobile devices, they’re also a major limiting factor for our use of renewable energy. We have made great progress in extracting energy from the wind and the sun, but the problem is that we don’t have the energy storage technology to hold all of it and disburse it quickly, on-demand. Researchers are working hard to develop better technology for this. But it’s something to keep in mind the next time you see a giant wind turbine or a rooftop laid with solar panels.