Battery technology seems stuck in the dark ages. Nicole Kobie examines its limitations and reveals the research that could cause a power revolution.
Smartphone screens are getting bigger and sharper, processors are ever-more powerful, but battery life continues to be the bane of our ongoing mobile existence.
No wonder, then, that a recent pair of surveys showed battery life as one of the key considerations when buying a smartphone. Global Market Institute found that 89% rated a phone’s battery life as “important” – far more so than the 68% who chose by the brand of the handset – and said extending time between charges was so crucial to users that some turned off key features or turned down screen brightness in order to extend battery life. A separate study by uSwitch revealed that 89% of Britons would be more likely to buy a smartphone purely based on longer battery life, rather than more flashy features such as voice controls, flexible displays or even 3D graphics.
But forget week-long battery life: manufacturers are fighting to provide us with a single day between charges, according to IHS iSuppli analyst Thomas McAlpine. “From discussions with battery manufacturers, the industry standard in smartphones is a battery that will last one full day during average use,” he says. “This is one of the benchmarks that manufacturers aim to achieve.”
That doesn’t mean manufacturers aren’t trying to improve upon this: contrary to the impression, capacity in smartphones is actually increasing. The iPhone 4 battery had a capacity of 1,420mAh; four models on, and the iPhone 5s has 1,560mAh, which is a decent improvement given the handset itself is smaller. In 2010, the Nexus One launched with a 1,400mAh battery; the larger Nexus 5 arrived in October 2013 with a 2,300mAh unit.
POWERING UP
McAlpine puts the average increase at around 7% annually, pointing out that it may have gone unnoticed because the power has been sucked away by shiny new specifications and apps. “We have seen that this hasn’t been enough to meet the annual increase in power demands for a smartphone,” says McAlpine. “This increase in power is partly due to advancements in smartphone technology, such as the move from 3G to 4G/LTE, improvements in mobile displays and more advanced powerintensive processors. In addition, consumers are changing their habits and running a greater number of apps, which in themselves are becoming more power-hungry.”
This is one way that handset manufacturers are extending battery life: rather than mess with the lithium, they’re trying to cut down on demand. For example, HTC’s “Extreme Power Saving” mode, introduced with the HTC One (M8), limits the phone to its basic functions to keep it running longer, turning off vibration for notifications and background updates for apps, conserving CPU use and reducing screen brightness.
There’s another obvious way to improve battery life: use bigger ones. “If you look at phablets and many of the best-selling smartphones, their size has increased partly to allow for a larger screen, but also to house a larger battery,” notes McAlpine. “We are now getting to the limits in terms of the size of smartphones, so the technology of the battery is becoming increasingly scrutinised.”
LEADING THE CHARGE
Despite the challenges, smartphone batteries are improving thanks to tiny technological tweaks. Just as chip designers make small improvements to squeeze more performance out of processors, the same is true of lithiumbased batteries. “Battery-management circuitry that protects and monitors the battery is improving, so manufacturers are able to push the lithium-battery chemistry to the limits of its capabilities,” says McAlpine. “One of the easiest ways to improve this is to increase the peak voltage of the lithium cell. In recent years, the peak voltage has gone up from around 4.15V to 4.35V, which has enabled the capacity to increase. Over the next five years, this is predicted torise even further to around 4.5-4.6V, which stillleaves room for a significant improvement in battery lifetime.”
However, getting it wrong is risky – it’s far more dangerous to push batteries to their limits than it is to push processors. “One of the greatest limitations is the safety of the battery,” says McAlpine. “Lithium is inherently volatile, so there’s always the risk of combustion, which can lead to fires.”
While such efforts should enable smartphones to last a full day between charges, there’s no technological revolution in the immediate pipeline tosee them last a week. The nextfivetoten years is a different matter: researchers are developing technologies that could improve the situation in that timeframe (see Batteries of the future, right).
NEW PROTOCOLS
“I don’t currently see a viable technology that can compete with lithium-ion batteries in smartphones over the next two to five years,” McAlpine says, but he goes on toexplain that this doesn’t mean thatinnovation in device charging will stand still. “Wireless and fast chargingare two new protocols that are predicted to appear in many smartphones overs the next five years, which will make charging much more convenient, and could help tackle someof the limitations in battery lifetime in the short term.”
In other words, you’ll still have to charge your smartphone each night, but it will be quicker and easier. While this may not be a perfect solution, it’s certainly a start.