How Samsung will sell 'safe' with Galaxy S8

From tweaks to the battery to a more stringent testing process, Samsung is pulling out all the stops to ensure a safer phone.

Shara Tibken Former managing editor
Shara Tibken was a managing editor at CNET News, overseeing a team covering tech policy, EU tech, mobile and the digital divide. She previously covered mobile as a senior reporter at CNET and also wrote for Dow Jones Newswires and The Wall Street Journal. Shara is a native Midwesterner who still prefers "pop" over "soda."
Shara Tibken
5 min read

Samsung has conducted charge and discharge tests on 50,000 Galaxy S8 phones.


The battery inside the clear glass case starts to smoke and then turns red hot. All of a sudden, it bursts into flames. When the fire has died down, all that's left is the charred husk of a battery -- specifically, a battery meant for Samsung's new Galaxy S8.

No, this isn't deja vu, and Samsung's new phone isn't experiencing the same problems as its ill-fated sibling, the Galaxy Note 7. What I'm seeing is a controlled battery test in Samsung's factory in Gumi, South Korea, where the company assembles 1 million phones a month. A worker applied more pressure in a compression test than normal, causing the battery to explode.

If the battery had truly been defective, Samsung would have returned the entire lot to its supplier, potentially as many as 15,000 units. "It very seldom happens," a worker in the durability testing lab says as I tour the facility two weeks before this week's introduction of the Galaxy S8.

Watch this: What I saw inside Samsung's battery testing center

Samsung got burned by last year's Galaxy Note 7, and it's determined not to let that happen again. The company added a more stringent battery testing process, which it says exceeds industry standards. It also lowered the capacity of the battery going into the Galaxy S8 and tweaked its chemistry so it lasts longer.

All of this effort goes into ensuring that the Galaxy S8, with its sleek, curvy 5.8-inch display, is Samsung's safest phone ever. The stakes are high for the company to prove that it can still turn out high-quality products -- if any more battery issues flare up, the company will likely never win back your trust. A flawless launch will help Samsung move past the Note 7 debacle, something it's eager to do.

"We set up our own standard ... but we didn't keep it," Koh Dong-jin (better known as D.J. Koh), head of Samsung's mobile business, tells me from the company's sprawling Digital City campus in Suwon, about 21 miles outside of Seoul. "It was an eye-opening experience."

Longer-lasting batteries

Samsung's development on the Galaxy S8 was nearly done by the time the Note 7 started having problems. But that didn't stop Samsung from making some changes to the new phone's batteries.

The company lowered the capacity in the Galaxy S8 to 3,000 mAh and in the 6.2-inch Galaxy S8 Plus to 3,500 mAh. That's less than in last year's S7 Edge, which had a 3,600 mAh battery. Samsung hasn't talked about battery life on the new phones, but said they should last longer thanks to energy management software and other tweaks.

Samsung also made the battery longer-lasting through hundreds of recharges. After about six months to a year of use, the Galaxy S8 will have better battery life than its predecessor, the company says. And it will continue to hold a charge better after even two years. That's because Samsung focused on making the battery more durable and able to withstand hundreds of charging cycles.

"Where most batteries hold about 80 percent of their charge after two years, this battery should be capable of 95 percent of its original capacity," said Oh Boo-keun, vice president of Samsung's mobile R&D team, who oversees the division's battery technology development.

New safety tests

Samsung, which has built nearly 4 billion phones since 1988, was caught by surprise by the Note 7 problems. Like most companies in the mobile industry, Samsung had counted on its battery suppliers to conduct safety tests before putting the batteries in devices. As it turned out, those suppliers didn't catch the errors that caused the Note 7 to overheat.

Samsung is now doing many of those tests on its own, as well as conducting new tests that would help it catch any battery flaws.

An inside look at Samsung's new battery tests

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"They can't take any chances, so they're sort of double testing and making sure that, even on their side, they would detect any potential problem," said Gerbrand Ceder, a professor of materials science and engineering at the University of California, Berkeley. He's also a member of Samsung's new battery advisory board. "They're doing more than all the right things."

During my time on Samsung's campus in Gumi, also called Smart City, I get to see most of Samsung's eight battery tests in action.

One is a durability test that examines the battery when it's been overcharged, punctured by a nail or exposed to extreme temperatures. That compression test I saw, in which the battery exploded, is part of the expanded durability test. I also see a phone being baked at 130 degrees Celsius (266 degrees Fahrenheit) for 60 minutes and another being heated at 70 degrees Celsius (158 degrees Fahrenheit) for seven hours.

In addition, Samsung workers will visually inspect each battery and do an X-ray test to check for abnormalities. They disassemble batteries to inspect the overall quality and use tools to check for leakage of the battery components and for any change in voltage through the manufacturing process.

As I walk along the floor, there's a constant hum in the air from long rows of phones, perched on black foam-covered shelves, charging and discharging. Refurbished Note 7 phones dangle from selfie sticks above the Galaxy S8 devices, recording the tests to make sure no potential problems are missed. In Gumi, Samsung can test 60,000 phones for charge and discharge. When I'm there, 6,000 are being checked.

An area walled off from the rest of the open factory floor is where Samsung runs dozens of phones through its accelerated usage tests, looking at everything from charging and discharging to waterproofing. An Android Control Test simulates daily phone usage -- like playing Angry Birds or loading videos on YouTube -- at a much faster clip than normal. Workers, wielding orange laser thermometers, check how hot the devices are.

Overall, it takes five days for a phone to complete Samsung's accelerated usage tests, in part because there's no way to speed up a battery's discharge rate. Samsung plans to test a "massive number" of its devices -- up to 100,000 units -- in this way before they're sent to customers. By the time I visit, before Samsung has sold a single Galaxy S8, it has tested 50,000.

Experts question how long Samsung will be able to keep up these tests -- they're time-consuming and expensive -- but for the Galaxy S8, no expense is too much.

"We realized we must increase the safety of our device as well as the battery," Koh said. "Meaningful innovation should keep going where we can make our customers happy continuously. But on top of it all, keep as a top priority customer safety."

South Korea beyond Samsung

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