It takes about 4,500 pounds of force to make a Samsung Galaxy S8 battery explode. I know because I saw it at Samsung’s test center: a metal plate slamming down hard on the battery with a ker-chunk, then a pause, and then the flames.
Fortunately, that’s far more force than most people can deliver. It’s more than the weight of a Toyota Camry or a Honda Accord. It’s about the weight of an adult rhinocerous, but remember, that’s the whole rhino—not just one foot.
Samsung took PCMag to its factory in Gumi, Korea, where it makes Galaxy S8 phones for AT&T and Verizon, to show off its eight-point battery safety check in the wake of the Galaxy Note 7 disaster.
“We’re sharing why it happened, what happened, and why it won’t happen again,” Samsung EVP of global marketing, YH Lee, told me separately at Samsung’s headquarters in Suwon, Korea. “I think we can regain a little bit of trust, and we are seeing our customers as generous enough to say that, ‘I believe in Samsung, and a one-time mistake is excusable.'”
To that extent, Samsung held a lunch with its “battery advisory group” of chemistry professors from Cambridge and Berkeley, and led a few of us on a tour of its production plant, with a focus on safety. I’ve been to the Gumi plant before, where legions of young women fit circuit boards into shiny phone cases while huge robots trundle around carrying heavy loads of boxes.
The Galaxy S8 construction process is a lot more automated than when I saw the Galaxy S5 built in 2014. Cases and screens get shipped in from other plants. Robots, which look like giant printers, attach chips to circuit boards, which humans press into the phone cases and snap together. Then other robots run the phones through a battery of tests, spitting out phones that fail. That happens surprisingly often: while I was standing in front of the USB OTG testing machine, a phone popped out with a big marker slash across it.
It takes about 13 minutes to put together a physical phone, or half an hour including software loads, Samsung reps said.
Humans come back into play in the “accelerated usage test,” a new level of QA that’s come into play after the Note 7 mess. The AUT consists of five days of fast charging, discharging, dunking phones in water, and putting them through the paces of browsing, calling, Facebooking, and game playing. While camera testing was being done by technicians, a rack full of phones in another room scrolled through an automated browsing test. Since Gumi makes phones for the US and Korea, the room had simulated US and Korean networks—probably the only place in Korea where your AT&T phone would get a Band 17 signal.
Not every phone gets tested; there’s some sampling going on. On the “battery life cycle” test rack, where refurbished Note 7s were acting as webcams over racks of new Galaxy S8s, Samsung was testing 300 phones out of the first 15,000 made by churning their batteries through 400 charge cycles in 50 days. That’s typically about a year and a half of use.
But Samsung’s doing a lot more samples than it used to. In a room with big, cheerful stickers reading “Safety Always!” two white-coated engineers disassembled a battery under a ventilation hood to check for assembly problems. That’s a test that used to only be done by the battery manufacturers.
“We didn’t do the teardown test of the battery with the Note 7,” Koh pointed out.
Another room had the rough-and-tumble tests, which I’ve seen other manufacturers and carriers do, like the 4-foot drop to concrete (which didn’t break the Galaxy S8’s new Gorilla Glass 5 screen); the fake human butt wearing jeans, sitting down with the phone in a back pocket; and that metal press, which doesn’t usually deliver 4,500 pounds of force.
Three out of the eight battery-related tests are new, Samsung said: the charge-discharge and accelerated usage tests I just described, as well as a “total volatile organic compounds” test looking for leakage from the batteries.
“Meaningful innovation should keep going, but on top of it, we will keep as a top priority customer safety,” Samsung mobile CEO DJ Koh said. “It will take time, but I strongly believe I can bring our customers’ trust back.”