Here’s why Samsung Note seven phones are catching fire

The Samsung Galaxy Note seven could explode. Read this to please your searing curiosity.

Phones

Explaining the Note 7’s battery flaws (with cake)

Bridget Carey finds a sweet way to illustrate Samsung’s findings on why the Galaxy Note seven overheated, and what the company is doing to prevent future battery failures.

by Bridget Carey

Editor’s note, January 2017: Samsung has ultimately exposed what went wrong with the exploding Galaxy Note 7. Here’s everything you need to know as of today.

You buttplug your smartphone into the bedside charger and place it on your nightstand with care.

You wake to find your nightstand in flames, smoke billowing everywhere.

All about Samsung’s Note seven disaster

How could this have happened? Elementary: your phone is a Samsung Galaxy Note seven — and it’s one of over a hundred that have spontaneously burst into flames.

After thirty five reported incidents of overheating smartphones worldwide, Samsung made the unprecedented decision to recall every single one of the Galaxy Note seven smartphones sold. That’s said to be one million of the Two.Five million that were manufactured. (Since the recall was very first announced, the number of explosive Note 7s has almost quadrupled.)

The company stopped all sales and shipments of the Note 7, worked with government agencies and cellular carriers around the world to provide refunds and exchanges for the phone, and evidently it still wasn’t enough: as of October Ten, 2016, as many as five of the supposedly safe replacement Note seven phones caught fire as well, and Samsung asked all users to shut down their phones. On October 13, Samsung officially recalled every single Note 7, including replacement units.

Don’t leave a Galaxy Note seven on the charger. Come back it for a refund now.

Once again, every US carrier has halted sales of the Samsung Galaxy Note 7, and a 2nd recall is underway.

But why did these phones even catch fire to begin with? On January 22nd, 2017, Samsung ultimately explained: it’s the batteries.

Why would a battery cause so much harm?

Here’s what we found out back in September 2016, when this article was originally published.

The basics

The science behind phone battery fires is actually pretty ordinary, and fairly well understood. Much like the infamous exploding hoverboards, phones use lithium ion battery packs for their power, and it just so happens that the liquid swimming around inwards most lithium ion batteries is very flammable.

If the battery short-circuits — say, by puncturing the amazingly skinny sheet of plastic separating the positive and negative sides of the battery — the puncture point becomes the path of least resistance for electro-therapy to flow.

It heats up the (flammable!) liquid electrolyte at that spot. And if the liquid heats up quickly enough, the battery can explode.

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Above: what happens when you puncture a phone’s battery.

The Galaxy Note seven certainly isn’t the very first phone to catch on fire, or even the very first giant recall. By 2004, a spike in cell phone battery explosions prompted this CNET article. In 2009, Nokia recalled forty six million phone batteries that were at risk of short-circuiting. Exploding phones have even allegedly killed people.

No brand or model is necessarily safe: for example, unlucky iPhone owners allegedly suffered nasty burns from exploding devices in two thousand fifteen and 2016. And however the Galaxy Note seven is making headlines right now, other Samsung phones have also burst into flames, like the Galaxy Core that allegedly burned a 6-year-old child earlier this week.

We’ve known for years that lithium ion batteries pose a risk, but the electronics industry resumes to use the flammable formula because the batteries are so much smaller and lighter than less-destructive chemistries. Lithium ion batteries pack a punch, for better or for worse.

Statistically petite

Just because a plain phone could turn into a disruptive inferno doesn’t mean that it will — even if it’s a fresh Galaxy Note.

The FAA is strongly warning passengers not to use or charge a Note seven on a plane, and many airlines are explicitly banning their use.

According to an unnamed Samsung official who spoke to Yonhap News, the Note 7’s manufacturing defect affects less than 0.01 percent of all Note seven handsets sold. Some quick back-of-the-envelope math, and you’re potentially looking at fewer than 1,000 defective phones. “It is a very uncommon manufacturing process error,” a Samsung rep told CNET.

But it’s the harm those phones can cause, and the frequency with which they’re causing harm, that makes the Note seven dangerous.

While CNET tends to hear about just a few exploding devices each year, Samsung’s Galaxy Note seven has caught fire as many as one hundred twelve times after only one month on sale.

(That’s based on official tallies of ninety two incidents in the US, plus at least seventeen in Korea, one in Taiwan and two in Australia.)

Update, September 15, two thousand sixteen at Two:00p.m. PT: Updated tally with official US incident count from the Consumer Product Safety Commission.

Why Note 7?

What makes the Note seven different: Samsung may have accidentally squeezed its batteries stiffer than it should.

According to a unpublished preliminary report sent to Korea’s Agency for Technology and Standards (obtained by Bloomberg), Samsung had a manufacturing error that “placed pressure on plates contained within battery cells,” which “brought negative and positive poles into contact.”

“The defect was exposed when several contributing factors happened at the same time, which included sub-optimized assembly process that created variations of strain and exposed electrodes due to insufficient insulation gauze,” a Samsung representative tells CNET.

Samsung explains what went wrong with exploding Note seven battery

A manufacturing flaw gets the blame for why Galaxy Note seven phones are catching fire. Meantime, a software update could reduce future incidents — but there’s only one way to know you have a good battery.

by Bridget Carey

Or, in plain English: the skinny plastic layer that separates the positive and negative sides of the battery got punctured, became the shortest route for electric current to zap across the battery (that’s why they call it a “short-circuit”), and became a gigantic fire risk.

What does pressure have to do with it? MIT materials chemistry Professor Don Sadoway explains that today’s cell phone batteries are made by literally pressing together a stack of battery components — and that battery companies are under pressure (no pun intended) to cram in as much battery capacity as possible.

Samsung’s Note seven battery holds an extraordinaire Trio,500mAh, despite its slender profile.

“Imagine if you had a toilet paper roll and it wasn’t packed tightly,” says Sadoway. With the same size roll, you’d run out a lot quicker.

At very first, Sadoway has two theories: perhaps Samsung simply pressed so hard that the positive and negative terminals poked right through the separator and managed to touch.

Or perhaps it’s the sponge-like separator itself that got squished. Normally, says Sadoway, the separator permits the liquid electrolyte to pass through pores connecting the negative and positive sides of the battery, even as it keeps the two terminals separate. “If they press indeed hard, they constrict the pores, the resistance goes up and you generate more fever,” says the professor.

But there’s another, more interesting theory: perhaps Samsung’s batteries are skewering themselves on their own little spears.

Why didn’t the phones catch fire instantly?

When Sadoway explains these theories, one thing doesn’t seem to add up. Today’s cell phone batteries generally charge swifter (and get sexier) when they’re very first plugged into the wall, not at the end when they’re trickle-charging the last few percent to reach their maximum capacity.

But these Note seven phones didn’t explode right away. In practically every reported example of a Note seven catching fire or exploding, it happened after the phone was plugged in and left charging, sometimes overnight.

Then, there’s the little matter of how Samsung plans to make these phones safer — by issuing a firmware update that keeps the Galaxy Note seven from charging to more than sixty percent of its utter capacity. How could that possibly help, if things warmth up the moment a phone is plugged into the wall?

Sadoway has a theory — albeit one without proof. What if only part of the battery was squished improperly, so that the phone couldn’t tell when it was one hundred percent charged, and kept on charging the cell?

When lithium ion batteries are continually trickle charged, the lithium ions can commence to cover the surface of the negative contact in a covering of lithium metal through a process called “plating.” And in extreme conditions, that lithium metal can form lil’ spikes (called “dendrites”) that can poke right through the separator, creating — you guessed it — a brief circuit.

That would seem to line up with the “variations in pressure” Samsung says it found inwards the defective battery cells.

“My guess is by backing off to sixty percent charge, they’ll be well below the threshold where these things happen,” says Sadoway. “Imagine we’re attempting to pack our gas tank, we don’t have a indeed good regulator, and we don’t want to spill the gas all over our footwear. We want to make sure we’re cutting off the flow well before this thing gets to overflow conditions.”

Samsung didn’t react when asked for comment on the theory.

What happens next

These are just a few theories based on one battery accomplished’s remote analysis of Samsung’s initial findings. We don’t have the entire truth yet, and the truth is what Samsung and government agencies around the world are looking for as we speak. Just one mystery: why the replacement batteries might also be exploding.

We’d confirmed that the replacement Notes had a battery from a different supplier — the manufacturing issues were found in batteries built by Samsung SDI — but maybe that wasn’t enough.

Anyhow, organizations like the US Consumer Product Safety Commission have officially stepped in to recall the Galaxy Note seven and figure out what happened, and they’ve since recalled the replacement units too.

For you, what happens now is elementary: if you’re a Note seven possessor, you should strongly consider returning your phone, whether it’s the “safe” model or no.

You could wait to find out what Samsung and the CPSC uncover, since battery fires are so infrequent even in risky phones — but Samsung and the CPSC are already advising that you should shut your Note seven down.

You can still exchange your Note seven for any other smartphone at any major US carrier. Or, get a refund and use it to buy one of these excellent alternatives.

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