VIDEO: Why Are Samsung Phones burning?

Galaxy Note 7 product recall could be the costliest in history.

As a news headline, Samsung phones are even more dominant than Donald Trump’s locker room talk.

The venerable Korean tech giant Samsung has now recalled the entire global production of Galaxy Note 7 smartphones due to an unfortunate tendency to burst in to flames. Samsung had already replaced suspect phones with an improved version, but these melted down, too, leaving the company with little choice but to spike the entire line.

It won’t be cheap.

Twenty billion dollars have been wiped off Samsung’s market value this week, and some industry analysts are currently estimating a $17-billion-dollar bill to refund owners and generally clean up the mess. The cost to Samsung’s brand isn’t known at this time; but it can’t be good, especially with the Christmas season approaching.

Most noteworthy in all the media coverage has been no mention of why the phones are burning down. To be clear, we know these issues are battery-related, and Samsung claims to have switched battery suppliers from their own Samsung SDI to Chinese supplier ATL, who also makes the batteries for Apple’s iPhone.

So if the new phones use similar batteries to Apple’s unit, why are they still failing?

The first suspects in a lithium battery fire are the polymer separators that form each battery cell. It’s called a battery for a reason: as an energy storage device, individual cells produce a little over a volt of potential, while delivering minimal current. To deliver the kind of current that a smartphone requires, multiple cells are ganged as needed to create the needed current capacity.

Current is the key. More current means more cells, which requires a bigger, bulkier battery. The smart phone industry is all about thin, so the solution is to make the cells smaller. One way to do this is to slim down the separators that regulate ion flow between anode and cathode.

If these separators break down, it’s possible to form a dead short between cells which — like any short-circuit — means a lot of current and a buildup of heat. If the pack is already running hot, the extra heat may exacerbate the problem and create a thermal runaway condition.

This is what I believe we’re seeing with the Galaxy Note 7.

But the replacement battery packs are presumably built with the same technology that Apple uses, so why would they experience thermal runaway? It may be due to packaging.

Remember, current is king and the Note 7 boasted 3500 mA hours of available current, up from the 3000 mA hours for the previous Note 5 model. Although the iPhone 7 Plus uses a similar battery technology, it uses a less powerful 2900 mA hour power pack. It’s possible that Samsung simply used too much battery in too small a case to dissipate the heat, especially when using the popular fast charging capability.

Either way, the result is one of the costliest product recalls in history. And even worse for Samsung, the Note 7 brand has been essentially destroyed, requiring the firm to not only tool up for a new phone, but then re-jig their marketing effort and the underlying charging and energy storage technology.

For Korea’s biggest company, this isn’t an issue that will sink the company, but I expect heads to roll somewhere in the ranks of Samsung engineering and product development. It’s a lesson for everyone in manufacturing, especially those who mass-produce consumer goods: you can test prototypes, preproduction and pilot units all you want, but until production units are in the hands of end-users, you never really know.

Written by

James Anderton

Jim Anderton is the Director of Content for ENGINEERING.com. Mr. Anderton was formerly editor of Canadian Metalworking Magazine and has contributed to a wide range of print and on-line publications, including Design Engineering, Canadian Plastics, Service Station and Garage Management, Autovision, and the National Post. He also brings prior industry experience in quality and part design for a Tier One automotive supplier.