Galaxy Note 7 Teardown Reveals a Rookie Mistake in Electronics Design

December 09, 2016 by Tim Youngblood

A report detailing the design flaws of the Galaxy 7 Note cited a cramped battery housing as the primary culprit for their tendency to explode. How does something like this slip through the cracks?

A report detailing the design flaws of the Galaxy 7 Note cited a cramped battery housing as the primary culprit for their tendency to explode. How does something like this slip through the cracks?

In Case You Haven't Heard...

Unless you've been living under a rock or on that lonely island on a remote planet where Luke Skywalker was found, you've probably heard about Samsung Galaxy Note 7 batteries exploding and their subsequent recalls. The situation has been such a hot topic that you could spend an entire day just looking at the internet memes that have spawned as a result. (A word of warning: many of them are pretty offensive.) 

The Galaxy Note 7 phenomenon has trickled into our lives in more than just the news, which you've probably noticed if you've been on an airplane lately.


Image courtesy of Tom's Guide

A Rookie Mistake

Just when the Galaxy Note 7 craze was starting to die down, it came back to the forefront of the news. On December 2nd, Instrumental (an assembly line data startup) released a post detailing why Samsung Galaxy Note 7 batteries have been exploding. In the last week, the post has gone viral, catching fire (too soon?) in the electronics blogosphere. It was written by Anna Shedletsky, the CEO of Instrumental, and gives insight into a teardown they performed with one of their own inspection stations (I suppose I can't fault them for good product placement).

The primary takeaway is that the design didn't allow enough space for natural expansion of the battery. Lithium ion batteries swell a little when they are charged and discharged. As a result, battery engineers recommend leaving some extra room in the battery's housing to accommodate it. This space is referred to as a ceiling, and the Note 7's ceiling was shown to be non-existent.

According to Instrumental's teardown, the 5.2mm battery was laying in a 5.2mm ceiling, meaning that there was no room whatsoever to account for battery swelling. This is bad for a device that sits on a desk like a computer. But for a mobile device, which runs into environmental factors like being dropped or sat on, it can be catastrophically bad. Pair this with the nature of lithium ion batteries, which generate a lot of heat, with no room for said heat to dissipate, and you have a recipe for phone-splosions.


A teardown revealed that the battery housing was dangerously small. Image courtesy of Instrumental

Now, you're probably wondering, if battery swelling is common knowledge, why did Samsung proceed with such a dangerous design? The folks at Instrumental were curious as well.

“Samsung engineers are smart. Why would they design it like this?” - Samuel Weiss, CTO of Instrumental

After all, up until now, Samsung has had a good track record of solid designs for mobile devices. My Galaxy S6 has been working fine... And it's not like they're trying to jump on the latest trend of maximizing profit in a short amount of time like the obscure manufacturers of hoverboards all over the world (and yes, we are aware that they don't actually hover).

When the race to the market precipitates cut corners in designs with large lithium ion batteries—especially in parts of the world with little or no safety regulations for electronics—the resulting explosions aren't all that surprising. But what if Samsung's engineers were put in a position not so different from the engineers riding the hoverboard craze?


Member flaming hoverboards? Courtesy of Board Emporium

The Dangers of "Aggressive Design"

And how would Samsung's engineers be put in a similar position to hoverboard designers? The need to release products on schedule.

In this case, Samsung, locked in a perpetual battle for smartphone releases with Apple, was dead set on releasing the Note 7 before Apple released the iPhone 7. And, in the end, the Note 7 beat the iPhone 7 to market—but at the cost of not addressing a major design flaw.

Naturally, Samsung hasn't released details on the scenario, but I'm inclined to agree with Anna Shedletsky's analysis that Samsung's engineers were aware of this flaw, but the company decided to proceed with the release schedule anyway. Pressure to keep up with Apple in a brand war likely caused Samsung to release a phone that wasn't ready. Ironically, there have been rumors of iPhone 7's bursting into flames as well... perhaps these grueling release schedules aren't so good for the industry?

Samsung is launching a formal investigation to determine the cause of Note 7 explosions, but whether or not they actually release their real findings publicly is another story. There will likely always be some mystery surrounding the Note 7, so I don't expect stories and conspiracy theories to stop circulating the internet anytime soon.

Personally, I hope these events change the culture of electronics manufacturers for the better. This seems like a classic case of investors overriding the advice of engineers, and this time it cost Samsung $10 billion. Hopefully, in the future, electronics manufacturers like Samsung will take their engineers' input more seriously.

  • tweeker December 23, 2016

    The very FIRST step in troubleshooting any problem is to first establish blame….

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    • tim yb December 24, 2016
      Haha! Sad but true sometimes. That reminds me of a meme:
      Like. Reply
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    bugmenot12 December 23, 2016

    They have updated their FA and included a much better picture showing the issue (as well as a good explanation of their method)

    A prismatic battery, like that used in the Note, expands primarily if not entirely in the Z-direction.

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