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 2016-12-23

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

  • bugmenot12 2016-12-23

    They have updated their FA and included a much better picture showing the issue (as well as a good explanation of their method) https://static1.squarespace.com/static/57bf598629687fe4f8dc7f3f/t/584ca10ebe6594f67561b7ae/1481416978451/?format=1000w

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

  • uwezi 2016-12-23

    I could imagine that they will identify and fire the responsible engineer and the manager pointing out the poor guy will get a bonus… And this is then meant to establish an example that the remaining fewer engineers do a better job in shorter time on a smaller budget next time… ;(

    • tim yb 2016-12-24

      Hopefully not, but it wouldn’t surprise me. I imagine the situation was like in sci-fi movies where the scientist or engineer keeps saying “It’s not ready” but their corporate overseer makes them release what they were developing anyway.

  • bobcov 2016-12-23

    Would be nice if they measured the dimensions of the battery space in another Samsung phone with a similar size battery. That would tend to strengthen an already strong case.

  • KLRico 2016-12-23

    Shouldn’t it have been an easy fix to just redesign the battery?

    • tim yb 2016-12-24

      From what I understand of the whole situation, it sounds like that was an option. It would have been relatively easy, but they didn’t want to sacrifice battery life, charging time, or miss their release date.

      If you check out Kenneth Bouchard’s comment below, he gives some good insight on battery testing!

  • Parkera 2016-12-23

    “Hopefully, in the future, electronics manufacturers like Samsung will take their engineers’ input more seriously.”
    Just like the auto industry does.

  • Nigon 2016-12-23

    They should of put a ruler next to their measurements, to me the clearance looks to be very close to 1.0 mm , way bigger than their 0.1 , 0.3 and 0.5 mm readings.

  • Kenneth Bouchard 2016-12-23

    Well my thoughts are it is not a physical compartment design flaw. I say this because most cell phones the battery compartment is designed to precisely fit the battery.
    My concern in having seen how batteries react to charging, is they failed to design good firmware.

    To see the problem, you need to do 2 things. 1 charge the phone with the battery out of the phone, using a test cable rig, that allows you to measure what is going on by taking the battery and running it flat and charging it, and observe by time how much it 1: Heats up during a full charge. 2: How hot is the compartment getting by putting the phone into its least conservative mode, I.E. a stress test. Doing all that OFF the charger, and then doing it ON the charger, for at least 10 cycles of discharge and charge. 

    My thought is that the materials used in the design of the battery were too thin. If you tear apart the faulty batteries, you find inside lots of very thin plastic and paper is used as insulating materials between the cells. It is the cell construction, that if overheated, causes the cells to short out, break down, and then explode because your dumping them radidly that leads to fire and then explosion. Then the other factor would be how easily can the protective material wear a hole in it due to slight bending. The cells have some give factor in them that allows bending and crushing. While the cell phone generally is a solid compartment, as stated the package is in a very tight and cramped space. Any part of the battery that is too close to a sharp point, such as a screw, would be the weak link in the chain. The final factor is the firmware and heat detection of the battery. Modern batteries have what is called a thermal resistor some even a chip, that monitors heat and current of the charge process. The idea of course is to prevent the battery to heat up, by reducing charge current in real time. If a cell overheats it is going to hopefully cause the charge circuits to stop long before the battery reaches critical temperature. Its a tradeoff of charge time, vs heat. The faster you attempt to charge the battery, the hotter it will get, and of course the higher the risk of explosion.  But of course manufacturers, want to offer the consumer as short a charge time as possible, so that they can revive the phone in the car, in the 15 minute drive to work. Like all other worldly things, time is made too short on the charge side, result in overheating, smoke, sparks, fire, Kaboom. Fun to do in a laboratory under controlled conditions, but not in your back pocket.

  • Kenneth Bouchard 2016-12-23

    A recall like those for cars, is always a problem if it involves safety. The problem is 2 fold. A Cell phone being a product that the consumer relies on if for business or otherwise, the recall fails. Some would ignore the recall because it is inconvenient for them to have to take the phone back to trade it in, spending time to have to trade out the phone and either lose their information because they did not have time to backup the phone to the clouds etc. Time for the carrier to port their number over to the new phone, and time to just get to the carrier. So in the meantime, they ignore the recall and walk around with a bomb in their pocket. And they well may be the lucky few that do not encounter any problem. And just the time it does take the phone to transfer all your data while you need all of the data right now. Such a situation also causes mass panic, and stress, to find time to get your phone exchanged, the panic causes many to want to return the phone, get their money back, and go shop for a different brand of phone (I phone or otherwise). Some will remain faithful, and others may not be offered any choice but to trade in the phone for the same exact model. Then being such a large recall, how can Samsung deal with the massive number of phones yanked off the shelves, factory re certify them, and deal with the massive amount of returned phones? Few also would be willing to wait any length of time for a replacement. So the whole ball of wax cascades out of control for a short period of time. Basically nobody wins.

  • DakLak 2017-01-31

    My employer has nine of these units, after a mutually agreed Court Order awarded us costs against Samsung (defective product claim) and the continued use of the handsets, less the batteries. They are used for MESH radio communications (think SERVAL [App]) between different parts of our work area.

    I took the units to our Samsung service centre for the technician to remove the batteries - a one hour operation.

    Unbelievably the battery is sandwiched between two PCBs (front and rear) and accessed only after a tricky procedure involving the removal of the rear PCB. Whilst the packaging and electronics design is of Samsung’s usual high standard, the fact that the battery is buried deep within the electronics is stunningly dumb.

    All for the sake of ‘thin’.

    I would never personally buy ANY electronics where the battery can’t be changed or where there is no audio jack.