Slashdot Mirror
Engineers Explain Why the Galaxy Note 7 Caught Fire (digitaltrends.com)
Engineers with manufacturing technology company Instrumental tore apart a Galaxy Note 7 to try and figure out what may have caused some devices to overheat and explode, causing Samsung to recall and eventually cancel all Galaxy Note 7 devices. In their damning new report, the engineers discovered the root of the problem appears to be that the battery is too tightly packed inside the body of the Note 7. Digital Trends reports: They discovered the battery was so tightly packed inside the Galaxy Note 7's body that any pressure from battery expansion, or stress on the body itself, may squeeze together layers inside the battery that are never supposed to touch -- with explosive results. Batteries swell up under normal use, and we place stress on a phone's body by putting it our pocket and sitting down, or if it's dropped. Tolerances for battery expansion are built into a smartphone during design, and Instrumental notes Samsung used "a super-aggressive manufacturing process to maximize capacity." In other words, the Galaxy Note 7 was designed to be as thin and sleek as possible, while containing the maximum battery capacity for long use, thereby better competing against rival devices such as the iPhone 7 Plus and improving on previous Note models. The report speculates that any pressure placed on the battery in its confined space may have squeezed together positive and negative layers inside the cell itself, which were thinner than usual in the Note 7's battery already, causing them to touch, heat up, and eventually in some cases, catch fire. Delving deeper into the design, the engineers say the space above a battery inside a device needs a "ceiling" that equates to approximately 10 percent of the overall thickness. The Galaxy Note 7 should have had a 0.5mm ceiling; it had none.
This is bad. Very bad. If substantiated, the lawsuits against Samsung are going to be epic.
Theory sounds plausible but doesn't carry much weight without experiments that demonstrate the internal battery components actually making contact as a result of the factors they describe.
1. Design ultra-thin phone
2. Disregard warnings from engineers
3. Profits!
Correction, I meant "physical engineer". But if you were a psychical engineer, you'd know that already.
Table-ized A.I.
>"...what may have caused some devices to overheat and explode,..."
To my knowledge, NONE of them "exploded". Those that had actual problems had overheating which led to a fire. That is not an "explosion". That word was used by the media to stir up tons of inaccurate hype.
>"...causing them to touch, heat up, and eventually in some cases, catch fire."
Exactly.
If only Samsung had brought in Mr. Whipple to help educate the public.
They were tested using Android Lollypop, its only when they installed Marshmallow that it became an issue.
What about stop making stuff super thin?
Hopefully this provides some motivation to stop equating thin with better.
Nah, who am I kidding, people are stupid.
As in most cases, going to extremes is rarely a good thing.
Not just minimum. Below minimum or none at all.
Intolerant tolerances will not be tolerated!
You have the right to remain sentient. If you give up the right to remain sentient, you will be elected to public office
Testing probably missed it because even with the thinner design it was a rare occurrence. Failures in 1 out of 200,000 phones is a big deal when you ship enough, but not so easily found in lab sampling. That said, the testing should mimic conditions beyond any expected in normal use and have a higher failure rate.
Air _is_ an insulator. Its the same idea as double pane windows.
Double glazed windows have a vacuum (or sometimes a noble gas) between the panes. If air gets in between the panes condensation starts to appear in cold weather. If that happens the window has to be replaced; they can't be repaired economically.
If God forks the Universe every time you roll a die, he'd better have a damned good memory.
If they found the problem, it means that they can reproduce it. They were entirely unable to make their test unit fail due to the tight fit, nor were they able to observe that an increase in pressure of a phone in the off condition (under which at least one of the fires occurred in the v2 Note 7) *led to* a runaway thermal condition.
They're basically just speculating because they are looking for some clicks. This is about as conclusive proof as Trump has of 3 million illegals voting in California.
Is it just my observation, or are there way too many stupid people in the world?
Korean person: "No-no! Americans VERY heavy!"
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
If you're talking about things that happen with p < 10^-5 you can can't test to any kind of reasonable confidence level. Engineers have to use the collective experience of the profession as a whole as a guide, in addition to actual testing.
Since phone design is interdisciplinary -- involving marketing, industrial design and engineering -- engineers will just have to push back when the designers and marketers try to take that half millimeter away. This case will be a touchstone for future generations of EEs, the way the Tacoma Narrows Bridge is for civil engineers and Therac-25 is for software engineers.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Having sat through management/engineer meetings it went like this:
Manager: Why are you wasting 10% there?
Engineer: We need design margin for tolerance stackup and thermal expansion.
Manager: But we'll lose sales! (in his head: "I'll lose my bonus!")
Engineer: We need design margin or there is a chance that some of the batteries could catch on fire.
Manager: So only a chance? Make the battery 10% bigger and stop complaining.
Engineers are measured and cautious in their statements. They talk in statistics, numbers, and probabilities, all of which have been lobotomized out of mid-level managers.
Software "engineers" at best.
This is the company in question. https://www.instrumental.ai/te...
It's a small startup of 9 people with no history. None of the people are even listed as mechanical engineers. They're all software engineers (which isn't a recognized profession, by the way) and business people. Not a one among them has the authority to make any claims about the Note 7. None of them have the actual experience with the Note 7 to do so either - they had a single sample that they couldn't actually do anything with other than write the blog post and fish it out to tech sites for hits and to get their name out there.
People should bare in mind that this is at most an educated guess made by disassembling a single unit and speculating about limits of current tech battery design.
They were not hired by Samsung, they are not an official body of investigation, and they didn't have access to anything in the design in manufacturing process.
It's quite possible that they are right, but they are not explaining anything there, just speculating.
Now, it'd be extremely sad if the Note 7 was killed because of such a design oversight, because quite honestly, that's borderline amateurish. It could happen, as similar problems happen in most brands. Just that Samsung made the omission in the worst component possible.
We have examples of problems in antennas, cameras, lenses, connectors, shoddy speakers, crappy GPS chips, poor materials used in bits and pieces, among several other stuff... the difference is that if you have something wrong with battery, the consequences might not be only working poorly, ending up in glitches and whatnot. The consequence might be an explosion. Which is probably the worst thing hardware can do. :P
Anyways, the device is as dead as it can be. Which is plenty bad, because it'd probably be a best seller otherwise. Hopefully though, the lesson is learned by all manufacturers. It simply isn't worth sacrificing battery security to make the device thinner, or to shove extra mAh in there.
The worst part is that I can bet all you want that fans of the Note line would definitely not be bothered much with having a smaller battery or a slightly thicker phone. It's all about the stylus and screen size.
Back to the topic, I'd wait for further investigation for a final conclusion. Disassembling a single device and taking guesses is not that much better from theories that have been thrown around so far.
...Dilbert quote.
I don't understand the obsession with thinness.
Ever since my phone was less than 4cm thick I have been quite happy. What is this need to keeping shaving millimeters off?
If I had a DeLorean... I would probably only drive it from time to time.
None of what you said has ANYTHING to do with what I wrote, nor what was in the article. Did YOU read the article, or did you just jump straight to the TEAM link at the top to "play the man, not the ball"?
This is the company in question. https://www.instrumental.ai/te...
It's a small startup of 9 people with no history. None of the people are even listed as mechanical engineers. They're all software engineers (which isn't a recognized profession, by the way) and business people. Not a one among them has the authority to make any claims about the Note 7.
Thanks for the link. Very helpful. If you read the article, you know that it says in the second paragraph (why don't I have to read beyond the first screen?):
We can use the link you provided to find out who "Sam and I" are, and with its helpful embedded linkedin links, find out what just how unqualified they are to comment on the Samsung phone:
Anna Shedletsky
Samuel Weiss
Oh dear. I certainly hope that those two experienced mechanical engineers spent more time examining the Note 7 problem than you spent attempting to trash their reputations. I guess Slashdot pest isn't a recognised profession either.
Double glazed windows have a vacuum (or sometimes a noble gas) between the panes.
Or dry air. There's no need to use anything other than air to avoid condensation. You just need to make sure the air is dry and the windows are sealed so humid air can't get in. I doubt many windows are vacuum-filled; that's just begging for trouble, and would also limit the size of panes. 15 pounds per square inch adds up to a lot of pressure very quickly.
Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
Double or triple pane windows usually have argon as the fill gas as both its higher molar mass and smaller molecular size than the diatomic major molecules in air increase its insulation ability because of reduced thermal conductivity. It's also naturally water free if provided from liquid argon which is generally available. FYI, the thermal conductivity of a gas is proportional to the square root of molar mass and inversely proportional to the square of the molecule's diameter. At least that's true for real gases at atmospheric pressure which behave nearly like ideal gases
In a time of universal deceit, telling the truth is a revolutionary act. George Orwell
Because unlike geeks who are often happy with purely functional devices, many consumers also want their phones to be sleek and stylish. And there are many, many more of them than there are of us. It's the same reason phones don't have SD cards or replaceable batteries anymore. We're no longer the target audience.
I've heard these people also tend to buy very expensive clothes that are no more functional than clothes that cost 1/10th the price. Crazy, huh?
Irony: Agile development has too much intertia to be abandoned now.
Phones have been sleek and stylish for years already.
Fashion isn't logical.
Irony: Agile development has too much intertia to be abandoned now.
On the other hand, you have EEs like me.
Engineering runs a spectrum. From near cookbook, long practiced, design processes owned by PEs to prototypes hacked up with three opamps, a FPGA, a breadboard and a coat hanger.
Design of consumer product batteries is 'near cookbook long practiced'.
Even I could do it. Samsung wouldn't have given me the authority to tell the PHB they _needed_ volume Y for X mWh. I guarantee there was an Engineer or ten that knew this was a bad idea, but couldn't penetrate the layers of management between him and the person dictating required features.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Looks like I made a politically incorrect joke and got someone offended.
What has the world become...
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
Engineers are basically people who keep saying "it can't be done in under budget and on time!" Which is why most companies now have products designed by marketing and sales. CEOs don't like workers who keep telling the truth.
It is, but not logical in that way. Fashion demonstrates that you can do something other people can't - whether it's spend more money, wear something that is inconvenient because you don't have to work, etc. What it's definitely not is about "getting something done efficiently". Quite the contrary, and hence the assumption of a lack of logic.
People perceive high-density products as high-quality, and low-density products as cheap plastic crap. Numerous products have included weights for this reason... take a look inside your mouse. People want their phones and laptops to be light so they don't have a brick in their pocket or backpack. Light * high density = low volume. They don't want to reduce the screen size, and bezels are already minimized, so the only option to reduce volume is to make it thin. Of course, once they make it thinner the advertising department will hype that feature, but the real driver is density.
Phones have been sleek and stylish for years already.
But this one is really hot off the shelves. An absolute blast to use.