Apple blames iPhone 6s battery problems on air exposure during manufacturing
Elaborating on an unfolding issue with iPhone 6s shutdowns, Apple on Friday linked the problem to gaffes during the manufacturing process.

"We found that a small number of iPhone 6s devices made in September and October 2015 contained a battery component that was exposed to controlled ambient air longer than it should have been before being assembled into battery packs," Apple wrote on its Chinese website. "As a result, these batteries degrade faster than a normal battery and cause unexpected shutdowns to occur."
The company insisted "this is not a safety issue," presumably concerned that people could draw comparisons with the Samsung Galaxy Note 7, which was taken off the market because of battery fires and explosions.
iPhones are designed to shut down automatically under some conditions to protect electronics from low voltage, Apple added.
Apple recently began a battery swap program, allowing owners of affected iPhone 6s units to get their device fixed for free, or a refund if they previously paid out-of-pocket. On Thursday, the company introduced a Web tool for checking for a qualifying serial number.

"We found that a small number of iPhone 6s devices made in September and October 2015 contained a battery component that was exposed to controlled ambient air longer than it should have been before being assembled into battery packs," Apple wrote on its Chinese website. "As a result, these batteries degrade faster than a normal battery and cause unexpected shutdowns to occur."
The company insisted "this is not a safety issue," presumably concerned that people could draw comparisons with the Samsung Galaxy Note 7, which was taken off the market because of battery fires and explosions.
iPhones are designed to shut down automatically under some conditions to protect electronics from low voltage, Apple added.
Apple recently began a battery swap program, allowing owners of affected iPhone 6s units to get their device fixed for free, or a refund if they previously paid out-of-pocket. On Thursday, the company introduced a Web tool for checking for a qualifying serial number.
Comments
Excess exposure to air. This not only demonstrates the complexity of working with the latest technologies, but also explains why copy-cat smartphones by companies that scrimp on engineering are often less reliable, less capable and possibly unsafe.
Or they know exactly what happened, but aren't saying because of embarrassment.
If you notice everything that goes into an iPhone probably has been played with in some manner for at least a year or two.
If manufacturing screws up, there isn't much Apple can do about it. Likewise if a batch of raw materials doesn't meet technical requirements.
That said, traceability has reached the highest levels ever in manufacturing and greatly helps to determine the units affected by any manufacturing problem.
What is curious about this case is that they have given a clear answer (putting the blame on the manufacturing process). Of course, that makes us ask why the problem wasn't detected earlier and remedied in situ. It was definitely logged clearly. Perhaps it was part of an automated process and just wasn't detected sooner or perhaps someone thought the impact wouldn't be so serious to the end user or, in a worst case scenario someone just ignored the issue hoping that the affected numbers of users would be so small as to be statistically insignificant.
Part of me thinks a new battery would be good to have; preventative maintenance should it develop problems later. But another part of me thinks "if it ain't broke...".
Hmmmm...
Worst case scenario you get a new battery to replace a year-old one. I'd do it. In fact I am doing it since I qualify, but my phone has shut down unexpectedly a small number of times (when around 15-20%).
Makes me think that they only recently discovered that the reported problems correlated with the air quality/air exposure data and determined the root cause.
The "exposure to air" could be anything from a container left unsealed too long between batches, shifts, etc. or a moron opening a door at the into a room at the wrong time. It's a quality control issue, ultimately.
The batteries are defective. Their capacities are probably greatly reduced. The cell voltage drops off so fast the phone can't calculate the remaining life before the phone just shuts down.