Apple had said that the issue affects a very small number of units. The replacement batteries were offered only for phones manufactured between September and October 2015. The association disagrees with Apple on the number of devices affected, and has asked Apple to make the process easier for its customers. “We looked for any other factors that could cause an iPhone to shut down unexpectedly. After intensive investigations, no new factors have been identified,” Apple wrote in a new statement issued Friday on its Chinese language website.
They also explained what it happens: “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. As a result, these batteries degrade faster than a normal battery and cause unexpected shutdowns to occur. It’s important to note, this is not a safety issue.” They specified more, that an iPhone is actually designed to shut down automatically under certain conditions, such as extremely cold temperature. to protect the device.