Samsung's report into its exploding Galaxy Note7 and the unprecedented worldwide recall it caused has just been released, and there's one obvious difference it will make for the future phones you buy: they'll have an internal rollcage protecting the battery even when dropped. That means your next Samsung might be thicker, and definitely sturdier, than the one it's replacing.
Thinner batteries with higher energy density were essentially responsible for the Note7's high-profile failures, which led to two separate recalls and a complete discontinuation of the phone. Two distinct issues with the two different suppliers that delivered Samsung batteries for the Note7 caused issues, but both were related to the physical dimensions and high energy potential of the Note7's 3500mAh cell.
Because the batteries were thinner, and used new design and construction techniques to achieve both the thinner dimensions and comparatively high energy density (versus older Note devices), failures in the protective coating between negative and positive electrodes led to short circuits within the cells at a much higher rate than other lithium-ion batteries.
Combined with a high energy density and high(er) temperatures — although within Samsung's design specifications — high heat when the Note7 was charging to near full capacity meant that some phones' batteries triggered a thermal runaway, a cascading series of battery cell failures that lead to overheating and fire.
The one major thing that Samsung's president of mobile business DJ Koh pointed to as a learning that the company will implement on future Samsung phones, though, is unrelated to the battery itself. "A new hardware design means more space around the battery to accommodate a new bracket design to protect against force, even when the device is dropped," was mentioned by Koh at the Note7 press conference.
Samsung also has new quality control measures in place, it says, to ensure the battery issues that caused the Note7's unexpected fires will not happen again:
And here's an infographic developed by the company on what went wrong: