I was planning to use my old iPhone 3GS for weekend project but I discovered that the screen was popped out and the back was bulging, I took it apart and this
My DIY iPhone Battery Replacement Was Easy. Here's What I Did. - CNET
Third-Generation iPhone SE Teardown Reveals Larger Battery Capacity and Snapdragon X57 Modem - MacRumors
Apple adds the battery percentage icon back in the latest iOS beta | TechCrunch