Is the device in my pocket just one fast charge away from exploding? Probably not, and here’s why.
As long as we’ve had smartphones, we’ve wanted to charge them faster. Each year, the newest phones come out with incredible advancements in fast charging technology. Where a 30W charger used to feel incredibly fast to me, it’s now a pretty standard charging speed, replaced by blistering figures over 100W in the fastest phones. I remember a phone from a few years back actually offered 150W charging, capable of charging the phone to 50% in just five minutes. The iPhone 17 Pro Max’s 40W charger can reach a 50% charge in 20 minutes.
But as phone makers experiment with fast charging, I’ve noticed an uptick in concern about overheating and battery damage. Is the device in my pocket just one fast charge away from exploding? In short: probably not, and here’s why.Why Phone Batteries Lose Charge Capacity Over Time
Ever wonder how a phone actually charges? Lithium-ion batteries (the type used in iPhone and Android devices) have two layers—lithium cobalt oxide and graphite. When lithium ions move from the graphite layer to the lithium cobalt layer through an electrolyte solution, electrons get released. When you charge the battery, the ions move back in the other direction and are stored to be released later, when you power on and use your device.
That release of energy creates the heat you may feel radiating from the back of your phone after a long charging session or heavy use. And, yes, that heat can damage the battery in the long term. However, I feel like I need to stress that li-ion batteries have become smaller and more efficient over the years. They can handle more charge cycles—going from depleted, to full, and back down again—before they begin to lose their charge capacity. For a visual breakdown, I think the below video from tech YouTube channel Branch Education offers a helpful representation.
As your smartphone goes through charge cycle after charge cycle, it degrades naturally. One reason is the electrolyte solution within the battery. Over time, the salts in the solution can crystalize, forming solids that block the transmission of ions through the solution.
