Assault on Battery: Charging explained

Charging explained

Millennial banter doesn’t often end up being a commentary on the tech scene-

“Got Juice?”

Smartphones have come a long way. From their first gigantic predecessors to their slim, foldable future, they’ve lost a lot of bulk and gained a lot of brains. While everything being fast, getting faster and racing to fastest, there’s one integral component that has been watching in silence. Not anymore.

Smartphone batteries have been worked on as long as smartphones themselves. Daft Punk would’ve been glad to see them getting bigger, better, faster and stronger. Most smartphones nowadays ship with highly efficient Lithium-Ion Batteries. These have enough capacity to power most people throughout their day. If tech stopped at “If it ain’t broke, don’t fix it!”, would we even bother to innovate?

Years ago, a device that can power itself wirelessly seemed like a concept out of Isaac Asimov’s science fiction. Today, it’s a magical reality. Fast charging has enabled us to get hours worth of usage within minutes of charging.

When you dig deeper, however, charging is a complicated mix of chemistry and physics, and each has its own set of limitations and incompatibilities. What makes it worse is that phone makers slap confusing labels on otherwise straightforward components.

Curious how your shiny new fast wireless charging phone’s battery works? Answers to all your questions ahead.

Battery Amplified

“Mitochondria is the powerhouse of the cell” is probably imprinted in your memory of elementary school. It’s the same with smartphone batteries

All batteries in electronics deliver power, working in more or less the same way.

Cells consist of two electrodes, positive or negative, and an electrolyte accelerates chemical reactions that convert compounds into new substances. Over time, ions — particles with some amount of charge (+ve or -ve) — form in the electrodes, driving a flow of electrons to an outer terminal and supplying your phone with a charge.

In regular, non-rechargeable batteries, these chemical reactions occur only once. In the rechargeable batteries that power smartphones, however, the reactions are “reversible.” When a battery discharges, the chemical reaction produces power, and when the battery gets connected to a power source to recharge, the chemical reaction absorbs electrical power.

Since we’ll be referring to volts, amps, and watts in the course of our discussion, here’s a refresher. Volts are a measure of voltage, amps are a measure of current, and watts are a measure of electrical power.

Batteries charge when a current is passed through them and while higher currents and greater voltages charge batteries faster, there’s an upper limit to what batteries can take without malfunctioning (or worse, exploding). The charge controller (IC) is a component that protects against spikes in current that may prove fatal to your phone battery

Plugged In

Unless you’re light years ahead with no batteries or are using a landline with wires, chances are your phone recharges via USB. Besides the fact that USB cables are ubiquitous these days, USB has a really well-managed, robust charging standard: the USB Power Delivery Specification.

The USB Implementers Forum has specified four types in total, one each for USBs 1.0, 2.0, 3.0, and 3.1. There’s also buzz about USB 4.0 on the horizon.

A typical USB 1.0 and 2.0 plug can deliver up to 5V/0.5A (2.5W).

Charging Cable

Lithium Bros

There are two types of batteries used majorly for smartphones: Lithium Ion and Lithium Polymer.

The former is the older and most popular technology for cell phone batteries. The only Li-Ion is their high cost of production. However, they can hold higher energy for the same area compared to Li-Polymer.

Li-ion and Li-Polymer batteries have the same chemical composition but differ in their heating tendencies. Lithium Ion batteries have an active protection circuit-basically an onboard lifeguard-that prevents the battery from getting too hot and perhaps even exploding into flames. Li-Poly batteries skip the active protection circuit, which is why they can be produced in sizes as small as a business card.

Which is better? There’s no absolute answer. Li-Ion holds more charge but takes a lot more room.

Li-Poly can be made really small but runs the risk of being a fire hazard if overheated.

Getting juiced up never felt better.

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