BATTERY TECHNOLOGY EXPLAINED

We all know how to use a rechargeable battery. You plug it into the mains to charge it up; then you can use that charge to power a phone, laptop or other device until it runs out. But what’s actually happening inside the battery? And how do you keep a modern lithium battery working safely and efficiently for as long as possible? Here’s what you need to know about those little power packs that keep everything ticking over.

What’s the charge?

As a rule it’s best to keep liquids well away from your electronic devices, but most batteries actually contain a liquid substance called an electrolyte. This is the chemical that stores the battery’s charge, and it’s internally divided into two compartments by a thin physical separator.

We won’t get into the details of the chemistry here, but simply put, charging the battery pushes positively charged ions through the separator, from one side of the electrolyte to the other. When the current stops, the charge can’t pass back across the separator, so the battery ends up with one positively charged end and one negatively charged end. These opposing ends are connected to two external terminals – the anode on the negatively charged side and the cathode on the positively charged side – and when these are connected to an