Explosive yet oh-so necessary, Lithium-ion batteries reign in our electronic universe. Still, ask most people, average user and IT-enthusiasts alike, and they can’t tell you much about how these volatile creatures work or should be handled. In this three-part series we will explain how the battery works, how it shouldn’t be treated and how you can extend your battery life.

Should the battery be removed when the device is plugged into the mains? Can I properly recharge a battery that loses its charge after 20 minutes? Must it be completely discharged and especially, how to obtain those precious extra minutes on my laptop?

Whilst we will approach this subject concentrating on Lithium-ion batteries and laptop batteries, certain paragraphs of this first article can be applied to other electronic devices. In fact, Lithium–ion batteries are taking the world by storm (2 billion cells are produced each year) and so knowing how to handle them will soon be good knowledge for us all to have.

Inside a Li-ion battery

The first undertakings started in 1912 and are attributed to the American chemist Gilbert Newton Lewis. The first lithium batteries appeared in the 70s and the first attempts at rechargeable batteries appeared in the 80s. The obstacles that this technology imposed were overcome by Bell Labs.

Some of these obstacles included the instability of the lithium during the charging of the batteries. Professor John Goodenough and his team from Oxford University are responsible for the advances that allowed the commercialisation of this battery by Sony in 1991.

Anode cathode and more

A battery is composed of several elements. First we have the accumulators that store up the energy. They are generally (but not always) rigid cylinders (that look like traditional batteries), as they are cheap to manufacture, offer a good density, a good resistance to the internal pressure and are mechanically stable. You often hear of battery with 6 or 9 cells. An accumulator corresponds to a cell. So a 6 cell battery contains 6 accumulators.

Safety

The cell is composed of three main elements: the anode (negative electrode), the cathode (positive electrode) and of polyethylene or polypropylene layers which separate the two electrodes. These layers contain pores that have the property of closing from 130 degrees C with the aim of stopping any chemical reactions that would take place if the battery overheated.

The manufacturers also include various elements assuring the safety of the accumulators, such as a membrane which breaks down when the internal pressure becomes too high. When it breaks down, the cell works as an open circuit which should then, in principle, reduce the pressure. If this is not sufficient, there is a valve which opens to avoid the cylinder cracking.

When manufacturing batteries, the manufacturer places a PTC (Positive Temperature Coefficient) under the positive end of the battery. It is theoretically impossible to remove a PTC without destroying the battery first. Its function is to react to a rise of temperature; and when it reaches the threshold at which it is programmed to respond at, it reduces or stops the flow of the current in order to lower the temperature.

Lithium-ion batteries also possess a waterproof joint to avoid any leaks. In spite of all these security measures, the Li-ion accumulators are still dangerous, as the Sony setbacks [AKA The Exploding Laptop Fiasco –Ed] have shown. Without being paranoid, these accumulators nevertheless demand a certain vigilance while manufacturing and manipulating the battery.