Without electricity, modern life would be impossible. And the same can be said for a specific kind of electricity: the kind that comes from batteries. Most of the appliances we rely on (like phones) don’t draw power directly from the wall but store it for later use.
But exactly how did this technology come about, and assume such a central role in our lives?
Basic Battery Chemistry
In every electrochemical battery, we find two different metal plates suspended in a chemical called an electrolyte. One of the metals loses electrons to the other, which causes it to develop a positive charge. When the two metals are connected via a conductive path, electrons are free to travel along that path.
Batteries come in many different types.
Lithium-ion batteries are favored by power tool and electric car manufacturers. They offer very high energy density, which means that they can offer the power needed for these appliances without compromising on weight.
Nickel-metal hydride batteries offer greater energy density than their cousins, Nickel-Cadmium. Consequently, they’re favored by smartphone and laptop producers, who need as much power as possible for as little weight. NiCd batteries tend to be used in situations where longevity, discharge rate, and price are all consequential, but the toxins found in these batteries make them difficult to dispose of responsibly.
Battery Components and Construction
Let’s address the underlying chemistry in greater detail. Those metal plates we discussed have names: electrodes. The negatively charged electrode is known as the anode, while the positively-charged one is known as the cathode.
Of course, another vital component of any battery is the casing. It’s this outer shell that prevents harmful chemicals from leaking out and causing harm. Battery holders also play an important role in many devices – especially those that are likely to move around.
Battery Sizes and Standards
Batteries come in a range of sizes. Near the smaller end of the scale, we might find AAA batteries; at the larger end, we find D-sized batteries, which are used in flashlights. Of course, not all batteries are cylindrical.
Batteries must obey standards set out by the International Electrotechnical Commission (the IEC), and the International Organization for Standardization (ISO). This helps to ensure that your remote doesn’t produce smoke and a bad smell because the batteries are of the wrong voltage.
Battery Capacity and Voltage
Batteries come in different voltages. You can think of this as the amount of potential, or the ‘push’ being given by the battery. This needs to be matched between the appliance and the battery. On the other hand, there’s the amperage, which refers to the speed at which those electrons flow. Appliances might vary from moment to moment in the amount of current being drawn.
The ability of the battery to satisfy the demand is measured in milli-amp-hours (or mAh). The larger the number, the greater the capacity.
Charging and Discharging
You can think of a rechargeable battery as a little bit like a parking lot. When there are lots of spaces for the electrons to attach to, those electrons will settle quickly, and a charge will develop rapidly. When the battery is nearly full, the electrons will have to bounce around for longer. Thus, the last 20% of a battery’s charge will tend to take a long time to fill.
We should also consider the role of factors like temperature. When it’s cold, batteries both charge and discharge more slowly – which is why modern electric cars often allow us to ‘precondition’ (that is, warm up) before departure.
Battery Maintenance Tips
So, how do we get the best from our batteries? There are a few things to consider.
First, store batteries at room temperature, and away from sunlight. The changing temperatures in your garage will harm the battery in the long term. The same goes for moisture: keep those contacts dry!
Avoid storing batteries in metal places where the contacts could be short. This will cause the battery to discharge rapidly, which could pose a risk.
Finally, batteries should be responsibly disposed of. Recycling and sustainability have come a long way in this area – but battery users must get their batteries recycled.