Beginners Guide to Battery Technology

Batteries used to be seen as the little sticks that powered your remote control or flashlight. Nowadays, they’re in basically everything we use from our laptops to our smartphones and even our cars thanks to a certain Elon Musk.

Of course, despite their newfound omnipresence, many people still don’t grasp the finer nuances of how batteries work and what the technology is built around. This article is going to demystify the batteries that keep our world working 24/7.

The basics of batteries

Papers on cutting-edge battery innovations can give anyone without a chemistry Ph.D. a headache which is why understanding the basics is so important. Lithium-ion batteries are the most popular type, and you’ll find these in the vast majority of portable electronics.

Lithium-ion batteries are made up of a cathode, anode, separator, electrolyte, negative current, and positive current. The cathode and anode make up the respective ‘ends’ of the battery. During charging, the electrolyte carries the lithium ions between the two ends of the battery.

Infographic: how lithium ion batteries work

This is, in a nutshell, how energy is stored in a battery for long periods of time after the initial charge. Anyone with a smartphone knows that, when not in use, their battery can last for an impressive amount of time.

Why is lithium-ion so popular?

You might be wondering why lithium-ion batteries have become the industry standard. The main reason is that they’re one of the most efficient solutions and also one of the lightest. This makes them ideal for handheld electronics.

Although, there are still limits to the amount of power it can store due to its finite energy density. The last thing you want to do is push it too hard and overcharge the battery. That’s become far rarer thanks to smart charging controls in smartphones and other devices, but it still happens.

Potential risks and dangers

Batteries have grown in safety over the past decades. In fact, it’s amazing to see how far they’ve come. That being said, they’re not completely safe in every situation. If the electrodes in the battery contact each other due to a faulty separator, then the battery can rapidly heat up.

Because liquid electrolytes are extremely flammable, it’s not hard to see how exploding battery incidents can happen. This was the case with Samsung’s Note 7 that became notorious for its spontaneously combusting batteries.

It didn’t help that the separators in those phone batteries were far too thin to be safe for consumer use. Whether it’s an exploding smartphone or a crashed electric car, the culprit is usually thermal runaway issues.

The RC champion: lithium-polymer

While there’s no question that lithium-ion batteries are the leading option, they’re not the only solution currently in widespread use. Lithium-polymer, also known as Li-Po, is ubiquitous in the radio-control hobby space as their lightweight construction makes them the ideal candidate.

Lithium-polymer batteries are safer than lithium-ion and able to hold a charge for longer. That may make you wonder why they haven’t become the go-to option for smartphone manufacturers. The boundary to widespread adoption, in this case, is cost.

Lithium Ion vs. Lithium Polymer Batteries
Lithium Ion vs. Lithium Polymer Batteries

Some estimates show that they’re 30% more expensive to manufacture in comparison to lithium-ion. This could drive the price up, thus making certain smartphone models less accessible to consumers on the lower ends of the market.

That’s why smartphone manufacturers haven’t been able to justify the switch to Li-Po in most of their models. Certain flagships like the Samsung Galaxy S20, however, have already been able to switch thanks to their premium price point.

It’s not too surprising that Samsung is willing to pay extra to make us forget the Note 7 crisis.

Draining and overcharging

Contrary to popular belief, letting your battery fully drain is actually detrimental to its long-term health. If you discharge the cells below their lowest voltage limit, then copper dendrites could form. These dendrites will reduce the total capacity or even short circuit the cell altogether at times.

Overcharging is also detrimental but for a different reason. When you overcharge the cell, the anode will suffer damage due to lithium dendrites. Rather than reducing capacity and lifespan, this can lead to a short circuit or full thermal runaway.

Smoke and flames are the most characteristic signs of an overcharged battery.

Charging speed

You don’t have to be familiar with the technology behind batteries to notice the trend towards faster charging in the smartphone world. After all, no one has the time to wait for two hours while their smartphone sluggishly charges up.

However, you shouldn’t charge lithium cells too quickly as this can lead to a whole slew of problems. Smartphone fast chargers will generally slow down before any issues occur, but it’s still something to take note of. Furthermore, avoid unreputable third-party fast chargers.

Ambient temperature

Ambient temperature is another determining factor in battery technology. Engineers are always trying to find ways to make batteries more resilient to rapid changes in temperature, but they haven’t been able to completely alleviate the issue.

When lithium batteries are in an ambient temperature below freezing, plenty of issues can start to arise. This is even more troublesome if the battery was fully charged when it was exposed to this subzero environment.

Trying to charge a battery below zero degrees celsius is ill-advised as it can lead to significant damage or short circuit the cell. If you’re between zero and five degrees Celsius, then it’s possible to charge a lithium battery but you must do so slowly.

The inverse is also true as trying to charge batteries at temperatures above 45 degrees Celsius will lead to damage, albeit not as significant as subzero damage provided you’re not too far over the 45-degree mark.


As you can see, batteries are not so complicated when you break them down into their core parts and understand how they function at an elementary level. As battery innovation continues, it’s exciting to imagine what the next generation of cells may look like!


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