29/09/2017

Batteries, Why Aren’t They Getting Better?

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29.09.2017,

 

Batteries have been around long before we had any practical use for them. Great minds like Benjamin Franklin have been intrigued by how some materials could conduct energy better than others and how some acids had weird, unknown reactions when in contact with metals. At that time, there wasn’t even a notion that this energy could be stored for future use. 

The History of Batteries

The first ‘real’ battery was introduced in 1800 by Alessandro Volta. He piled up a stack of silver, zinc and cloth soaked with salt-water which he called the Volta-Pile (which is why we measure battery energy by Volts). This primitive example of a battery inspired a whole century of scientists to experiment with its application and production. Waldemar Jungner introduced the first non-acid, alkaline battery in 1899, which uses the same ingredients (zinc and manganese dioxide) as the batteries we use today, but in a ‘wet’ and basic form. They were huge, impractical and didn’t keep their charge for long.

It was only in 1959 that Alkaline batteries became the reliable power source that they are now. Think of your AAA’s or 4.5 Volt’s readily available in stores. Though some Alkaline batteries can be recharged, it is far from the ideal battery. On its best day it can be charged ten times at most, on its worst it will rupture and leak corroding liquid.

Then came the commercial use of Lithium-ion batteries in 1991 by Sony, which were originally invented in 1980. This rechargeable battery is great for carry-on devices, since it can be manufactured into a long and flat form to fit its device. To this day they charge everything, from laptops to smart-phones. If you are carrying an Iphone, Li-Ion is what keeps it running. Since 1991, there have been other batteries on the market (Lithium-Polymer, Nickel-Metal Hydride, etc.), but these have not overtaken the Lithium-Ions. It seems peculiar that technology has changed so much since the 90’s, but the batteries charging all that tech hasn’t. You can hear people criticizing smartphone companies on how their old 2000’ Nokias could be on standby for 10 days without charging and that their modern Iphones can’t even make it through one day. This is because compared to other advancements, batteries are severely lacking. Look at the graph below, where battery density is compared to iPhone speed.

Batteries and Moore’s Law 

In our next article we talk about Moore’s law, and how it influences the trend in improvement for computer processors. This is what Fred Schlachter, an expert on this subject, has to say about this: “there is no Moore’s Law for batteries. The reason there is a Moore’s Law for computer processors is that electrons are small and they do not take up space on a chip. Chip performance is limited by the lithography technology used to fabricate the chips; as lithography improves ever smaller features can be made on processors. Batteries are not like this. Ions, which transfer charge in batteries, are large, and they take up space, as do anodes, cathodes, and electrolytes. A D-cell battery stores more energy than an AA-cell. Potentials in a battery are dictated by the relevant chemical reactions, thus limiting eventual battery performance. Significant improvement in battery capacity can only be made by changing to a different chemistry.

Changing Chemistry

Since the invention of the Lithium-Ion battery there have been many tweaks, like changing the consistency of the electrolyte-fluid, which makes sure the charged particles can move around. This method extents the battery life-cycle, but isn’t the big break-through that everyone is hoping for. It is very likely it is going to take many years to find a better combination than Lithium-Ion. The next big battery innovation will probably be something unexpected, like replacing the lithium with magnesium or sodium, or batteries made from molten aluminum, or filled with silicon. Or maybe something completely different! 

Currently, one of the most ambitious projects is to create practical radioisotope thermoelectric generator, or better known as the Atomic Battery, that uses the decay of radioactive material to generate electricity. You heard it right; a radioactive cell powering your phone, flashlight or laptop (good luck trying to get that through airport security). Radioisotope generators aren’t a new concept, but quite a few universities and research institutions are interested in making them more compact, safer and cheaper. Safety and costs seem to be the biggest concern at the moment. The Beta-rays, which can cause sterilization and cancer, can be stopped by a thin-piece of aluminum, but it isn’t considered safe by a long shot. As for price, radioactive materials are famously expensive and it wouldn’t be viable to create these super batteries for many years. But, if they would work the way the scientists are predicting it to, this kind of battery could hold energy for 10 to 20 years. Just take a second and think about not having to plug in your smart-phone for 10 years…

There are many ideas and theories about what the next big thing is, but no one knows for certain what the future will bring. Remember, mankind could never imagine a battery in the first place, so is it too far-fetched to think we could be carrying a small power-plant in our pockets?

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