September 29, 2017

Batteries, why aren’t they getting better?

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Batteries have been around long before we had any practical use for them (click here to find out!) , an interesting gimmick at most, 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 and used later.

The first publishing of the ‘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 the french word for battery is pile, and why we measure battery energy by Volts). This primitive example of an battery inspired a whole century of scientists to experiment with it’s application and production. Waldemar Jungner introduced the first non-acid, alkaline battery in 1899, which use the same ingredients (zinc and manganese dioxide) as the batteries we use today, just 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 it’s best day they can be charged 10 times at most, on it’s worst it will rupture and leak corroding liquid.

Then came the commercial use of Lithium-ion batteries in 1991 by Sony (originally invented in 1980). This rechargeable battery is great for carry-on devices since it could be manufactured into a long and flat form to fit it’s 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-Ion’s. 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 Smart-phone companies on how their old 2000’ Nokia’s could be on standby for 10 days without charging and that their modern Iphone’s can’t make it through one day. This is because compared to other advancements batteries are severely lacking. Just look at the graph below, where battery density is compared to Iphone speed.

In an earlier article we talked 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.”

But what does it mean to change this 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 where everyone one is hoping for. It is very likely it’s going to take years and 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. Batteries made from molten aluminum or filled with silicon. Or maybe something even wilder…

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, safe and cheaper. Safety and price are 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 still aren’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 projecting 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… Nice.

There are many ideas and theories about what the next big thing is (try googling battery innovations and look for yourself), 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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