Super Capacitors, Batteries & The Electric Vehicle Revolution!


Car Batteries

During a technological revolution, change happens quickly. Today, we’re flooded by tech revolutions. Ther are so many it’s difficult to sort them all out. Our power grid is slowly going sustainable, everyone is adding power storage, and vehicles are transitioning from gasoline to electric. Batteries have become a key technology behind all of these revolutions. Every day you hear about some new kind of battery. There are endless stories about new and improved battery storage, lithium, and “rare earth” materials. Now we can add a new category of tech… supercapacitors.

We’re all familiar with capacitors. At a wedding, graduation, or wherever a professional photographer takes your picture with a flash, that whine coming from the camera between photos is the sound of a capacitor charging. The flash needs a big, quick burst of power. Batteries can hold more power, longer… but batteries can’t send out power as quickly as a capacitor. Batteries charge the capacitor and the capacitor blast out the power needed by the flash.

Capacitors can do some amazing things, things that batters are bad at. Capacitors charge VERY quickly. Small capacitors can handle vast amounts of power. And… this is BIG… they can charge and discharge over and over again. Lithium batteries can be recharged a few thousand times. Capacitors can be recharged a million times or more.

Batteries are one of the most expensive parts of an electric car. Batteries determine the distance you can drive. Every charge cycle deteriorates your battery just a little bit. As your car ages, it loses range. Electric cars are new and few, so we don’t have enough data, but a frequently driven car will certainly see a significant loss of range in 10 years. Batteries will be the first major component to require replacement, and it will cost thousands of dollars.

New Supercapacitors will not replace batteries, but they can supplement battery technology. How? Well, many electric cars have regenerative braking. Essentially, when you drive you use power from the battery to drive the electric motor. Regenerative brakes make power when they slow down your car. The more you use your brakes, the more electricity you generate. That electricity recharges your batteries.

Regenerative braking can be very effective, capturing as much as 60% of the power it takes to slow or stop your car. If your drive to work is highway only, with roads as flat as a pancake, you don’t do a lot of braking. But your daily drive has a lot of uphill and downhill driving, or mostly city driving (stopping and starting, traffic jams),  … then every tap of your brakes adds milage. For most drivers, regenerative brakes add a LOT of mileage.

Getting more range and “free” fuel IS great for consumers! But not so great for batteries. Remember, current batteries can only be recharged so many times before they deteriorate. But what if you put a supercapacitor between the brakes and the batteries? The supercapacitor soaks up all of the “micro-charges” from your brakes, and holds them for a few seconds or a few minutes, reducing the charge cycles for your batteries. Add some smart software to manage how often charges are sent back and forth, and your battery will work a lot longer!

This model might look very familiar. And it is! Supercapacitors provide a buffer for batteries. Electronics, especially computers, have used high-speed memory to buffer slower memory for years. Hard drives have a lot of capacity and are cheap, but are slower compared to (more expensive) solid-state drives (SSD). Virtually all hard drives use some form of solid-state memory as a buffer. There is a high probability that some bit of information that you just asked for, might be asked for again. Fetching data from solid-state memory is far faster than fetching it from a spinning disk.

In hard drives, “efficiency” is all about speed. In an electric car “efficiency” is about how much power they can store and how often they can be recharged. Batteries continue to become cheaper, with more recharge cycles. A car designed with a combination of batteries and supercapacitors might create a combination that provides superior performance, or it may use a different combination to provide more standard capabilities, but at a lower cost.

There is more to a computer (or a car) than just the buffers. But the use of buffers throughout computers (hard drives, CPUs, graphic cards, between sub-systems) are one of the reasons why computers got so cheap and so good so fast.

Will the cost and efficiency of electric cars improve as quickly as computers? Probably not. But we can expect that in the next 5 years… or less… electric cars will cost less to buy than Internal Combustion, and cost much less to operate. And superconductors will be a big part of the improvements we need to transition between gasoline to electric vehicles!

 

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