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EV battery life doubled overnight?

Right now, lithium ion batteries are king.

Whether it's your smartphone, your car, your ebike or the cordless vacuum cleaner that keeps your carpet looking as good as new, chances are that the batteries inside are some form of lithium-ion technology.

However, there is a problem with such batteries: they don't last forever.

In fact, sometimes they don't even last very long at all.

A few hundred charge cycles is probably the best you can expect if you are constantly charging to 100 percent capacity and then discharging almost totally on a regular basis.

There are big hopes that "better" battery tech will overcome the relatively limited lifespan of today's batteries but more immediate help may already be available.

A study conducted by researchers in Europe has discovered that the conventional methods used to charge these batteries is part of the problem in their limited longevity.

As this piece on Science Daily describes, the new charging protocol can produce a marked increase in the service life of regular lithium ion batteries.

For those who don't know, lithium batteries are usually charged using a system known as CC/CV, where a constant current is used up to the point where the "terminal voltage" across a cell (typically 4.2V) is reached. At that point, the voltage is held constant and the current slowly decreases until it becomes effectively zero. At that stage, the battery is fully charged.

All of this is done with regular DC current. Smooth and uninterupted.

It's done this way because it's easier and thus keeps charging designs relatively simple and cheap to manufacture.

The proposed new system relies on pulses of higher current rather than a continuous stream of electricity.

This is not a new idea or technology. Indeed, pulsed chargers have been around for a long time and have helped in older battery technologies such as nickel-cadmium. With those older chemistries, pulsed charging helped reduce the formation of dendrites (sharp crystals that, over time would grow and create a short-circuit between the plates of the cell).

According to the tests performed by the researchers in Europe, applying this pulsed charging technique to lithium batteries is able to extend their useful cycle life by around 100 percent. This means that existing cells could be able to last twice as long as they do under more traditional charging regimes.

Given that the batteries are the single most expensive element of a modern EV, the potential to double the useful life of those batteries is quite a significant breakthrough -- even moreso when it only requires a new charger and not different chemistry to achieve.

Given that this is pretty simple stuff these days, thanks to the ready availability of high-current FET devices and microcontrollers, I may just do some experiments of my own and see whether I can get any significant increase in the life of the lithium battery packs I use in my drones and RC model aircraft. Ah.. time to order some more Raspberry Pi Nanos I guess.

In the meantime, if this all pans out, you can probably expect to see some pretty rapid update by EV manufacturers and charging network providers -- although it would mean writing off a fairly sizeable chunk of change through the retirement of existing chargers.

The problem with a market that is as technology-based as EVs is that there are always going to be points where old tech is cast aside in favour of new tech. That will hurt but, when the gains are significant (as in this case), it's a pain that will just have to be endured by those who've already invested heavily in what is about to be come "yesterday's technology".

Carpe Diem folks!

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