Apr 29 2016

Some Battery Click-Bait

battery-24In an updated version of Dante’s Inferno there is one level of science hell that is specifically reserved for headline writers. In their hell there are endless signs pointing the way out of their torment, but all the signs are misleading or overhyped. They are therefore perpetually devastated by the difference between what they are promised and the reality.

Take the following headline (please): Researchers have accidentally made batteries that could last 400 times longer. They know the average person is going to read this and think they won’t have to recharge their cell phones but once per year (it’s recharge day, everybody). The headline is not technically wrong, it is just deliberately ambiguous in the use of the term “last.”

There are two ways in which batteries “last” – how long do they last on one charge, and how many charge-recharge cycles do they have. Guess which one we are talking about here.

The news item is also genuinely interesting, and would have grabbed my attention even without the click-bait headline. But first, a quick primer on batteries.

Interest in renewable and “green” energy is also driving interest in batteries. This is because many renewable energy sources, like wind and solar, are not on-demand. The wind blows when it blows, and the sun shines when it shines. If only there were a way to store that energy for use when it’s needed. This is where batteries come in.

As an aside, there are non-battery options for storing energy as well, like compressing air in large caverns, spinning up large flywheels, supercapacitors, or heating up rocks. But batteries are likely to play a key role even if some of these other options become viable. Batteries are also more portable that many of these other options, so your electric car is most likely going to require a battery.

Batteries are essentially a chemical way of storing energy. Electricity comes in converting one chemical to a higher energy chemical, and when it discharges the higher energy chemical converts back into the lower energy one. That is considered one charge-recharge cycle (which I will refer to as just “cycle”).

What makes battery technology so tricky is that, in order for the technology to be practical on a mass scale it has to simultaneously have a large number of desirable properties. These include: it has to charge and discharge rather quickly, it has to hold a sufficient amount of energy, it cannot be too heavy (if it’s meant to be mobile), it cannot be too big (it has a high energy density), it cannot depend upon rare, expensive, or (ideally) toxic components, it can be practically mass produced, it is stable (it doesn’t explode or catch fire easily), can operate efficiently in a practical range of temperatures, and it should have a large number of potential cycles without losing its capacity.

Any one of these properties has the potential to be a deal breaker. If the perfect battery requires a large amount of platinum then, while NASA may be happy, you will never see this for the average consumer. Other properties might limit their applications – for example, a heavy battery might work for home or utility energy storage, but not in a car.

Current lithium-ion battery technology is actually very good. Lithium is relatively cheap, the batteries have decent energy density, a large number of cycles, they can discharge fast enough to run a car and can recharge overnight, can be mass produced, and are relatively stable. They do have a small tendency to catch fire, and become less efficient in cold weather. Even with incremental advances and tweaks of this technology, we have a good and usable battery technology. Of course, we want more.

What is frustrating about reading many battery technology news items is that the headlines, and often the body of the article itself, focus on the one feature that was improved but ignore or downplay the negative features that render the advance essentially irrelevant (except maybe as a proof of concept).

With all this in mind let’s take a look at this latest battery advance.

First, the discovery was not all that accidental. PhD candidate Mya Le Thai was deliberately testing new battery technology, hoping to improve performance, and it did. She apparently did not predict exactly this advance, but so what.

What she did was use an electrolyte gel instead of battery fluid. She also coated the gold nanowires she was using in manganese oxide to make them less brittle. In previous experiments, the gold nanowires (thousands of times thinner than a human hair) were brittle and would not last.

When she started to cycle this setup she found that the nanowires could last for hundreds of thousands of cycles, compared to just a few thousand cycles for a typical battery. Even better, after so many cycles they only lost about 5% of their capacity, which is negligible.

A usable battery that can be cycled hundreds of thousands of times with minimal loss of capacity would be amazing. These batteries would essentially last the lifetime of the product they are in, or more. You could keep the battery from your previous laptop and use it in the next one (if they were compatible).

In electrical cars the cost of the battery is a huge component (could be $20,000), and if the battery loses charge after a few years that severely limits the lifespan of the car, or adds a huge upkeep expense. A battery that could last as long as the car would make them much more cost effective.

This would also be a huge benefit in that it would reduce the need to landfill or recycle dead batteries.

The article does mention (at the end) the two big caveats – the device they tested isn’t an actual battery. They were just testing the nanowires. It remains to be seen how they will function in a complete battery under real life conditions.

You probably also noticed that the nanowires are made of gold. Even though they may be small, mass producing anything made from gold is going to be expensive.

Still, this is potentially exciting. The idea of using a gel instead of a fluid may be key here, and may just apply to other batteries. The researchers are planning follow up experiments to see if this is so.

What is both exciting and frustrating is that news items like this one come out almost every week. This means there is a lot of exciting research being done in battery technology, but it also means that it is hard to know what the significance is of any of these apparent “breakthroughs.” Most are irrelevant and will not pan out because of one or more fatal flaws.

To some extent it’s probably best to ignore all the noise and click-bait headlines and just say, “Talk to me when you have a fully functioning and practical battery technology.”

Still, I can’t help reading these news items. The click-bait works – I have to know what the research actually showed. I’m always hoping it will be more than the usual proof of concept but we have no idea if it will really work.

Also, it seems to me that the real advances are incremental, slowly improving battery technology in the background without grabbing headlines. I guess it’s like wise investing vs winning the lottery. We all want to win the lottery, but reliable and cautious investing is probably a better idea.

Like this post? Share it!

12 responses so far