Build better batteries

Truth be told, the average gadget enthusiast is unaware of three important points regarding batteries. (In February 2017, PBS aired a special episode of the NOVA program titled "The Search for the Super Battery," hosted by me. After a year of visiting labs and interviewing scientists, I admit that batteries preoccupy me these days.)

First point: the batteries you probably deal with often are the ones in your cell phone or laptop. But it can be said, and many scientists say so, that batteries are the secret to dealing with infinitely larger problems, such as energy, transportation and climate change.

For example, today only about one percent of the new cars sold in the US are electric cars. One reason for this is that they are more expensive than gasoline powered cars. Another reason is the concern regarding the driving range: consumers fear that they will be stuck with empty batteries in a place far from their home. The cheaper, higher capacity batteries being developed today are designed to address both of these problems.

And in addition to this there is also the matter of the electricity network. Electricity is not like water, which stands and waits in a pipe until you turn on the tap. When you light a lamp, the energy it needs must be produced at that moment, in real time. Therefore, the electricity companies set aside a lot of time to deal with very sharp fluctuations in the demand for electricity. At night, when everyone is asleep, there is almost no demand, then at 5 in the afternoon, when people come home from work, there is a huge peak in demand. The power companies actually maintain expensive, inefficient backup stations that are only activated occasionally to handle peak demand, such as those caused by heat waves.

Grid-connected batteries will be able to moderate these impossible fluctuations. And perhaps more importantly, grid batteries will be able to store solar energy when the sun is shining, and wind energy when the wind is blowing, for use when really needed. So far we have not been able to subordinate the sun and the wind to the schedules of our daily life.

The second point that people are not aware of: our complaints are usually about the battery capacity: how long the devices can operate between charges. But the truth is that high capacity (or energy density) is only one item on the industry's wish list. We also want the batteries to be cheap, harmless to the environment when they are out of use, long-lasting (that is, they can be charged thousands of times), compact, light (especially for electric cars) and safe to use. It's really unpleasant when the phone explodes, Samsung people will testify.

In general, you can't have everything in one battery. But on the other hand, you don't always need everything. The mains batteries, for example, should not be portable or compact. And so the possibility of usingflow batteries, for example, based on chemicals stored in huge tanks and flowing past each other in reaction cells, or inFlywheel batteries, based on a metal disc, such as steel for example, weighing tens of kilograms, rotating at a speed of thousands of revolutions per minute in a frictionless chamber (it floats in a vacuum due to the force of a magnet). Its rotation is done at night, so the energy needed for this is cheaper, and the kinetic energy of the rotation is used during the day to generate electricity.

The third important point: the batteries did improve over the years. We don't feel it because at the same time our devices have become faster, more powerful and more energy hungry. In fact, if you plugged a cell phone from 1995 into a current iPhone battery it would probably last a full year on a single charge.

More great innovations are expected. For example, the materials scientist Mike Zimmerman managed to replace the highly flammable liquid, in which the ions move when charging or discharging a battery (the electrolyte), with one piece of a special plastic sheet. And here it is: a battery that cannot catch fire and not explode. And because it doesn't explode, Zimmerman can take advantage of the chemistry of lithium metal itself instead of the chemistry of lithium ions. The metal has a much higher energy density, but it is considered too dangerous to use in today's batteries, which are based on a liquid electrolyte. This way you can extend the duration of the operation.

So those who want to complain about batteries, do it now. Soon their reputation will increase considerably.