Last week I happened to catch an intriguing documentary on NOVA called Search for the Super Battery.
The topic is of intense interest to me, as the development of better, cheaper batteries is critical for both the future of electric vehicles (EVs) and for the future electrical grid. Battery improvements are needed to increase the range of EVs, and cheaper batteries can help drive down the costs of EVs so more consumers can afford them.
For the electrical grid, increased penetration of renewables poses some challenges because of their intermittent nature. Since the wind could stop blowing at any time, and the sun’s radiation can only be captured during the day, these sources of power need to be backed up. Cost-effective storage of power could enable essentially unlimited penetration of renewables into the grid.
Thus, tremendous effort has gone into battery development in recent years. The effort is paying off, with prices for battery cells falling by 70 percent between 2012 and 2017, according to PV Magazine. But costs need to continue to decline to make widespread use of utility-scale battery storage a reality.
Lithium-ion batteries have become the battery of choice in many consumer electronics such as laptops, and in electric vehicles such as those produced by Tesla. But there are a couple of problems with these types of batteries that need to be resolved.
For reasons that are explained in the documentary, the use of lithium-metal electrodes enables a greater energy density than conventional lithium-ion batteries. But lithium-metal electrodes can develop finger-like structures called dendrites that will eventually short-circuit the battery.
The solution to this problem was to replace the lithium-metal electrode with a carbon electrode with a lattice structure that houses lithium ions. Thus, the lithium-ion battery was born, albeit with a lower energy storage capacity than a battery utilizing a solid lithium-metal electrode.
Lithium-ion batteries also suffer from one other shortcoming that has been the subject of numerous news articles. If these batteries are damaged, they can explode or catch fire. This has happened in laptops, cell phones, and EVs. If damaged, all of the energy stored inside the battery can release over a short period of time, and the result can be a hot, intense fire.