Building a Better Lithium Battery
Last year I wrote about A Battery That Could Change The World, which addressed the development of a solid-state lithium battery that won’t catch fire if damaged. More recently, I wrote about a different approach to the problem of fires in lithium-ion batteries, which quickly dissipates the heat released from a fire in a cell before it can spread.
Development of better batteries is critical as more electric vehicles hit the roads, and as electric utilities seek better options for storing power from intermittent renewables. In addition, lithium-ion batteries have become ubiquitous in our lives through any number of consumer electronics.
Three key issues that companies are working to address are safety, energy density, and cost. Safety mainly concerns the possibility that lithium-ion batteries can catch fire if damaged. The two aforementioned stories are mostly focused on that aspect of the problem.
The problem of energy density concerns the ability to store energy in a specific volume (or weight). Batteries have low energy density compared to liquid fuels. Gasoline, for example, has about 100 times the volumetric energy density of a Li-ion battery pack. However, the greater efficiency of an electric motor versus a combustion engine substantially narrows the gap for usable energy.
Finally, batteries have historically been an expensive way to store energy. According to the Energy Information Administration, in recent years the cost to install large-scale battery storage systems was typically thousands of dollars per kilowatt (kW). In comparison, the capital costs of producing electricity by power plants can be under $1,000/kW. Importantly, lower battery storage costs would be a critical enabler for utilities seeking to incorporate higher levels of intermittent renewables into the power mix.
It isn’t surprising that companies are working to solve each of these battery challenges. But the solution to one problem can create another.
Consider energy density. Lithium-metal batteries allow for much higher energy density than lithium-ion batteries by using lithium-metal electrode instead of graphite electrode. But lithium deposits called dendrites can spontaneously grow from the lithium metal electrodes whenever the battery is being charged. If these dendrites bridge the gap between the anode and cathode (the two opposite electrodes in a battery), a short circuit results. This can cause the battery to fail, which may result in a fire or explosion.