How exactly does an EV battery work?

The lithium-ion batteries found in smartphones power most electric vehicles. Lithium is highly reactive, and batteries made from it can hold high voltages and unique charges, creating an efficient and dense form of energy storage. These batteries are expected to continue to dominate EVs for future cost and performance improvements.

Currently, electric-car batteries typically weigh about 1,000 pounds, cost about $15,000 to manufacture, and have enough power to run a typical home for a few days. They should last 10 to 20 years as their charging capacity decreases over time.

Each battery consists of hundreds or even thousands of relatively soft lithium-ion electrochemical cells packed tightly, usually in the form of cylinders or pouches. Each cell includes a positive cathode (typically composed of metal oxides of nickel, manganese, and cobalt). negative, graphite-based anode; And in the middle is a liquid solution called electrolyte.

This is where the efficiency of lithium comes into play; The captured outer electron can easily be split off, leaving the lithium ion (the atom without the outer electron). The cell basically ping-pongs these ions and electrons back and forth.

During the charging cycle, an electric current introduced through an external source separates electrons from the lithium atoms in the cathode. Electrons flow around the external circuit to the anode – this is usually composed of graphite, a cheap, energy-dense and long-lasting material that stores energy – when ionized lithium atoms enter the anode through the electrolyte and are reunited with their electrons. During release cycles, the process is reversed. The lithium atoms in the anode are separated from their electrons again; ions pass through the electrolyte; And the electrons flow in the external circuit, which drives the motor.

The expansion of EVs has created a huge demand for the minerals needed to make batteries. The price of lithium carbonate, the compound from which lithium is extracted, remained relatively stable between 2010 and 2020 but increased tenfold between 2020 and 2022, prompting new investments around the world. More than a dozen battery plants and several mining projects are under construction in the US alone.

But the search for raw materials comes with many environmental, political and social costs.

Most of the cobalt in the common cathode comes from the Democratic Republic of Congo, which is notorious for child and forced labor. Much of America’s raw material supply is on tribal lands. Chile, a major producer of lithium, wants to wrest control of production from multinational companies. Meanwhile, mining companies and entrepreneurs have plans for ocean mining, which can damage fragile and poorly understood ecosystems (Chile is pushing for a ban on such ocean mining).

Battery developers are looking to reduce the use of rare metals and improve recycling. Startups and automakers race to design and build next-generation batteries that overcome material challenges and increase efficiency. New generation lithium-ion batteries have already eliminated the use of cobalt, for example. In addition, scientists have tried sodium-sulfur batteries, very cheap and abundant raw materials, and solid-state batteries, which – as the name suggests – replace the liquid electrolyte with solid compounds. They can offer a simpler, more stable, faster charging option.

Forecasts suggest that EVs will accelerate adoption and achieve price parity with cars based on internal combustion engines. And experts predict rapid expansion, consolidation and experimentation in battery manufacturing as countries and companies compete to compete among the sector’s more than a dozen players. The tiny journey of ions between the cathodes and anodes of battery cells could be one of the most important journeys of the next decade.