How do you make a lithium-ion battery and what the heck is a “gigafactory”?
These questions have been buzzing around the circles of local Nevada policymakers after a recent blog by Elon Musk, CEO of Tesla Motors: www.teslamotors.com/blog/gigafactory
Musk’s company is considering building a large-scale manufacturing facility in Nevada that will exceed the combined production of all existing lithium-ion battery factories worldwide.
Doubling manufacturing capacity of lithium-ion secondary cells will be driven by Tesla Motors, if the company ramps up production of its third-generation electric car to 500,000 units per year by 2020.
The energy storage density in secondary lithium-ion battery cells can be four times greater than conventional lead-acid battery technologies used in the automotive industry today. Lithium-ion battery cells also have a charge/discharge cycle life exceeding eight years or 100,000 miles of vehicle travel.
The challenge to Tesla Motors and other electric car manufacturers will be to drive down production costs of both the battery cells and integrated battery packs. Tesla plans to achieve cost savings by combining and automating all phases of production under one gigafactory, that can leverage economies of scale.
Arizona, New Mexico and Texas are also being considered as possible locations. However, even if another state is selected, Nevada can still benefit from a two-fold increase in lithium productivity. The Silver State is the largest producer of lithium products in North America.
A next-generation Tesla Motors electric car like the Model S will require a battery pack with 85 kilowatt-hours of energy storage capacity, to travel 300 miles before needing to be recharged.
The Model S battery pack is composed of more than 8,500 cylindrical lithium-ion battery cells mounted in the floorboard of the vehicle.
To manufacture all those cells requires about 90 pounds of raw lithium mineral. If Tesla Motors can produce half a million battery packs by 2020, its gigafactory would require at least 22,500 tons of high-quality lithium each year.
Located in the Clayton Valley in Esmeralda County, about 220 miles northwest of Las Vegas, the Rockwood Lithium mine has been a rich source of lithium for 50 years.
Ancient volcanic activity in the region uplifted liquid brines into underground aquifers near the earth’s surface that contain lithium mineral concentrations averaging 200 parts per million.
The brines are easier and cheaper to extract from the ground than hard rock mining techniques used by other lithium mines in the U.S.
Just drill and pump the muddy brine into a surface holding pond. Then bake it under the dry Nevada sun to evaporate the liquid.
Mix in soda ash to separate the raw minerals into lithium carbonate and sodium chloride, or add limestone to make lithium hydroxide. Both chemical compounds are used to manufacture the cathode component of a lithium-ion battery cell.
Lithium ions are atoms that are either missing an electron or have one extra electron. Lithium atoms normally have only one electron in their outermost valence shell, so they can be easily “ionized” to shed or acquire electrons. Lithium ions that are missing an electron tend to migrate to the cathode of a battery cell while lithium ions with excess electrons tend to migrate to the anode of the cell.
The exploration of Nevada lands for lithium resources began during the atomic age, when isotopes of lithium were used to create atomic reactions that triggered nuclear explosions.
During the following decades, large deposits of lithium were discovered, embedded in hectorite clay within Northern Nevada’s Humboldt County. A potential yield of 11 million tons of lithium carbonate may someday be recoverable from this region.
Western Lithium has staked claims to sites in the Kings Valley at a location not far from Interstate 80 and the railroad.
Although the extraction of lithium carbonate from clay is more expensive than brine-based resources, the company is hoping to monetize the clay itself as a drilling additive that can be sold to oil and natural gas producers for fracking applications. Potassium sulfate is also a byproduct from this mining project that can be sold to the fertilizer industry.
At full production, the Western Lithium mine could produce more than 30,000 tons of lithium carbonate equivalent per year, more than enough to meet the needs of a lithium-ion battery gigafactory.
Stan Hanel has worked in the electronics industry for more than 30 years and is a longtime member of the Electric Auto Association and the Las Vegas Electric Vehicle Association. Hanel writes and edits for EAA’s “Current Events” and LVEVA’s “Watts Happening” newsletters. Contact him at firstname.lastname@example.org.