From rock to cell

Extraction, trucks, crushing, refining, manufacturing and transport of a battery.

From deposit to a clean cell

1. Extract

Lithium can come from brines pumped and concentrated through solar evaporation over months in enormous ponds — the dominant method at salt flats like Atacama, in Chile —, or from hard rock that is drilled, blasted, loaded and crushed, as at Australia's spodumene deposits. Nickel and cobalt come from ores with different mining and smelting processes; graphite can be mined naturally or synthesized at high temperature from petroleum derivatives. Copper and aluminum, present in almost every electrical component of the cell and the vehicle, connect and give structure to the whole assembly.

In an open-pit mine, drills, shovels, excavators and enormous haul trucks capable of carrying hundreds of tonnes per trip do the work. Some shovels are electric; many haul trucks still burn diesel, and a single truck of this kind can consume several hundred liters of fuel per hour of continuous operation. Its hourly consumption, however, does not answer the decisive environmental question: it depends on the load carried, the road gradient, the distance traveled, idle time and vehicle size. The genuinely comparable figure is energy and emissions per tonne of refined material, which also systematically worsens as ore grade falls and far more tonnes of waste rock have to be moved to obtain the same amount of usable lithium.

2. Concentrate and refine

The rock is crushed and ground into fine powder; then come stages of physical separation, heat, pressure and a combination of chemical reagents specific to each mineral. The final product must reach extraordinary purity — on the order of 99.5% or higher for battery use, well above what any other industrial use of lithium requires. This phase consumes large amounts of electricity, fuel and water, and generates tailings, residual brines or sludge that require long-term management and containment, exactly as in any other metal mining and refining activity.

3. Manufacture

The active cathode and anode powders are mixed with binders and solvents into a homogeneous paste, which is coated onto copper or aluminum sheets with a thickness controlled to micrometer precision. Electrode and separator are stacked or rolled in extremely dry rooms — even minimal ambient humidity can ruin an entire batch of cells —, the liquid electrolyte is added, and each cell then goes through initial formation cycles and quality control before being deemed fit for use. Maintaining near-zero humidity and strictly controlled temperature throughout the manufacturing room consumes a significant amount of energy: the specific electricity powering that factory — clean or coal-based — can radically change the cell's final carbon footprint, even if the design and chemistry are exactly the same.

4. Integrate and transport

Individual cells, control electronics, protective casing, cooling system and structural crash protection are assembled into the final battery pack. Materials can cross continents several times along this chain, because extraction, refining, cathode manufacturing, cell assembly and final vehicle or equipment assembly are, in current practice, geographically concentrated in different regions of the world — each ocean crossing adds its own transport, time and emissions before the battery reaches its final destination.

What actually reduces material cost

  • Choosing a battery sized to the service and avoiding range that is rarely used.
  • Manufacturing with low-emission electricity and improving plant yield to reduce defective scrap.
  • Requiring traceability of mine and refinery, water use, tailings and labor conditions.
  • Designing modules that are repairable, accessible and easy to disassemble.
  • Keeping the vehicle or equipment long enough to spread its manufacturing footprint over many years of service.
  • Recovering factory scrap today and used batteries once they arrive at volume.

There is no identical "backpack" for every battery. Chemistry, size, supplier, industrial electricity mix and lifespan can all change the result. That is why a serious comparison states those assumptions explicitly.

The numbers, with their source

A whole salt flat for one tonne of lithium

At the Salar de Atacama (Chile), producing one tonne of lithium carbonate requires, on average, evaporating approximately half a million liters of brine (about 500 m³) in enormous solar ponds over months. A detailed study of this specific operation calculates a potential water-equivalent impact of 442 m³ per tonne of lithium product. The concentrated brine is then trucked about 232 km to the refining plant in Antofagasta, and emissions from this first stage of the chain are estimated at around 4,022 kg of CO₂ equivalent per tonne of lithium carbonate. Some estimates suggest mining in this area can consume up to 65% of the region's available water — a figure that, even accounting for variation between studies, points to real water stress on an already fragile desert ecosystem.

Sources: ScienceDirect — Water footprint of battery-grade lithium production in the Salar de Atacama; ScienceDirect — Carbon footprint and water inventory of lithium production at the Atacama Salt Flat.

Not every salt flat consumes the same water

The extraction method itself changes the result a great deal: at the Hombre Muerto salt flat (Argentina), a hybrid evaporation and direct lithium extraction (DLE, a newer technology) scheme reports a total water use of 71 m³ per tonne of Li₂CO₃ — a notably different figure, higher by some comparisons and lower by others, than Atacama's or that of the nearby Olaroz salt flat. This shows that "salar lithium" is not a single category: the specific extraction technology used at each deposit matters as much as the deposit itself.

Source: ScienceDirect — Life cycle assessment and water use impacts of lithium production from salar deposits.

How much CO₂ it costs to manufacture each kilowatt-hour of battery

Manufacturing a typical electric-vehicle battery pack emits, according to different estimates, between 40 and 200 kg of CO₂ equivalent per kilowatt-hour of capacity, with an average cited around 100 kg CO₂/kWh for current global production. Of that total, roughly 40% comes from raw-material extraction (lithium, nickel, cobalt, graphite, copper), while the remaining 60% corresponds to cell production and assembly, a phase that consumes a lot of electricity and whose footprint depends, again, on which electricity mix powers that specific factory. The most advanced manufacturers in decarbonizing their chain are already targeting below 20 kg CO₂/kWh, a reduction of up to tenfold compared with today's most carbon-intensive plants.

Sources: ICCT — Effects of battery manufacturing on electric vehicle life-cycle GHG; McKinsey — The race to decarbonize electric-vehicle batteries.

What this table is missing

These figures describe manufacturing; they do not include the energy cost of international transport of materials between continents — mining, cathode refining and final assembly usually happen in different countries — nor the impact of the use and recycling phases, developed in this section's other leaves.

Sources

On mining machinery

Avoid converting an engine's maximum power or a tank's volume into real consumption. To audit an operation, ask for annual fuel and electricity use, tonnes moved, mineral produced, ore grade, and refining emissions. That allows comparing mines and spotting when a spectacular figure lacks a denominator.