How an EV Battery Is Made: From Minerals to a Finished Pack

1. The raw materials

A lithium-ion cell has four main parts: a cathode (positive electrode), an anode (negative electrode), a separator between them and a liquid electrolyte. The cathode is where most of the critical minerals live. Common chemistries are NMC (nickel-manganese-cobalt), NCA (nickel-cobalt-aluminium) and LFP (lithium iron phosphate). The anode is usually graphite, sometimes with a little silicon. Lithium is present in both the cathode and the electrolyte.

• Lithium — from salt-flat brines (South America) or hard-rock spodumene (Australia, Africa).
• Nickel and cobalt — used in NMC/NCA cathodes for high energy density; cobalt sourcing is the most scrutinised.
• Iron and phosphate — used in LFP cells, which are cheaper, longer-lasting and avoid nickel and cobalt.
• Graphite — natural or synthetic, for the anode.
• Copper and aluminium — the thin foils that carry current from each electrode.

2. Making the electrodes

The active cathode and anode materials are mixed into a slurry with binders and conductive carbon, then coated onto long rolls of aluminium (cathode) or copper (anode) foil. The coated foil is dried, pressed to a precise thickness and slit into strips. The quality of this coating is one of the biggest factors in how long the cell lasts.

3. Building the cells

Electrode strips and the separator are stacked or wound into one of three formats: cylindrical (like a large AA cell), prismatic (a flat rectangular can) or pouch (a soft, flat envelope). The assembly is placed in its casing, filled with electrolyte in a moisture-free room, sealed, and then 'formed' — charged and discharged slowly for the first time to create a stable protective layer on the anode. Cells are then aged and tested; any that drift are rejected.

4. Modules, pack and the brain

Cells are grouped into modules, and modules into the pack, wired in series and parallel to reach the car's voltage (usually 400 V or 800 V) and capacity. A battery management system (BMS) monitors every cell group's voltage and temperature, balances them, and controls charging and discharging to keep the pack safe. Cooling plates or channels run through the pack because temperature control is what keeps lithium cells healthy. The pack is sealed in a strong, waterproof case and bolted into the car's floor, where it also stiffens the chassis.

5. Testing

Finished packs are tested for capacity, insulation, leaks and crash safety before they ship. Regulators require packs to survive crushing, penetration, overcharge, short-circuit, vibration, water immersion and fire exposure without a dangerous failure.

Newer approaches such as cell-to-pack designs (skipping modules) and sodium-ion or solid-state chemistries are aimed at cutting cost, weight and the amount of critical minerals per kWh.