EV batteries are made through a multi-stage process that starts with mining raw minerals, transforms them into precisely coated electrode sheets, assembles those sheets into sealed cells, and finally integrates hundreds or thousands of cells into a temperature-controlled pack. The entire journey from raw ore to finished battery pack involves some of the most tightly controlled manufacturing environments in any industry, with humidity levels so low that a single breath of moist air could ruin a batch of cells.
Raw Materials That Go Into the Cells
The two most common cathode chemistries in today’s EVs are NMC (nickel-manganese-cobalt) and LFP (lithium-iron-phosphate). In an NMC 811 cathode, the metal content breaks down to 80% nickel, 10% manganese, and 10% cobalt by proportion. Regardless of the specific chemistry, lithium makes up roughly 72 grams per kilogram of cell weight, a ratio that hasn’t changed much even as manufacturers shift to newer formulations.
On the anode side, graphite remains the dominant material. Most EV anodes use either natural graphite mined primarily in China and Mozambique or synthetic graphite produced from petroleum coke. These raw materials are refined, purified, and processed into fine powders before they ever reach a battery factory.
Making the Electrodes
Electrode manufacturing is where chemistry meets precision engineering. Both the cathode and anode go through a nearly identical process: mixing a slurry, coating it onto metal foil, drying it, and pressing it to exact thickness.
For the cathode, the active material powder (the nickel-manganese-cobalt mix, for example) is blended with carbon black as a conductive additive and a polymer binder, all dissolved in a chemical solvent. This creates a thick, ink-like slurry that needs to be perfectly uniform. Any clumps or inconsistencies will create weak spots in the finished battery. The slurry is then fed through a slot-die coater, a machine that spreads an ultra-thin, even layer onto aluminum foil moving at high speed. The coated foil passes through a long drying oven to evaporate the solvent, leaving behind a dry electrode film bonded to the foil.
The anode follows the same basic steps but uses graphite as the active material and copper foil as the base. The graphite slurry is spread onto the copper, then vacuum-dried at around 80°C for several hours. After drying, both electrodes are run through heavy rollers that compress them to a precise, consistent thickness. This compression step, called calendering, directly affects how much energy the finished cell can store.
The Ultra-Dry Assembly Environment
Once the electrodes are cut to size, assembly happens inside dry rooms with humidity levels below 2% relative humidity. The dew point in these rooms typically falls between -35°C and -45°C, meaning there’s less than 0.3 grams of water per kilogram of air. For the most sensitive steps, like filling cells with electrolyte, some factories push dew points below -60°C or even -80°C. Lithium and the liquid electrolyte are extremely reactive to moisture, so even trace amounts of water vapor can trigger chemical reactions that degrade the cell before it’s ever used.
Assembling Individual Cells
Inside the dry room, the cathode sheet, anode sheet, and a thin plastic separator are layered together. The separator keeps the two electrodes from touching (which would cause a short circuit) while allowing lithium ions to pass through during charging and discharging.
How these layers come together depends on the cell format. For cylindrical cells, the kind Tesla popularized, the electrode sheets and separator are wound into a tight spiral around a central core, like rolling up a sleeping bag. The coil is then inserted into a metal canister. Pouch cells use a similar winding approach or a stacking method, where individual electrode sheets are layered on top of each other like pages in a book. Prismatic cells, the rectangular format common in many European and Asian EVs, can use either technique depending on the manufacturer.
After the electrodes are in place, liquid electrolyte is injected into the cell. This is the step that demands the lowest humidity. The electrolyte is a lithium salt dissolved in an organic solvent, and it serves as the medium through which lithium ions travel between the cathode and anode. Once filled, the cell is sealed. For pouch cells, sealing happens under vacuum: the chamber is flushed with nitrogen gas to remove any remaining room air before the final seal is pressed.
Formation: The First Charge
A freshly assembled cell isn’t ready to use. It first goes through “formation,” a carefully controlled initial charging process that activates the cell’s chemistry and creates a protective layer on the anode surface. This layer, called the solid electrolyte interphase, is critical to the battery’s long-term health and lifespan.
Formation typically involves three very slow charge-and-discharge cycles at low current rates. For large pouch cells, the cells are wetted for about two hours before the first charge begins, and each cycle charges to 4.2 volts and discharges down to 2.9 volts. Smaller cells may be wetted for up to 10 hours and charged at slightly higher rates. The entire formation process, including rest periods and quality checks, can take days per cell. This is one of the biggest bottlenecks in battery manufacturing because every cell in a factory needs individual time on a charging rack.
After formation, cells go through an aging period where they sit at controlled temperatures while factory systems monitor for voltage drops. Any cell that loses voltage faster than expected has a defect and gets pulled from the line.
Building the Battery Pack
Individual cells are grouped into modules, and modules are combined into the final battery pack that sits beneath the floor of an EV. This pack-level assembly is as much structural engineering as it is electrical work.
Each cell is connected to its neighbors through busbars (metal connectors that carry current between cells) and wired into a battery management system. The management system monitors every cell’s voltage, temperature, and state of charge in real time, balancing the load so no single cell gets overworked. It also controls charging speed and triggers safety shutoffs if something goes wrong.
Thermal management is one of the most engineered aspects of the pack. There are four main approaches: air cooling, liquid cooling, phase-change materials, and thermoelectric systems. Most long-range EVs use liquid cooling, where a network of channels or cold plates circulates coolant around the cells to pull heat away during fast charging or hard driving. Air-cooled systems are simpler and lighter but limited to shorter-range vehicles with smaller packs. Some manufacturers combine approaches, using a phase-change material for passive heat absorption alongside an active liquid system for peak loads.
The pack housing itself is typically a sealed aluminum or steel enclosure that doubles as a structural component of the vehicle’s chassis. It’s designed to protect cells from road debris, water intrusion, and crash impacts. Seals, vents, and pressure relief valves ensure that if a cell does fail, gases can escape in a controlled direction rather than causing a catastrophic rupture.
What This Costs Today
The average lithium-ion battery pack price dropped to $108 per kilowatt-hour in 2025, an 8% decline from the previous year. Battery-electric vehicle packs specifically came in even lower at $99 per kilowatt-hour, marking the second consecutive year below the symbolic $100 threshold that the industry long viewed as the tipping point for cost parity with gasoline cars.
Chemistry matters for price. LFP packs, which skip cobalt and nickel entirely, averaged $81 per kilowatt-hour. NMC packs, with their higher energy density but more expensive metals, averaged $128 per kilowatt-hour. The growing adoption of LFP in vehicles from Tesla, Ford, and Chinese manufacturers is a major driver of the overall price decline, and analysts expect pack prices to continue falling into 2026.
Recycling at End of Life
When an EV battery reaches the end of its useful vehicle life, typically after 8 to 15 years, the materials inside can be recovered and fed back into new battery production. The most promising approach is hydrometallurgical recycling, which uses chemical solutions to dissolve and separate the metals from spent cells. Recovery rates are high: over 95% for cobalt and nickel, over 90% for lithium, with one recent process achieving 97.2% purity for recovered lithium carbonate and an overall lithium recovery efficiency of about 80%.
These recovered materials are pure enough to go directly back into new cathode production, creating a partial closed loop that reduces dependence on mining. As millions of first-generation EV batteries begin reaching retirement age over the next decade, recycling capacity is scaling rapidly to match.