What's Inside a Battery Pack?
Explore the components, materials, and manufacturing costs of a lithium-ion battery energy storage system. From cathode chemistry to pack-level thermal management — every layer that determines $/kWh.
Click any component on the left to see its material composition, cost contribution, and engineering details.
Supply Chain: From Mine to Megapack
Lithium from brine (Chile, Argentina) or spodumene (Australia). Nickel/cobalt from laterite ores (Indonesia, DRC). Graphite from mines (China, Mozambique).
DRC produces 70% of world cobalt — a key reason LFP (cobalt-free) is gaining share
Precursor materials are mixed, calcined at 700-900°C, then milled to 5-15μm particles. LFP requires carbon coating for conductivity. NMC requires precise Ni:Mn:Co ratios.
Cathode production is the most energy-intensive step — 15 kWh per kg of CAM
Active material, binder, and conductive additive are mixed into slurry, coated onto metal foils (Al for cathode, Cu for anode), dried, and calendered to target porosity.
Electrode coating speed: 30-80 m/min. Faster = cheaper, but defects increase
Electrodes are stacked or wound with separator, inserted into cans, filled with electrolyte under vacuum, then sealed. Formation cycling (first charge) activates the SEI layer.
Formation takes 24-72 hours per batch — the biggest bottleneck in cell production
Cells are connected in series/parallel, BMS boards installed, thermal management plumbed, and everything housed in a fire-rated steel enclosure with HVAC and fire suppression.
A 5 MWh BESS container has 2,000+ cells, 100+ voltage sensors, and 50+ temperature probes
Lithium from brine (Chile, Argentina) or spodumene (Australia). Nickel/cobalt from laterite ores (Indonesia, DRC). Graphite from mines (China, Mozambique).
Precursor materials are mixed, calcined at 700-900°C, then milled to 5-15μm particles. LFP requires carbon coating for conductivity. NMC requires precise Ni:Mn:Co ratios.
Active material, binder, and conductive additive are mixed into slurry, coated onto metal foils (Al for cathode, Cu for anode), dried, and calendered to target porosity.
Electrodes are stacked or wound with separator, inserted into cans, filled with electrolyte under vacuum, then sealed. Formation cycling (first charge) activates the SEI layer.
Cells are connected in series/parallel, BMS boards installed, thermal management plumbed, and everything housed in a fire-rated steel enclosure with HVAC and fire suppression.
LFP vs NMC811: Which Chemistry?
LFP (Lithium Iron Phosphate)
Dominant for utility-scale BESS. Lower cost, longer life, safer. Preferred by Tesla Megapack, BYD, CATL.
NMC811 (Nickel Manganese Cobalt)
Used where space/weight matters (EVs, behind-the-meter). Higher energy density but shorter life and supply chain risk.