Lead-acid batteries
A standard car battery is roughly 60% lead, 25% sulphuric acid electrolyte and 10% polypropylene, with the balance in separators and connectors. At a permitted recycling plant the process runs like this:
- Breaking. Batteries are fed into a hammer mill and crushed. The fragments go into a separation tank.
- Separation. Heavy lead and lead paste sink; polypropylene floats and is skimmed off for washing and re-pelletising into new battery cases.
- Acid treatment. The electrolyte is drained and either neutralised to water, or processed into sodium sulphate for use in detergents and glass.
- Smelting. Lead grids and paste are smelted in a furnace, refined to remove impurities and cast into ingots.
- New batteries. Around 80% of the lead in a new car battery sold in the UK is recycled lead. The loop is almost completely closed.
Lithium-ion EV batteries
EV packs are newer and the recycling industry is still scaling up, but the route is established. Packs are discharged to a safe state, dismantled to module level and either shredded under inert atmosphere to produce “black mass” (a concentrate of cobalt, nickel, lithium, manganese and graphite) or fed to a pyrometallurgical furnace. The black mass is then refined by hydrometallurgy to recover battery-grade metals. Copper, aluminium and steel from the casing and busbars are recovered conventionally.
Packs with plenty of life left may instead be repurposed for stationary storage. Where that’s possible we’ll tell you, because it affects the price.
Why it matters
Lead is toxic. Sulphuric acid is corrosive. Lithium cells can start fires that are very hard to put out. Recycling through the proper channels keeps all of that out of soil, water and landfill, and dramatically reduces the energy and mining needed to make new batteries. That’s the “protect” in recycle, reuse, protect.