Elon Musk announced a new battery type that Tesla will be producing for its cars. Dubbed the 4680, it is 80mm tall and 46mm wide. This battery eliminates the use of cobalt, one of the most expensive materials in the battery, one that is also dangerous to mine, and most of that comes from the Democratic Republic of Congo in Africa. Eliminating cobalt from a lithium-ion battery is something that battery scientists have been trying to do for years.
Their plan is to halve the cost of lithium-ion batteries within a few years. This new battery is part of the plan. The implications are not only for more affordable cars, but all vehicles, which will positively affect prices on e-bikes and electric motorcycles, scooters, and all of electric mobility.
Tesla started nearly from scratch with this battery design. It’s not just a bigger battery. There’s some silicon in today’s battery cells, but not as much as this new battery will have. Silicon expands to 4 times its size when charged with lithium, posing a potential problem. It does, however, store 9 times more lithium than graphite. Silicon is the second most abundant element in the earth’s crust after oxygen, which means that it can be cheap to obtain. Tesla uses raw silicon as part of a new chemistry for this cell.
“Stabilize the surface with an elastic ion-conducting polymer coating that’s applied through a very scalable approach,” Drew Baglino (SVP, Powertrain and Energy Engineering at Tesla) said. This elastic polymer allows for expansion of the silicon and offers longer cell life and 20% more range.
They’ve replaced the cobalt cathode with nickel, which offers the same energy density, but with a 15% reduction in cost ($/KWh) as well as being far more environmentally and ethically friendly.
Tesla doesn’t want to be constrained by the availability of nickel, however, so they’re also formulating some cells with iron as a cathode for long cycle life, including Powerwalls, a mixture of nickel and manganese for long range (cars and crossovers, e.g. the Model X and Model 3), as well as high nickel for higher mass vehicles like the Cybertruck and Tesla Semi.
Lithium is abundant enough, in fact, there’s enough lithium in Nevada to electrify all the gasoline-powered cars in the U.S. Tesla has discovered a safe, environmentally-friendly way to pull lithium out using sodium chloride. Tesla is building factories to produce all the materials for the cells in the U.S. By producing it within the U.S., the high transportation costs of importing the materials from around the world is cut dramatically, as is the carbon footprint of all that transportation.
The new cells are designed without tabs, and have shorter pathways for the electrons to travel. They’re also simpler to build, with fewer parts. What all this means in English, is that it offers 5 times the energy, 6 times the power, and a 16% increase in range with just this form factor change alone. Oh, and they will be 14% less expensive overall and able to charge faster.
Tradition lithium-ion batteries use a wet process to make the electrodes that includes mixing the powdered element with water or a solvent, then they apply it as a coat and have to run it through a large oven to dry it. They’ve changed this process to just pressing the dry materials into a film, eliminating the need for solvents and solvent recovery and the drying ovens. This translates to a ten-fold reduction in manufacturing footprint, and also a ten-fold reduction in energy expenditure to produce the materials.
Tesla will start right away with production on these cells at their 10 Gigawatt production facility in California, but won’t be at full, scaled up capacity until almost 2022. By 2030 they plan to be measuring battery manufacturing output by Terawatts. To give an example of how much energy that is, worldwide use of electricity is 15 Terawatts per year.