“Large format reduces all the ‘inactive’ materials, like packaging. So pack-level energy density will improve and cost will come down,” says Shirley Meng, a materials scientist who runs the Laboratory for Energy Storage & Conversion at the UC San Diego. It’s exactly the sort of beefy power supply that Tesla will need for its planned heavy-duty vehicles like the Cybertruck and its electric semi. But the real innovation in Tesla’s battery is what you can’t see.
In all EV batteries, a thin layer of copper foil serves as a current collector for the anode and a layer of aluminum foil for the cathode. A tab is joined to each of these current collectors and serves as the battery’s connection to the outside world. But these tabs hobble the performance of the cells and make them more difficult to produce. Manufacturers must use a specialized welding technique to connect them