CT scans of BYD car parts

The cell that made BYD famous is the Blade: a long, thin Lithium Iron Phosphate (LFP) prismatic designed to lay flat across a vehicle floor, with the cells themselves forming part of the car's structure rather than sitting inside a separate enclosure. This prismatic cell is NOT a Blade, but it does share the same chemistry. LFP trades some energy density against the lithium-ion chemistries that dominate Western EV packs, but it runs cooler, tolerates more charge cycles, and replaces the nickel, manganese, and cobalt used in other chemistries with iron. That substitution is what gives LFP its stability, as well as cost and supply chain advantages. While Tesla sources cells from Panasonic and LG and most Western automakers buy from dedicated battery suppliers, BYD designs and manufactures its own, from chemistry to finished pack.

The two threaded terminals are the densest structures in the cell (negative on the left, positive on the right). Between them sits the explosion-proof valve: a pressure relief feature that vents the cell if internal gas pressure exceeds safe limits. It’s a last-resort safety mechanism. The LFP chemistry in this cell is stable enough that the valve rarely needs to function, which is precisely why BYD uses it.

Lowering the opacity of the aluminum housing, the cell resolves into two distinct electrode stacks. Each stack connects to the terminals above. Splitting the cell's capacity across two parallel jellyrolls rather than one improves current distribution and makes better use of the prismatic casing geometry. The Blade cell takes a different approach: its extreme length and thinness suits flat-stacked electrodes, sheets of anode, separator, and cathode layered directly rather than wound.