Today’s electric vehicles (EVs) mainly use batteries with cathodes made of lithium nickel manganese cobalt oxide (NMC) or lithium iron phosphate (LFP). Tesla and BYD, the world’s largest EV companies, have each adopted one of these chemistries. Chinese carmaker BYD uses LFP batteries, and Tesla chose NMC.

To determine how the two rivals’ batteries stack up against each other, a team of engineers and materials scientists in Germany took apart one cell from each company’s battery pack, which contain dozens of cells (Cell Rep. Phys. Sci. 2025, DOI: 10.1016/j.xcrp.2025.102453). The cells’ materials and designs held some surprises.

EV makers guard battery technology tightly. But engineering firms regularly disassemble batteries to peek at their innards. Battery engineers Jonas Gorsch and Moritz Frieges of RWTH Aachen University and their colleagues took a scientific sledgehammer to Tesla and BYD battery cells and did a detailed side-by-side analysis of materials composition, thermal and electrical performance, and mechanical design. “Most teardowns focus on some specific aspect,” Gorsch says. “We wanted a holistic comparison.”

This is the type of research that “helps researchers keep abreast of what’s happening commercially so they can target their early-stage R&D decisions appropriately,” says Micah S. Ziegler, who studies energy technology innovation at the Georgia Institute of Technology and was not involved in the work.