The leaders in the electric vehicle battery market are understandably coy about what happens inside their batteries. Tesla dominates the North American and European markets. While BYD leads in its homeland, China. We report on a new study that exposes the difference between Tesla and BYD batteries, for all to see.
Delving Into the Differences in BYD and Tesla EV Batteries
Scientists at Aachen University in Germany, decided to examine Tesla 4680 cylindrical cells in detail. And then compare them with their competitor BYD’s cylindrical cells. They obtained samples of each of these products, and did a tear-down analysis of their design and performance.
The Aachen University results appear in the March 6, 2025 edition of Cell Biomaterials Journal, that we link to below. Their headline findings are as follows, as summarized by Science Blog:
- The Tesla batteries prioritize high energy density and performance.
- The BYD batteries prioritize volume efficiency and lower-cost materials.
The Aachen University team compared battery size and mechanical structure, before delving into electrode composition, and thermal and electrical performance. In the end they concluded that the BYD battery was more efficient, in the way it implemented thermal management.
Interestingly, the researchers found no evidence of silicon dioxide in either of the Tesla 4680, or BYD cylindrical cell graphite anodes. This is an interesting anomaly, which ignores the current trend of using silicon to increase density.
Different Designs Lead to Different Battery Performance
The report by Aachen University in Cell Biomaterials Journal, cites variations in the speed with which the two batteries charge and discharge. It also notes marked differences in battery assembly, as confirmed by Science blog:
- BYD secures the electrode sheets in a stack, that laminates the edges of the separator between the anode and the cathode.
- Tesla also uses a novel binder, in this instance a substance that holds the active materials in the electrodes together.
Both these strategies are a departure from the methods used by most other manufacturers in the battery industry. The practice of connecting thin electrode foils with laser welding (instead of ultrasonic welding), is another departure from the norm in the Tesla and BYD batteries.
More Information
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