PEM Analysis of Tesla and BYD Batteries Delivers Surprising Results
The Chair of Production Engineering of E-Mobility Components (PEM) of RWTH Aachen University has disassembled current traction batteries from Tesla and Chinaʼs leading electric vehicle manufacturer BYD to compare the two batteries with each other. The results published on March 6th, 2025, in the Cell Reports Physical Science journal reveal that Teslaʼs 4680 cells focus on high energy density, while volume efficiency and more cost-effective materials are more important for BYDʼs blade cell. According to the study, BYDʼs battery is more efficient because it enables simpler thermal management.
PEM Director Professor Achim Kampker, says:
Both players have only ever revealed little data about their batteries, so the cellsʼ mechanical structure and most of their properties have remained hidden to date,
In general, there is little detailed data and analysis on modern electric vehicle batteries, according to the RWTH institute. The researchers therefore investigated the cellsʼ mechanical construction, dimensions, and electrical and thermal properties as well as the exact material composition of their electrodes. They also determined the cell materialsʼ costs and the processes used for their assembly.
PEM Management Member Professor Heiner Heimes, states:
We were surprised that there is no silicon in the anodes of both batteries – especially in Teslaʼs cell, as silicon is widely regarded in research as a key material for increasing energy density,
Unusual process step for BYD battery
The researchers also found that the two “highly innovative” and “fundamentally differently designed” battery types show significant differences in the speed at which they can be charged or discharged in relation to their maximum capacity. According to the study, BYDʼs blade cell is based on a special method in which the anodes and cathodes in the electrode stack are fixed in an ideal position in relation to each other by laminating the separator edges. The Tesla battery, meanwhile, uses a new type of binder that holds the active materials in the electrodes together. However, the batteries also had unexpected similarities: their thin electrode foils were joined together using laser welding, which is still unusual, instead of the ultrasonic welding commonly used on the market.
Kampker, says:
Although BYD’s cell is much larger than Tesla’s, the proportion of passive cell components such as current collectors, housings, and busbars is similar,
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PEM Analysis of Tesla and BYD Batteries Delivers Surprising Results, source
