The 2021 BYD e-Platform 3.0 brought quite a few changes to the battery pack design. Now with more data available it is worth a more detailed look. BYD make a number of claims around the battery in this design:
- integrated 8-in-1 assembly => Cell to Body design
- structural architecture
- high expandability of the e-platform 3.0 creates a larger axle-to-length ratio => A-class cars to D-class cars
- overall battery pack height = 110mm => lower height for overall body and battery package (10mm overall gain)
- lower body posture => ultra-low wind resistance
The platform is likely to be updated to 4.0 in 2024.
Cell Orientation
With the update of the battery pack design and integration the cell orientation has changed. Originally the cells ran across the pack from the left to right side (east-west). e-Platform 3.0 has changed this so the cells now run front to back (north-south).
Why make this change?
- longer cells => improved density => higher pack density
- BYD claim 10% improvement in energy density [1], this might be volumetric as the gravimetric gain is only 2.5%
- BYD Blade Pack (Han) = 144Wh/kg
- BYD e-Platform 3.0 (Seal) = 148Wh/kg
- BYD claim 10% improvement in energy density [1], this might be volumetric as the gravimetric gain is only 2.5%
- cell terminals more protected => improved side impact safety
- shorter overall cell stack => easier to support cell compressive forces
- vent paths easier to manage at front and rear of the pack => improved safety
BYD Blade Nail Penetration Test
BYD mention the nail penetration test in their literature and hence it was worth looking at this in-depth.
Cell to Body
BYD [1] list the benefits of this approach as:
- efficiency
- aerodynamics
- power
- body rigidity
- space utilisation
This post has been built based on the support and sponsorship from: MAHLE Powertrain Ltd, Thermo Fisher Scientific, Eatron Technologies, About:Energy and Quarto Technical Services.
The latest image for the BYD Seal U appears to show a very similar structural approach. Note: the image below of the Seal U has the lid of the battery pack removed. In the design the lid of the pack forms the floor of the body structure.
BYD show the battery being part of the overall crash structure. The front subframe appears to be aligned with the base of the battery pack. The flat rectangular battery pack is described as a “honeycomb structure”. The fact the battery pack is flat, 110mm in thickness and the cells are bonded into the structure means that this is an extremely stiff structural element. This is reflected in a body torsional stiffness of 40,500 Nm/degree.
Charging
e-Platform 3.0 uses the motor inductor to replace the boost inductor in the original boost solution, to meet the 420-750V voltage range of charging piles with high-power DC charging.
References
- BYD SEAL Dynamic and Intelligent, BYD
- BYD Seal U, BYD EU
- Why is BYD’s e-Platform 3.0 so special?, BYD
- BYD Seal Review, AutoCar
See also: BYD, Battery to Vehicle Mechanical Integration, Battery Heating, BYD Battery Self Heating System