Do you mean an expansion card or expansion bay? The expansion bay is only found on the Framework 16, and it’s located at the back, optionally housing the dGPU.
If you mean an expansion card, trouble is, a standard smart card is larger than the size of an expansion card. Though some community members have proposed an expansion card that extends slightly under the laptop in order to have a smart card side in just under the laptop.
While they would fit into an Expansion Card, there are two spots of bother:
The NVMe’s are fixed with a screw, the same way as the internal ones.
As I doubt the NVMe connector is actually designed to provide hot-swap capabilities, this could be actually a good thing, as it prevents the NVMe’s from getting damaged from said action.
The adapters include heat pads to transfer the heat to their metal casings… and when in use they get hot to the point where it’s unbearable to touch them. Of course, this varies by the actual NVMe you are using and its use case, but their threshold usually being at 70°C, you need to think about how to transfer said heat to avoid throttling.
Considering these issues, you are way better off using USB-C NVMe enclosures including passive (or even active) heat dissipation.
