Identify your pack version: Decoding Your Tesla Battery Pack VersionI'm not spotting anything about a redesign?
The change happened when Tesla released the new 90kwh (compare to the old 90kwh that is used until early 2014). This guy's understanding of the versions is correct but he didn't know the change in arrangement and cooling. If you open the pack, you will notice the difference in the arrangement and cooling tube configuration. I couldn't find a video of an early model pack on youtube right now but if you can compare yours with new 90kwh pack videos.
on battery pack collision: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S, this is an external thing that is not previously installed in some early vehicles.
Also, there was a software update on the radiator of the BMS in 2015 to improve fan performance.
Correct me if I am wrong