This may be a very random question. Just out of curiosity's sake, I have seen a few videos where some guys get a battery pack from a wrecked leaf, reconfigure all the cells, put them all in the trunk of their current leaf, and splice it into the main power cord in the car. I would NEVER attempt this.
However, it did make me wonder - why don't Nissan and other manufacturers offer extra 'plug and play' suitcase sized batteries that you could plug in to the car and extend the power available to the car by 10 or so KWh? Like if there was a special plug in the trunk. You would only use them when you are going on a long trip, otherwise they sit in the garage.
This would offer an extended range without having to offer a whole other longer range model. Also the owner would not be lugging around extra capacity that they would only use 10% of the time. If it was parallel to the main battery it would not increase the voltage, just the available amps.
I'm not an engineer, so I may very well be missing something. Would this not be a feature that would be relatively simple to do?