Tony: One thing worth noting is that 45C isn't the ambient temperature for testing. That is the constant, internal battery temperature during the testing, which is more severe than temperature cycles that heat up and cool down.
Yes, we all agree about the 45C battery temp... hopefully, you also understand that a 45C battery can be in a 35C ambient temperature parking lot in Phoenix. At 45C ambient, that same battery can be at 55C.
What happens when we charge it? It heats up further.
One tidbit from my aviation background... testing tended to max out at 50C, and therefore performance data ended there. I have been stopped from operating in the USA by that temperature threshold; can you guess what city?
Folks driving their LEAF aren't going to be constrained by FAR Part 121, and will drive regardless of the temperature.