Actually, it's more like "hockey stick" growth, but exponential will be a suitable proxy.
My crystal ball? Battery costs. Battery costs have been falling at a very consistent 19% per year, and is forecast to continue this trend. Maybe you have a reason to believe this will not be the case, but with all the research going on in the battery world, I don't really see an end to this trend in the next 5 years.
Now so far, the cost savings on the battery side have not transitioned directly to cost savings on the vehicle. This is because automakers have focused on adding larger format batteries to address a perceived range limitation. But there have been significant increases in range over the past 8 years, while keeping the price constant. I believe that once we hit an affordable 300 mile (maybe 350) EV, that there will be little reason to keep adding more battery, and instead we will see a shift towards making vehicles more affordable. And eventually there will be a crossover point where the unsubsidized cost of an EV will be less than an equivalent ICE.
And at that point, to the buying public, it simply won't matter whether it's an EV or an ICE. That's the problem I have with people that are saying this or that about "EV demand". Most people are sticker-price focused. They don't necessarily care what's under the hood. They only care about what the sticker says. And the day the sticker on an EV is less than the sticker on an ICE, they are going to get the EV. At this point it stops being a ramp and turns a sharp corner.
Yes, EVs have to become available in the form factors they want. And yes, there will need to be education of the masses about how and where to charge their cars. But the growing number of EV owners are going to be the teachers. And the more EVs that people see on the road, the more people are going to be willing to ask their friends, neighbors and co-workers about them.
If you think any part of this "crystal ball" is wrong, let me know, but you'll be disagreeing with the technology adoption curve that has been repeated throughout history, so it's a tough argument to make. About the only legitimate difference of opinion we can have is the timescale. Yes, with falling battery prices, the percentage of the cost of the battery to the vehicle becomes smaller, so the gains in vehicle price become less significant. But I don't think this is going to take more than another 4-5 years. We now have 3 mass produces vehicles with ranges over 300 miles, with several more knocking on the door at 250 (unfortunately in somewhat limited quantities). 2020 should be a big year in terms of new EV releases. Once we get those vehicles with 300 miles on the market, we can start the process of driving the costs down.
I agree with almost all of this, except the bolded section. When people say they want/need a 300+ mile car, what they mean by that isn't a 300 or 350 mile BEV, before all the subtractions you need to know about and allow for as regards speed, climate, and degradation, but a 300 or 350 mile range like an ICE. Now, if you were to say 300 or 350 miles including all of the above at the end of the car's life, I'd agree with you, but we all know that requires a range at least 1/3rd and maybe 1/2 or more greater than the nominal range when new. The average age of the fleet is I believe now up to 11.8 years, so EoL battery range should be for at least 12 and probably 15 or 20 years.
I've done this calc for my own requirements. I need a car for roadtrips, and keep them until they no longer function (current car is 16 y.o. and still going strong). I've decided that for a BEV to be reasonably useful and cost-effective for me, at a minimum I want to be able to drive from home to Lee Vininga typical weekend trip, without recharging, a distance of 207 miles on freeway and highway, and which requires climbing from about 100 ft. sea level over 9,941 ft. Tioga Pass 193 miles out before descending 14 miles and 3,160 feet to Lee Vining at 6,780 ft., any time of the year and in any conditions when the road's open (which can range from late April to late Nov., but is usually less). I want to be able to do it for at least 12 years and prefer longer, jut as I prefer longer range and faster recharging. I want to be able to do it driving just as I do in my ICE,at the same speeds while freely using heat/AC as desired, and with at least a 30 mile reserve under the same conditions. Having played around with EV tripplanner, there's not a single BEV (including the longest-ranged Teslas) now available that can meet those requirements for that length of time
, although some of them can do the trip for part of the time and/or under more restrictive conditions. I've been fairly interested in the)a Kia Niro, but its ability to make the trip is questionable even when new, and would be impossible with degradation. That QCs will eventually be built along the way is true, but irrelevant to my needs, which include time limitations as well as flexibility.
By comparison, my 16 y.o. ICE can still do the trip to Lee Vining and return
un-refueled basically free of care, as it has essentially the same range as when it was new, and should I need to refuel it due to unusual circumstances I can do so lots of places in no more time than it takes to use the bathroom. I paid something over $24k cash for it out the door, including TTL, so BEVs have a long way to go before they can meet the same value/capability, even if QCing gets cheaper than gas, and even with the current high gas prices in California that's at best a marginal cost advantage over my 28-30 mpg real world hwy ICE, and still at a disadvantage compared to a moderately-high mpg HEV.
And that's just for my basic weekend trip, not the extended road trips that I want to be able to take again in a ZEV, which require even more range and even faster charging
So, while I agree with you that prices will only start to drop when the range is adequate, how much range will be adequate depends heavily on extending the guaranteed
, no worries EoL range of BEVs, and that currently requires such large, heavy and expensive battery packs that I don't see the cross-over point happening until sometime beyond the 4-5 years you suggest.