Let's square off rapid battery exchange against quick charging and get this sorted.
Keep in mind that there is no reason not to include a jack on an ALE vehicle (Autonomous Linear Exchange)
so that it too can be plugged in.
Rapid Exchange is better than quick charging for more reasons than simply convenience (20 seconds autonomously vs. 25 mins on a cable), so please take a look at the following facts and form your own opinion.
1. Most importantly it truly facilitates an affordable EV for mass consumption. The battery pack is by far the most expensive aspect of the vehicle and accounts for the considerable price difference from combustion powered cars. So what if we cut the packs in half, left one in the car to power it while the other charges, and facilitate exchanges that are less inconvenient or even noticeable than stopping at a red light? Then realize that 70% of electric vehicles on the road will not require an exchange or quick charge every day, so the cost of that "extra pack" is divided among many vehicles, and actually fluctuates around one for every four vehicles. Beyond this scenario, which is accomplished with today's technology, what if we can make the batteries outlive the cars?
2. Rapid exchange creates a new engineering direction because it separates the vehicle from the pack. So now we can focus on making the batteries last as long as possible as opposed to charging as fast as possible. Then we can design packs that outlive the cars they serve, and we will see the end user cost drop below that of even one 50kWh pack! New technology involving nano-wire construction with certain plating materials have not yet died in the laboratory, like this.
The battery becomes the conveyor of power to the car, and not a part of the car. How we design it, build it, use it, and recycle it will all change as this new paradigm is realized.
3. Owners don't have to worry about pack degradation half way through the life of the vehicle and how their quick charging habits affect its lifespan.
4. Rapid exchange gives you a 100% charged pack in 20 seconds as opposed to an 80% charged pack in 25 minutes with quick charging. Right now spotlight automakers are claiming range based on a 100% charged pack and then in the very next sentence telling the consumer they can charge it in 25 mins! Neither statement individually is false, but the two together...
5. Rapid exchange is favored by the utilities, because the grid cannot sustain mass consumption of quick charges. Each quick charge is equivalent to an entire neighborhood (120 houses) popping up at that site for the time the energy is being consumed. This is not to say that rapid exchange is non-taxing to the grid either, but that it is far less taxing. The inconvenient truth for quick charging is that the faster electricity is pushed the more heat and loss is generated. So while nominal values suggest parallels between the two methods as far as kWh/time is concerned, the loss factor is double with quick charging. An ALE strip capable of producing a 100% charged 50kWh pack every 15 minutes will draw 60kW, while a quick charger able to fill a 100kWh pack to 80% (80kWh) in 25 mins will require a minimum of 125kW. The challenges that lie ahead for the utilities are not enviable, but making better holistic choices within the auto industry now will help a lot.