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On July 13 I gave a talk to the San Diego Electric Vehicle Association. It was a virtual talk and I covered the topic of Modular Battery Swap. Here is a link to the Youtube of the talk.

Recently I have come to realize another major problem with the Fast Charge model for vehicle refueling as technology progresses, and this is not really covered in my book. What I'm going to say here should provoke some thought and alarm about the push for DC fast charging we are spending billions and billions of dollars on, but here goes anyways. 

"With more advanced, smaller batteries the Fast Charge times will actually slow down, not get faster"

Here is why. As the battery technology improves (and it will) we will see the battery size and weight decrease by a factor of 6 to 10 times. The physics and chemistry exist for this today - and when there is money to be made, history has proven we will get there. With this in mind, the problem for DC Fast Charge is quite simple - HEAT!  A smaller lighter battery will still require that it be charged at several hundred Kilowatts to be fast enough to be practical, but we will see that its temperature is going to rise uncontrollably. This is because of its Thermal Mass being 6 to 10 times smaller. Simply put, it is quicker to boil a cup of water on your stove than a large pot of water.

OK, so we could solve this by keeping the batteries the same size as they are now - but, we need these smaller batteries for numerous other reasons. Smaller will always be best for cost, sustainability, and efficiency. Modular Swap of course will not have this "heating" problem since the batteries are charged slowly away from the car. And aside from this, performing the swap will get much easier than today since the batteries will weigh 6-10X less and will be that much smaller in size. Modular Swap will guarantee future-proofing.