The Road to Solid-State EVs — Part 4
By Jim Ringold
This is the fourth and final in a series looking at the advancements in “solid state” devices that were required to make electronic vehicles (EVs) practical and affordable for everyday use. The first three parts are available on CleanTechnica and cover: the invention of discrete (individual) transistors by Bell Labs; the integration of numerous discrete transistors into individual solid-state devices; the integrated devices Tesla uses to operate an EV from a central, redundant computer.
Direct current (DC) power from a battery needs to be converted to alternating current (AC), which powers your home, to power the electric motor(s) that power your EV. AC can have its voltage changed by using a transformer (an extremely logical name) to do the job.
Transformers have windings into two coils (fields) of wire wrapped around an iron core. The number of windings determines if the voltage increases or decreases. The amperage (the amount of volume vs. voltage pressure) also changes and is important, but beyond the scope of this explanation. DC only flows in one direction and cannot create a field to allow for an alternating current transformation. Therefore, a solid-state device known as a DC-to-DC converter was developed. A rather complicated process of converting one DC voltage to a different DC voltage requires changing DC voltage to AC voltage, then transforming it and converting back to DC. This is performed quite well by solid-state devices. First accomplished at low voltages, improved high-voltage DC-to-DC converters (DC/DC) were created that were suitable for use in EVs.
The various “solid state” components have matured in power handling, reliability, and cost to make an EV possible, not just a high school science project. Of course the other vital components include the lithium-ion battery and a suitable environment in which it could live a reasonably long life. It was enjoyable to demonstrate to your friends your early Tesla and watch their look of disbelief when you explained it was powered by thousands of almost “AA” size batteries just like those in their laptop computer. But that is a whole other story!
An awful lot of stars had to align to make all of this possible. Elon Musk and his associates used those aligned stars to place all the right technologies into a small British roadster, and they were then off to the races. Some of those early Tesla Roadsters are still running today, a tribute to the original solid-state devices and configurations those innovators developed.
We are describing what happened roughly between 2008 and 2012. By way of comparison, let’s drop back to 1996. That was the year the GM EV1 electric car rolled off the assembly line. Less than 10 years prior to the Tesla Roadster, GM had created the mother of EVs. The EV1 clearly demonstrated the corporate abilities of GM at that time. Its development originated back in the 1980s. GM had a subsidiary by the name of Hughes (as in Howard) Aircraft to help with the necessary technologies. Some of the aging giants of GM management contributed to the EV effort.
There is a GM EV1 running around my hometown now in 2021. The owner says the zero-to-sixty time is about 8.5 seconds, with a top speed of 80 mph. The car is spotless and the owner proudly explains that it still has the original lead-acid batteries. A rare bird for sure!
Let’s go over the GM EV1 specifications in comparison to the Tesla that came a decade later: The EV1 had a range of 70 to 90 miles depending on how fast you were driving. The battery pack consisted of 26 12V lead-acid batteries (same as an ICE car starter battery) wired together to produce 312 volts. It had a weight of about 1,200 pounds. This was about a third of the total weight of this slim and very aerodynamic two-passenger EV. Charging time was 8 hours for the 80 mile range. Replacing the batteries would approach a third of the cost of the car. In short, the lithium-ion battery had to become available to perfect a really practical EV.
In addition to the 1996 price of $35,000, the EV1 needed a $7,000 Hughes charger if you wanted to cut the charge time to 4 hours or so. About 1,100 of these slim, little cars were built. GM decided that the EV1 cars were to be leased through Saturn dealerships (which are now all gone, of course). When the leases were up, GM demanded in 2003 that the EV1s be returned. There was a conflict in that GM was busy selling internal combustion engine cars and here was the EV1 showing that there was strong consumer interest in an EV. The EV1s that GM got back were crushed! Good PR was crushed right along with the EV. But it is easy to imagine a lot of GM folks who had birthed this early EV were crushed as well.
Will future battery achievements make today’s EVs look as obsolete as the GM EV1? Time will tell. But it is likely they will. Fun times at the beginning of potential domination by EVs.
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