Some industry experts are not too hot on the electric car battery swap plan, like the one envisioned by Shai Agassi:

The latest skeptic is Thomas Weber, Mercedes chief of research and development. In today’s Ha Aretz, an Israeli newspaper, Weber said that battery-swapping stations for electric cars may, in fact, be dangerous. The Mercedes executive said his company explored a similar plan in the 1970s, and discovered that changing a battery on the road could cause electrocution or fire.

In 1972, Mercedes built an electric bus called the LE 306. The vehicle was limited to 40 miles of range but, according to a company press release, the battery could be replaced using a “push-through horizontal-exchange technology.” The release promised that the process, mostly manual, would take the same time as a fill-up at a gas station. Eighty-nine prototype vehicles were built and the battery swapping system was “extensively tested,” according to the company.

The basis of the critique from Mercedes is very different from others. Most notably, Mercedes is saying that even with a proprietary and closed system they found it not feasible with 1970s technology. Apparently even modern technology would be insufficient. The idea that it could cause a fire is neither here nor there since gasoline stations can and do cause much more dangerous fires. Others point out that the lack of standards between car makers would make swaps impractical. Imagine if every car required a different fuel pump. That seems like a more significant obstacle.