Technology: Back to the Electrics

Only one major roadblock has prevented Detroit’s auto engineers from turning their nostalgic dreams of an electric car into a practical scheme: lack of a battery with the capacity and durability to power a modern automo bile. Now that obstacle may have been removed. Ford Motor Co. scientists have demonstrated a miniature version of a new battery that promises to put the company in the electric-car business within the next ten years.

Unlike the traditional auto battery, which contains solid lead and lead dioxide electrodes in a liquid electrolyte of sulphuric acid, the new Ford battery uses liquid sodium and liquid sulphur for electrodes and a novel ceramic electrolyte made of aluminum oxide. In the battery, electric current is produced by separating the sodium and sulphur with the ceramic electrolyte, which blocks the passage of all particles except sodium ions (sodium atoms stripped of one of their electrons).

Strong Attraction. Unable to reach the sulphur atoms to which they are strongly attracted, the sodium atoms each give up an electron to become sodium ions that are able to pass through the ceramic. The extra electrons, having no other way to rejoin the ions, flow through an external circuit that carries them to the sulphur electrode. That electron flow is an electric current.

Another two years of development will be required, Ford estimates, to produce sodium-sulphur batteries large enough to power even the smallest compact cars. Such batteries would weigh about 300 lbs., produce about 10 kw. of power, and store 15 times as much energy as lead-acid batteries. Equipped with the new batteries, two prototype electric cars that Ford is now building in England are designed to travel 150 miles at 40 m.p.h. They will weigh 1,100 lbs. and carry two adults and two children. Because electric cars require no transmission, radiator, fuel tank, carburetor, fuel pump, exhaust pipe or muffler, the increased weight of the batteries will be easily absorbed.

Shorter Range. There are still problems to be solved, however, before the new electrics take to the streets. Ford’s battery must be heated to about 500° F. to keep its sodium and sulphur electrodes in liquid form, a temperature the company believes can be maintained by effective insulation of battery cells and by frequent charging. Care must also be taken that the battery’s sodium does not come into contact with water; the combination produces highly inflammable hydrogen gas.

Because of their shorter range and limited rate of acceleration, the new electric autos will probably be restricted to brief low-speed trips in metropolitan areas—where they are actually needed most to cut down on smog and street noise. For high-speed urban expressways and intercity highways, a Ford spokesman readily concedes, the more muscular internal-combustion engine “will be the most practical form of power for some time to come.”