Chinese media are reporting that an electric bus caught fire in Shanghai at noon on Monday.

And this is apparently not the first such incident. A Reuters report indicates that at least one earlier incident has been reported in the Chinese press within the last three months.

A local Shanghai blog, The Shanghaiist, showed photos of the burned bus.

Reports conflict as to whether the bus was in service, or stationary and parked by the roadside, but no injuries were reported.

The bus is one of a test fleet that uses ultra-capacitors to store energy from a network of charging points that top up the bus during stops to pick up passengers.

Challenge Bibendum 2006 - Electric Bus Recharging

Challenge Bibendum 2006 - Electric Bus Recharging

Buses that use ultra-capacitors are fundamentally different from electric cars sold in the U.S., including the 2011 Chevrolet Volt and 2011 Nissan Leaf, which store energy in lithium-ion battery packs that charge at much slower rates.

Those vehicles do not use ultracapacitors, which do not store nearly as much energy but can deliver very high power very quickly.

Some quick back-of-the-envelope calculations indicate that the ultracapacitors may recharge at 182 kilowatts, far quicker than any electric car on the market.

At a 65-percent efficiency rate, 60 kW or more of heat may be shed during recharging--a substantial amount.

Electric cars, on the other hand, charge at 3.3 or 6.6 kW on dedicated 240-Volt Level 2 charging stations (usually mounted in garages), or a maximum of 50 kW at the few Level 3 DC Quick-Charge stations.

Still, the incident may rekindle fears both of the safety of electric cars and the quality standards of Chinese-made vehicles. Few, if any, of the Ultra-Capacitor buses are in use outside the country.

[Reuters, Shanghaiist; photo from Eastday]


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