Bad Battery Design Behind Boeing Dreamliner Groundings

So an expert says

A charred lithium ion battery at the center of the worldwide grounding of the Boeing 787 Dreamliner showed evidence of "thermal runaway" -- which is indicative of a design problem, experts tell FoxNews.com.

The All Nippon Airways plane made an emergency landing Wednesday morning in western Japan after its pilots smelled something burning and received a cockpit warning of battery problems. Nearly all 50 of the 787s in use around the world have since been grounded.

The battery's burned insides indicate it operated at a voltage above its design limit, a Japanese investigator said Friday. That's a clear sign of an out-of-control chemical reaction, explained Reginald Tomkins, a professor of chemical engineering at New Jersey Institute of Technology.