(PDF) Investigative Update of Battery Fire Japan Airlines B-787 - Jan 7, 2013

I find it difficult to understand why Boeing would allow the entire future of the 787 to be jeopardized by two small batteries. After all of the state of the art engineering that went into the 787 are we now to remain grounded over a battery?

I will be honest, from the photos of the battery pack, it contained the cells a lot better than imagined. That's what makes it so hard for armchair engineers.

I also wonder if Japan's investigators have found the same results from their examination of the battery pack?

I had assumed that the battery being called "lithium ion" in the press was actually a lithium ion polymer battery. That distinction is that there is no liquid electrolyte sloshing about in the cell of a polymer battery. The 787 battery is airborn vibrating in flight for hours as well as rapidly accelerating and decelerating. No wonder holes are blown through the seperator walls. Not to mention the separator is less than one ten-thousandths of an inch thick! How can you make a material that thin to any meaningful tolerence?

You need to build a containment device that will contain the propensity of the materials in the 787 design to catch fire. It appears the drive towards lighter and smaller neglected that little tidbit as evidenced by the picture of the battery that failed. One should also have a reservior to contain liquid electrolyte forced out of the rupture valves rather than spewing flaming hot material all over the electronics bay.

The bay itself looks like there is a bit of space left for a larger, safer battery. Perhaps a back-up unit too.