Elon Musk, head of SpaceX Company, said the lithium-ion batteries used in the Dreamliner are “inherently unsafe”, however,  this is the battery The Boeing Company (NYSE:BA) chose for its plane. Musk, who also heads Tesla, a company which uses lithium-ion batteries in electronic cars, said Boeing concentrated the battery power in a number of large cells located in close proximity to one another, instead of dispersing the power among smaller, but more widely separated cells.

Boeing 787

According to Musk, when thermal runaway occurs with a big cell, comparatively more amount of energy is released and it is not easy to prevent that energy from heating up the other nearby cells and causing the domino effect, because of which fire can break out in the whole pack.

The Boeing Company (NYSE:BA) have not been able to find the real cause of the mishap which occurred few months back. What Musk has suggested could be valid, but Boeing will only be able to resolve the issue if it comes out confident and clear on the real cause.

“Unfortunately, the pack architecture supplied to Boeing is inherently unsafe,” writes Musk in an email to Flightglobal.

“Large cells without enough space between them to isolate against the cell-to-cell thermal domino effect means it is simply a matter of time before there are more incidents of this nature,” he adds.

Like Boeing, Tesla electric cars are also fitted with batteries fueled by lithium-cobalt oxide, which is one of the most flammable chemistries of lithium-ion batteries on the market. The Boeing Company (NYSE:BA) resorted to using the battery with a grouping of eight large cells, whereas Tesla batteries have thousands of smaller cells, which are separated and independent to prevent fire in a single cell from causing any damage to the surrounding cells.

The battery Tesla uses, is an aerospace-capable version, and was been designed to fit SpaceX’s Falcon 9 space launch vehicle. SpaceX is a competitior to Boeing/Lockheed Martin Joint venture United Launch Alliance for customers. Boeing is not in a mood to take any assistance from Tesla and SpaceX, and has declined the offer, according to Musk.

“They [Boeing] believe they have this under control, although I think there is a fundamental safety issue with the architecture of a pack with large cells,” writes Musk in an email. “It is much harder to maintain an even temperature in a large cell, as the distance from the center of the cell to the edge is much greater, which increases the risk of thermal runaway.”

The Boeing Company (NYSE:BA)’s commercial reputation is being hampered due to its incapacity to pinpoint the cause behind the Dreamliner’s battery fire incidents. For the time Dreamliners have been grounded as the investigation is being carried by US National Transportation Safety Board. Japanese, as well as US authorities, are examining the batteries and trying to figure out the reason for the mishap.

Earlier this week, National Transportation Safety Board (NTSB), released its fourth update regarding its investigation on a Japan airlines plane that caught fire. As per the report, that plane logged 169 flight hours with 22 cycles when two of its lithium ion batteries caught fire. The report identified GS Yuasa as the manufacturer of the auxiliary power unit battery used in the Boeing 787.