The phrase “design for manufacturability” takes on new relevance for Boeing as they offered up their latest solution to solve the 787 Dreamliner’s lithium-ion battery woes.
According to the New York Times, the fixes require quite a bit of re-working, in that the proposed Boeing solution now involves a titanium venting system and steel box that would add 150 pounds to the weight of the plane – which may eliminate the weight savings from using the lithium-ion battery in the first place.
That solution comes as a result of what many believe to be the root cause of the battery failures – that too much energy generates too much heat, and the battery lacks an effective cooling mechanism to help dissipate the energy.
In other words, “it’s very possible that [the battery] could heat itself to the point at which it would burst into flames,” said Donald Sadoway, an MIT professor and battery researcher, as quoted in this article.
But what if something else entirely is causing the battery issue?
Norman Chow, president of Kemetco Research, suggests that, “as the largest battery component, the manganese supplied needs to be without metallic impurities, or can potentially contribute to thermal runaway (the overheating of Li-Ion battery materials leading to possible fire or explosion).”
Chow goes on to say that these impurities, at the part-per-billion level, are “known to cause an unacceptable number of batteries to experience thermal run-away in rechargeable Li-Ion batteries.”
We discussed this theory with Larry Reaugh, CEO of junior mining company American Manganese, who explained the issue this way: “The current process used to mine the manganese involves heavy crushing and grinding with heavy steel bodies [ed. note: this is referred to in the industry as grinding media] and big batteries contain 500 to 1,000 cells…the more cells you add, the greater the potential you have to get a particle of metal that could penetrate the membrane and create a short.”
American Manganese has collaborated with Chow at Kemetco to bring to market a different type of process – one involving hydrometallurgical processing.
The conventional EMD (electrolytic manganese dioxide) process involves high-temperature roasting. These high temperatures require lots of energy and tend to work for high-grade manganese only; or, said differently, the economics of this energy-intensive process only work for higher-grade deposits.
The hydrometallurgical process, on the other hand, eliminates the crushing and grinding, which lowers the risk of impurities during the remainder of the processing stages.
In the case of Boeing’s proposed battery fix, according to Donald Sadoway, “the approach seemed to focus more on dealing with battery failure than preventing [it].” Perhaps the aerospace industry can glean something from the automotive sector, which is, on the whole, more advanced in the realm of battery technology.
Do Kemetco Research and American Manganese have a plausible theory on the lithium-ion battery failures? They obviously have a vested interest in putting their theory forward, so what do MetalMiner readers think?
Leave a comment and let us know!