From all the articles written gains an understanding of a paradox on the electrical systems fault of battery vs electrical current. What has been discovered is:
· Some voltage irregularities in its battery charging.
· Internal electrical shorts occurring in its battery
· An understated fire protection, and exposure of gaseous discharges, compromising hull atmosphere existed.
· Lack of diligence for its battery production and testing.
· No known causal listing of how a battery fails under operational tasks.
At this point Boeing can only break down the system in a series of controls that isolate probable causes for a failure. Establish a safety protocol for an unknown cause, but towards eliminating known risks within the electrical system and Lithium-Ion Battery performance.
So, without knowing causal steps towards for: run away instability, fire, and overheating, Boeing remains stumped on quantifying a solution specifically for the Lithium-Ion battery’s melt down. All those flights and cycles made without an incidence, then bam, two hot batteries within a short space of time.
Boeing has to review the age of the affected system, cycles and parts through its parts batch numbers. Any anomaly from parts production on those aircraft can trace back to origin. They are now past that phase of the investigation. Then they looked at the charging unit and any factors that contribute to the Lithium-Ion battery health, as its charging unit inputs or discharges through voltage regulation.
Boeing determined an occasional spike from the charging unit, could contribute to degradation of the battery health by creating the possibility of electrical shorts or fault at battery cell level. This could continue to strain the battery as more shorts continue to occur, and the demand increases on the healthy cell area of the battery.
The operational range of the battery is compromised with these “shorts”, and leads to an overheating battery, discharging heated gases and finally fire. No one can absolutely confirm this type of battery failure with these progressions, while under its operational load. Boeing now has monitoring of a battery’s thermal load and efficiency skewed towards thermal values which would indicate a degrading battery function is occurring from shorts. The front line of Boeing’s robust solution is at the factory level of:
· Checking it twice before leaving the factory floor.
· Voltage range regulation having tighter low and top range numbers where no anomaly can pass affecting cell integrity from shorts and a depletion of its cellular performance, which would cause a heat, gas fire condition.
· Securing the battery from heat propagation from cell to cell under failing conditions.
· Denying fire its oxygen.
· Containing the battery in a sealed stainless steel fire proof enclosure.
· Venting deadly gases over board.
The first two bullets are for chasing unknown rainbows of cause, and taking on these measures could be the simple solution. By not ever having a fire/heat/gas problem again, would suggest somewhere in there was the problem and the solution.
If Boeing never has another fire in that area over the next million or so hours, then they guessed correctly with solid assumptions. If “they” somehow, missed the mark on those two bullet point, then they have a robust safety containment system that will get everyone home safely.
Boeing has given the FAA, NTSB and others this assurance, techno paper, and its best effort for a resolution. The FAA will test the assumptions and logic as a valid substitute in place knowing causal factors. The containment and safety systems makes root cause a moot point.