Europe's safety authority has been wrangling with its own certification process for lithium-ion battery technology, after it was forced to rethink a new proposal just weeks before the 787 grounding.
The European Aviation Safety Agency put forward a revision to its electrical systems certification documentation in May 2011.
It proposed creating an entirely new section for lithium-ion and lithium polymer battery installation given the susceptibility of cells to ignition and thermal runaway.
EASA's draft demanded that safe cell temperatures and pressures be maintained during charging and discharging, and that battery design must preclude self-sustaining, uncontrolled increases in both.
It also required monitoring and warning features to alert the crew over the state of charge, and procedures for capacity measurement and maintenance.
But EASA withdrew its proposal mid-November 2012, citing a "lack of maturity" for the revision as well as "discussions presently occurring in the frame of standardisation bodies".
"It has been concluded that the proposed amendment needs to be reviewed in the light of these developments," it stated. "The agency will make a new proposal once this item matures."
EASA had reviewed comments from various entities including the US FAA, which suggested the proposal needed revising to cover all lithium batteries and chemistries.
Airbus is intending to use lithium-ion batteries for its A350 but is confident that it will not have to amend the electrical architecture.
But the aircraft is not designed to be as broadly dependent on electrical power as the 787, with overall power requirements of 550kVA - about a third that of its rival.
Airbus chief Fabrice Brégier says the airframer held discussions with certification agencies over its plans to use lithium-ion batteries. "They seemed happy with the selected architecture of the aircraft," he says.
He says the airframer is "confident" that the A350's electrical design is "robust" and that there is no reason for it to be similar to the 787's.