Andrea Rothman, in a post for Bloomberg:
“It suggests that Airbus thinks that the Li-ion problems could be intractable or at least take too long to fix to avoid the risk of inducing delays in A350’s entry into service in late 2014, so that suggests what everyone probably already realizes: this is a difficult problem and could take some months to resolve,” said Nick Cunningham, managing partner at Agency Partners LLP in London.
Airbus is making a smart move here. It remains to be seen how Boeing's issue with lithium-ion batteries on the 787 will be resolved. Switching to the more typical cadmium batteries is a sensible way to ensure that the behind-schedule A350 will not be further delayed by regulatory approval concerns surrounding lithium-ion batteries.
However, there is a price to be paid for this change. The primary reason that Boeing chose lithium-ion batteries is the fact that they pack a lot of power into a very small and lightweight space when compared to cadmium batteries. By switching to cadmium batteries, Airbus is adding over 200 pounds of extra weight to the A350 design. A big selling point for modern aircraft such as the 787 and A350 is fuel efficiency, which is partly obtained by lower weight than previous aircraft designs. In this case, every pound of weight savings is necessary. Adding that much extra weight will not make it easy for Airbus to meet its efficiency guarantees.