SEATTLE — Boeing will propose to regulators, perhaps this week, a short-term fix to bolster the 787 Dreamliner’s defenses in case of battery fires like those that have kept the jet grounded the past month.

The goal is to get the planes flying again, according to multiple sources with knowledge of the matter, while Boeing works on a comprehensive redesign of the lithium-ion battery system that could take nine months or more to implement.

The interim fix includes a heavy-duty titanium or steel containment box around the battery cells, and high-pressure evacuation tubes that, in the event of a battery fire, would vent any gases directly to the outside of the jet.