Kiskaloo,
I would expect the venting system would be designed for a more controlled release.
I would expect that, certainly. How quickly the pressure descent is ennabled would have serious repercussions: Not too quickly, the cells would rupture and make the problem worse, (far worse?). Too slowly, the pressure would build, risking the cabling penetrations and their integrity.
Malfunction? Disastrous. The EE Bay could be shredded in toto by the resulting release of highly pressurized gases and flaming fire... To involve the fuselage structure? There is no way to extinguish a structural fire involving CFRP....
Who shall design/build this system, Secure a Plane? Thales?
Who will test it? Will there be destructive testing? How long will it take? Is there a better choice of Battery instead?
Kiskaloo...forgive the nature of my post if it is too strong. BOEING have asked and answered these questions long ago. In that sense, you may consider them rhetorical in nature.
But since BOEING will not share their answers, perhaps a discussion, here?