The BMW i7’s solid-state battery prototype uses a lithium-metal anode that’s so chemically reactive it requires the entire battery pack to be hermetically sealed in an inert argon atmosphere during assembly, meaning if a manufacturing seal ever failed during operation, the battery would spontaneously ignite from moisture exposure alone—forcing BMW engineers to design redundant sealing systems within sealing systems, essentially building a battery inside a battery just to prevent catastrophic thermal runaway from atmospheric contamination.
Car Fact #79 — September 3, 2026
