Toyota USA
4 HN mentions · mentioned in 4 months, 2021–2024
3:20 · 122K views · Mar 14, 2016
Toyota's short promo clip showing a Mirai carbon-fiber hydrogen tank shot with a .50 caliber round at point blank range. The bullet pierces the tank, which does not burst, and the gas simply escapes and disperses.
Cited in hydrogen debates as evidence that pressurized hydrogen tanks do not necessarily explode when punctured.
4 comments from Hacker News
While I do not argue the explosive nature of it, safety can be improved by embracing how fast it disperses. Think Toyota went that path with interleaved fibers in their containers' outer enclosures, to augment that effect, so it isn't sufficient for an explosion to occur. this video (Edit: added Toyota's test where they shot an hydrogen tank, you can see the fibers and the gas dispersion)
Here's a video released by Toyota where they shot a hydrogen tank used in the Mirai with a 50-caliber bullet [1]. The bullet pierced the tank, but it didn't go kaboom. The hydrogen just leaked out. Now personally I think that a hydrogen leak could also be very dangerous. But so can a gasoline leak or a lithium ion battery if exposed to the air. [1] this video
A catch is that hydrogen does become much safer in high-pressure tanks, because, when such tanks are breached, hydrogen escapes so fast that it can't react with oxygen fast enough to burst into flame. To prove this, Toyota literally shot their hydrogen tank with .50 cal[1]. [1]: this video
Here's a video of someone breaching a full hydrogen fuel cell with a bullet. No explosion because it comes out too fast. this video