Tank Safety: Hydrogen Tank Gunshot | Toyota
Why Hacker News recommends it
Cited in hydrogen debates as evidence that pressurized hydrogen tanks do not necessarily explode when punctured.
What it is
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.
Recommended by 0 HN commenters across 0 different months, 2021 to 2024.
What Hacker News said
Cites Clubber · 2021-07 · on “Toyota is quietly pushing Congress to slow the shift to electric vehicles”
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]
Cites freetime2 · 2023-02 · on “Seawater split to produce green hydrogen with nearly 100% efficiency”
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]
Cites esjeon · 2023-08 · on “Israeli Researchers Produce Green Hydrogen with 90% Efficiency”
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]
Cites spookie · 2024-01 · on “Hydrogen Cools Well, but Safety Is Crucial”
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)