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I'm surprised their battery technology isn't just a tank of hydrogen that's shaped like a normal EV battery.
by zactato 3y ago
I'm surprised their battery technology isn't just a tank of hydrogen that's shaped like a normal EV battery.
- willmadden 3y agoIt would have terrible range with the same footprint. Hydrogen has great energy density by mass but terrible energy density by volume. The tank needs to be huge (but it would be light).
- _hypx 3y agoHydrogen has a higher energy density by volume compared to a li-ion battery. People really need to check their fact here.
- willmadden 3y agoI meant compared to gasoline.
- fragmede 3y agoHydrogen is a gas, which expands or compresses to fill all available space, so its density varies. People really need to check their understanding of physics here.
- Alupis 3y agoI would assume, but perhaps be wrong, that it would be liquid Hydrogen pumped into a vehicle's tank, and much like a tank of propane, the liquid expands back into a gas as pressure decreases (due to consumption). Hydrogen vehicles have the advantage of being refillable in minutes, much like petrol based vehicles - yet the only byproduct is water vapor, making them completely environmentally friendly. Hydrogen is also hugely abundant, and renewable in the sense that the water vapor could theoretically be split again via some other process. I would really like to know more about why Hydrogen vehicles did not take off as much as electric. They seem superior in many ways. My guess would be the chicken and egg problem - few Hydrogen refilling stations nation-wide vs. you can plug in at home and charge for 18 hours or whatever.
- blacksmith_tb 3y agoToyota does sell the Mirai[1] in California, it has pressurized tanks[2] I think keeping the hydrogen liquefied would take low temps as well, which would use a lot of energy for refrigeration (and or a lot of volume for insulation). 1: https://www.toyota.com/mirai/ https://www.toyota.com/mirai/ 2: https://en.wikipedia.org/wiki/Toyota_Mirai#High-pressure_hydrogen_tanks https://en.wikipedia.org/wiki/Toyota_Mirai#High-pressure_hyd...
- Alupis 3y agoThanks for the links. I had thought the Mirai was discontinued, but it looks like it's still in production. Regarding the tanks - they appear to be high pressure, but non-refrigerated and non-insulated. It would seem pressure alone keeps the Hydrogen in liquid state - if that's how it works.
- lern_too_spel 3y agoThe hydrogen is not in a liquid state.
- deleted 3y ago[deleted]
- starbase 3y agoHydrogen's critical temperature is cryogenic. There's no keeping it liquid at any pressure if it's warmer than -240C
- Alupis 3y agoCan you locate a source specifically for a vehicle like the Toyota Mirai or one of the newer big rig trucks using hydrogen? Everything I come across seems to imply they are using high pressure (10,000 PSI) but no talk about insulation or refrigerant. I could be missing it somewhere...
- 3y ago
- willmadden 3y agolol
- canadianfella 3y ago[dead]
- _hypx 3y agoIf you're assuming it is compressed, to say 700 bar, then it would have a higher volumetric density.
- seanmcdirmid 3y agoDon’t they heavily compress the hydrogen with special tanks and compressors? Making it really cold, for example, makes it easier to compress.
- pornel 3y agoBMW tried that. You weren't allowed to park the car in a garage, because it had to vent the hydrogen as it thawed. https://www.youtube.com/watch?v=AouW9_jyZck https://www.youtube.com/watch?v=AouW9_jyZck
- deleted 3y ago[deleted]