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DontWorryImADr t1_j1agg8b wrote

Reply to comment by ClapAlongChorus in How do fusion scientists expect to produce enough Tritium to sustain D-T fusion (see text)? by DanTheTerrible

So for a comparison, a single EV battery requires something on the order of 63 kg of lithium. Assuming this is even remotely true, we then have references from Youtubers like Real Engineering who estimate a commercial fusion plant would need about 600g of tritium per day.

Switching from mass to equivalent atom counts and then back to relate, 600g of tritium is just shy of 200 moles (3.016 g/mol). Multiplying this by the molar mass of lithium (6.941 g/mol) gets us ~1,382g. I couldn’t easily find an efficiency rate, so let’s assume we’re terrible at conversion and only manage 1% conversion rate: a plant would require about 138kg per day.

So while the lithium usage by a commercial power plant would be noticeable if they became super common.. it would amount to about two EV batteries per day, per plant. Considering we may need over 30 million EV batteries per year by 2030, this would be a very small impact.

Edit: month —> day Edit2: I was lame, got the molecular mass of tritium (T2) rather than atomic mass, and ran with the math. All fixed now.

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starmartyr t1_j1awu3m wrote

Would it be possible to extract the lithium from dead batteries?

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DontWorryImADr t1_j1b07jo wrote

It better be, considering the volume of waste if all those batteries need replacement every 10 years. That would be the order of 1.89 billion kg of lithium every battery replacement cycle based upon 2030 numbers. Considering some of the issues with lithium, that would be all sorts of bad.

I don’t know that commercial scale recycling of said batteries is truly ready, but hence why it’s a big area of examination and study when it comes to converting transportation away from fossil fuels.

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mrwolfisolveproblems t1_j1bph0g wrote

Battery end of life with EVs is the 1000 pound gorilla in the room that no one wants to acknowledge. All these states passing laws to ban sales of ICE vehicles have put zero thought into it that’s for sure. Not to mention the huge cost to consumers of said replacements. So insane to me that these problems are not close to being solved with EVs being jammed down everyone’s throat. I guess necessity is the mother of all invention, so hopefully mass EV adoption will drive solutions to these problems. End of sidebar.

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FRCP_12b6 t1_j1c8jic wrote

When an EV battery gets old it can still be reused as grid storage, even if the remaining capacity is low.

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mrwolfisolveproblems t1_j1ehkcm wrote

If an EV battery is so degraded it can provide a few hours of runtime in a car what meaningful use will it have to the grid? Has anyone actually tested this at reasonable scale beyond a simple demonstration? Who is going to pay for the infrastructure to connect all these old batteries to the grid? That grid storage argument is just thrown out there for PR. It would take decades to get off the ground and we’re going to have millions of dead battery packs in 10 years.

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FRCP_12b6 t1_j1emd2d wrote

The batteries need to be good power to weight density to be useful in a car. More weight means less range. A battery with 60% capacity is still useful on land, where weight doesn’t matter.

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mrwolfisolveproblems t1_j1gdayr wrote

So a 100kwh pack becomes 60kwh. A thousands of them together gives you 60MW for 1 hour. Peak load demand can swing 20-40,000 MW for 10+ hours at a time. That’s just peak demand, forget about base load, and that’s just in a regional area (say Texas for example) An extra 20,000 MW for 10 hours is 200,000,000 kWh. You would need 3.33 million old battery packs all tired together and synced to the grid. Not to mention every day they will lose capacity and eventually be useless even for grid storage.

TLDR: need to find a way to recycle them into new batteries like we do for lead acid batteries.

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Michaelmrose t1_j27glhf wrote

Recycling is complicated parties are working on it included the United States Advanced Battery Consortium—made up of General Motors, Ford, Stellantis, and the Department of Energy.

https://arstechnica.com/science/2022/04/lithium-costs-a-lot-of-money-so-why-arent-we-recycling-lithium-batteries/

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mrwolfisolveproblems t1_j28suc0 wrote

Thank you for posting that. Doesn’t seem like it’s too promising right now, but it’s being worked on and moving in the right direction it seems. Hopefully they make some leaps forward in the next 5-7 years.

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mrwolfisolveproblems t1_j28sxzf wrote

Thank you for posting that. Doesn’t seem like it’s too promising right now, but it’s being worked on and moving in the right direction it seems. Hopefully they make some leaps forward in the next 5-7 years.

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ukezi t1_j1b0zth wrote

Lithium 6 absorbs a neuron and gets split into a helium and a tritium, so you need two times as much as you need tritium.

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DontWorryImADr t1_j1dj3ra wrote

Why would you need twice as much if one lithium atom produces one tritium atom?

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ukezi t1_j1djugo wrote

Lithium-6 weights about double of tritium (Hydrogen-3). So for 1 kg tritium you need 2 kg lithium.

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DontWorryImADr t1_j1do3ej wrote

Yeah, that was silly. I looked up atomic masses, got the molecular mass for tritium and didn’t think twice about it in the math. Thanks for the catch!

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