cross-posted from: https://lemmy.ml/post/17926125

-10 points

There needs to be a metric for how many gallons of water/kg the fire department will need to spray to extinguish the car.

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10 points
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The number is zero gallons, or sometimes very little.

Trying to put out the self-oxidizing reaction of a lithium battery that way is a waste of time and water. Fire fighting teams that try to put it out like that will see the flames go down, then they let off, and then it starts right up again. In the end, the car burns through the entire battery pack one way or another. You’re just delaying the inevitable, and it takes most of the day and swimming pools of water to get done.

Fire crews need new training and equipment. If possible, the car needs to be towed to a safer location. Then you let it burn. There are fire proof blankets that can cover the car to prevent spreading the fire elsewhere. Takes about an hour. Sometimes, a little water helps prevent spreading to other things, but it’s minimal.

Edit: https://youtu.be/mNYwpTrYYBM

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3 points

What are these fire proof blankets made of??

Like seriously I don’t understand how a blanket could resist such intense fire for hours

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4 points

Some combination of pyroxene and silicium is typical. Fire containment blankets aren’t new, but this is a new form factor in a package convenient for one or two fire fighters to cover a car safely.

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43 points

Well, it’s a Chinese lab claiming to have it. So, I guess I’ll just wait for the proof.

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22 points

Yup. I’d wait regardless of source, but it’s extra sus coming from a Chinese lab since they like to… stretch the truth sometimes.

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12 points

China is the center of lithium ion battery tech nowadays. I’ve recently seen that they managed to bring down battery prices by 50% in the last two years and their EVs are cheaper than combustion based alternatives for 2/3 of models being sold.

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14 points

Economy of scale is different from groundbreaking novel developments in the field.

China is also the runaway leader in false discoveries and purposeful fraud in academia.

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3 points
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Agreed on all points but I have trouble believing that with this economy of scale there would be no money being pumped into R&D and in time some results of that.

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4 points

But also the center of bullshit stories & studies.

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22 points

Current tech is 200 to 250 so a substantial reduction in battery weight, 50% or 60%

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16 points
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Huge leap forward if the process is in the same ballpark expense wise. Being able to reduce a cars battery by 50% would reduce the prices by at least 5k, and likely have longer range because of the reduced weight.

Edit : still very experimental. Battery only retains that energy density for 300 charges. This is an improvement from an earlier 50 cycles, but not really viable either.

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15 points
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I used to have some old copy pasta for this on Reddit but I’ll be damn if I’m logging in to retrieve it.

So I’ll paraphrase:

Has the battery been made or is it a concept? Has the battery been made to the scale that the claim argues it can hit? What is the price? How many charge cycles? What’s the temperature range it can operate within? Can the battery fit into the existing production processes or will it require new tooling to productionize? Does the battery require any novel materials that aren’t available at scale yet or at the price that’s been assumed? Does the production of the battery have any bi-products that haven’t been handled industrially before? Will the battery require new safety approvals? Will the production require new safety training? What’s the size and the weight of the battery? What’s the charge and discharge rate? How does the temperate of the battery get affected by charging and discharging? Is the battery as safe under puncture and deformation as existing batteries? Can the battery be recycled as easily as existing batteries?

Etc etc

“China develops new battery” needs an answer to all these questions before anything meaningful has been developed. Until then it’s just a theory in a lab. For every 1000 things that work in a lab, one escapes and becomes a product you can buy in a store.

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8 points

As someone that worked in a battery lab for a short period of time I agree. These are exactly the types of questions that need to be asked for any battery related technology article (not just China, other institutions around the world do this as well)

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25 points

Just for comparison: the energy density of gasoline and diesel is around 10,000 Wh/kg.

Never knew about this metric before.

I’m looking forward to the instant benefits for e-bikes!

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26 points

The thing is when gasoline is used to power a car about 80% of the energy is loss to heat and only about 20% is used to actually move the car on average. It’s worse when you are doing acceleration and better when cruising at a steady speed on a level surface.

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15 points

Yeah, so you have to divide it by a factor of 5. Which still makes gasoline roughly 5 times as energy dense than this prototype battery, instead of 25 times.

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8 points

Another problem is the increased complexity of fossil fuel vehicles, specifically in stuff like the engine, gears, pollution filters, etc. A fossil fuel vehicle is just intrinsically more complicated. Which doesn’t directly relate to the density, but it gives electric vehicles an advantage.

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13 points

In general efficiency, modern cars are a lot closer to 40% than 20. E.g. a Prius engine is at 38,5%.

It was interesting to see F1 engines go past the 50% mark, a few years back.

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10 points

Not sure how much it’d improve ebikes. Maybe if you want to take a bike trip longer than 100 miles.

If anything, sodium batteries are more exciting for ebikes. They’re more than enough for getting around town, and they’re cheap.

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