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Nickel Hydrogen Batteries by NASA

spectrum.ieee.org

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Re: Nickel Hydrogen Batteries by NASA

#41

Post by ilyt »

jillesvangurp wrote: post #31
dabeeeenster wrote: post #9

Earlier quoted context omitted.

EVs do 100% need to get lighter. They are still quite a bit heavier than their ICE equivalents and tyre wear is (IMO) underappreciated as a toxin/pollutant.

There are quite a few lighter EVs. Including some classic car conversions that actually manage to be faster and lighter than their originals. Those cute little EVs that are mass produced in China are far lighter than the super sized trucks people in the US drive. And of course any muscle car burns out its tires, brakes, and has terrible fuel economy.

Most people buy neither small EVs (they have family) nor musclecars (they, again, have family)

Re: Nickel Hydrogen Batteries by NASA

#42

Post by CyberDildonics »

It's strange they didn't compare these batteries to lithium titanate, which is the other chemistry that can do 30,000 cycles and is something anyone can buy right now. They have extremely high charging C rates and sit somewhere between normal batteries and full capacitors in what they can do. They end up being about 50% more than LiFePo batteries in cost.

Re: Nickel Hydrogen Batteries by NASA

#44

Post by goodcanadian »

jakobnissen wrote: post #14
gameoverhumans wrote: post #8

Earlier quoted context omitted.

As I understand it, electric cars are actually surprisingly polluting, which is a consequence of their battery weight and particulates from tires: https://dynomight.net/tires/

The blog in your link seems to conclude that electric cars pollute less than petrol cars overall. Still, if the blog is true, it's still surprising that such a large amount of air pollution comes from tyres and brakes. A little Googling does support this claim.

Tyres, absolutely. Equivalent size EVs are heavier (due to the batteries) which creates more tyre wear. My brakes, however, wear far less than on a petrol car due to regenerative braking.

Re: Nickel Hydrogen Batteries by NASA

#45

Post by CyberDildonics »

AtlasBarfed wrote: post #4
scott_h wrote: post #2

[dead]

CATL's sodium ion batteries are slated to soon (1-2 years, mostly just mundane factory construction and logistics) to hit $40/kwhr. No nickel / cobalt / etc. I think LFP is basically already under that as well (I think they are in the 60-70/kwhr range). For grid storage, that is probably the only metric that matters: cost per kwhr of storage (and sufficient cycle endurance).

How can LFP be both under $40/kwhr and in the 60-70/kwhr range?

Re: Nickel Hydrogen Batteries by NASA

#46

Post by goodcanadian »

jojobas wrote: post #17
jakobnissen wrote: post #14

Earlier quoted context omitted.

The blog in your link seems to conclude that electric cars pollute less than petrol cars overall. Still, if the blog is true, it's still surprising that such a large amount of air pollution comes from tyres and brakes. A little Googling does support this claim.

It could have something to do with the fact that in order to regen-brake a 1800kg car at your typical 0.5g at 100 km/h you need some 270kW of motor/generator power. This is the main reason your Teslas and Polestars have these otherwise outlandish engines, and if you already have it, why not accelerate at traction limit, creating all these aerosols and what not.

It is extremely atypical to be braking at 0.5g. That is an emergency braking situation, in which case, it is perfectly reasonable to be engaging the mechanical braking.

Re: Nickel Hydrogen Batteries by NASA

#48

Post by littlestymaar »

ilyt wrote: post #41
jillesvangurp wrote: post #31

Earlier quoted context omitted.

There are quite a few lighter EVs. Including some classic car conversions that actually manage to be faster and lighter than their originals. Those cute little EVs that are mass produced in China are far lighter than the super sized trucks people in the US drive. And of course any muscle car burns out its tires, brakes, and has terrible fuel economy.

Most people buy neither small EVs (they have family) nor musclecars (they, again, have family)

You definitely don't need a 3t truck to carry your family, especially when you know how small modern families are… The average household size in the US is 2.53. And 63% of households are only made of one or two person (that is, the majority actually doesn't “have a family”), which fits in 482 kg Citroën Ami.

Also the most common car in Europe (Dacia Sandero), which is a 5-seater only weights 1 036kg. Gigantic American cars are a cultural phenomenon (which is mostly ad-driven by the way), it doesn't relate to an actual need.

Re: Nickel Hydrogen Batteries by NASA

#49

Post by jojobas »

goodcanadian wrote: post #46
jojobas wrote: post #17

Earlier quoted context omitted.

It could have something to do with the fact that in order to regen-brake a 1800kg car at your typical 0.5g at 100 km/h you need some 270kW of motor/generator power. This is the main reason your Teslas and Polestars have these otherwise outlandish engines, and if you already have it, why not accelerate at traction limit, creating all these aerosols and what not.

It is extremely atypical to be braking at 0.5g. That is an emergency braking situation, in which case, it is perfectly reasonable to be engaging the mechanical braking.

Modern cars emergency brake at 0.87-1.08g. Maybe 0.5g is not your everyday braking, but not something you'd remember in a few weeks. https://www.sae.org/publications/technical-papers/content/20...

Re: Nickel Hydrogen Batteries by NASA

#50

Post by pjc50 »

mcdonje wrote: post #47

Since it's relatively low pressure (5% of a hydrogen fuel cell), couldn't they have larger batteries for grids? The current size would be great for homes.

That looks suspiciously similar to a standard gas tank size.

Generally you make a battery by combining cells - they have a 1-1.5V terminal voltage. The image lower down shows a rack of them in a warehouse. I suspect you'd stack them up to a few hundred volts and plug them into an inverter.

I wonder if they require the same balancing as more delicate chemistries.

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