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Can “second life” EV batteries work as grid-scale energy storage?

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Re: Can “second life” EV batteries work as grid-scale energy storage?

#171

Post by torginus »

nandomrumber wrote: post #115
torginus wrote: post #64

Earlier quoted context omitted.

Not sure if that's the case - however doing V2L requires the manufacturer to add an inverter to the car, and making that powerful probably adds extra cost most customers wouldn't pay. TI just looked it up and my Ioniq can only do about 2kW sustained - but since this charges the house battery, that's enough - idle load is just a couple hundred watts.

If the car charges the house battery, what charges the car?

You pointed out a significant limitation of my current setup - right now there are 2 plugs - one for discharging the car through a proprietary manufacturer's V2L adapter, and one for charging.

I'm planning to make a 'box' that can switch between the 2 functionalities on the same cable.

The whole setup is a bit clunky as it is right, now, but I'm kinda more surprised that it works at all, and how well the fundamentals work.

This whole thing was more of an experiment in 'no way you can do this' to actually doing it, but I think this is HUGE, and will transform the way people think about electric cars.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#173

Post by jillesvangurp »

bryanlarsen wrote: post #2

This is less useful than most people expected. Redwood has been struggling because the expected battery turnover is not occurring. EV batteries are lasting a long time, so they stay in the car are and not being recycled or reused in any quantity yet. If EV batteries last 20+ years in EV's, it'll be > 2040 before there are significant numbers of EV batteries available to recycle or reuse. https://www.geotab.com/blog/e…

That's part of it. Yet there is a growing gwh of EV batteries that gets retired on a yearly basis. Which is what Redwood has been tapping into. There is also a certain amount of cells that don't make it past the quality gates in the factory that get recycled via them.

Also people forget how quickly EVs have grown. The Tesla Model 3 came out in 2017; that's eight years ago. That was pretty much the first mass market EV that got produced by the hundreds of thousands per year. It had eight years of battery warranty. Most EVs you see on the road were produced after 2017 and typically come with similar warranty. The simple reality is that the vast majority of EV batteries ever produced is still under it's factory warranty and nowhere near its warranty life time. The amount of gwh of battery that becomes available for companies like Redwood is fairly predictable as it is tied to the production volume 8-15 years ago.

Redwood is basically tapping into the growing number of cars that get scrapped early because of accidents or other failures. That's a smallish percentage of overall vehicles produced but at the rate EVs started getting produced around eight years ago, it's starting to add up to a few gwh of battery per year. It's not a lot yet but it's not that unpredictable. And it's not nothing. If you manufacturer new batteries at 80$/kwh, producing 1 gwh new would cost about 80M$. So giving batteries a second life has quite a bit of economic value. The issue for Redwood is probably more that competition for these batteries is quite fierce. There is a lot of valuable stuff you can do with these things and lots of companies eagerly looking to pick up second hand EVs for their batteries.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#175

Post by eloisant »

dukeofdoom wrote: post #25

Seems like the market is going the hybrid route. It's kind of easy to see why, best of both worlds. Some BYD hybrids have crazy ranges like 1500 km on a tank of gas. The more practical car is winning. They put in a much small battery in these for fast charge, and the daily commute range. And you have gas, for longer trips. Maybe smaller batteries would be better for grid-scale storage too. If they're lighter and easi…

No, hybrid is just a temporary solution until the charging infrastructure becomes good enough. And depending where you live, it's already there.

Hybrid is the worse of both worlds in a way. You have a combustion engine to maintain, that is useless when using electricity. You have a heavy battery useless when using your combustion engine.

You don't get all the benefits of electric, and you don't get all the benefits of ICE.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#176

Post by metalman »

NO! first

only if industry and government grow some gonads and fully standardise the cells, and hardware for battery packs to allow for quick and easy dissasembly, testing, repair, and reuse, for off grid, and secondary mobile use, as industry will never trust used components for primary aplications, it is impossible to overstate how allergic industry is to this.....

second sodium is comming NOW!, and it is cheaper and safer.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#177

Post by jack_pp »

CursedSilicon wrote: post #159
MetaWhirledPeas wrote: post #132

Earlier quoted context omitted.

I would be more concerned if the source were anyone but Electrek~. Their vendetta against Tesla has forfeited all their credibility on Tesla news. "many of these vehicles are now out of warranty, as they sometimes exceed the maximum mileage" They have good numbers for the number of affected vehicles, but the best they can do for out-of-warranty stats is "many" and "sometimes". Convenient. ~To be fair this applies to…

>Dunking on Tesla is its own industry these days, it seems. Are you suggesting Tesla is criticized without good reason ?

Idk enough but I assume there are good reasons, however when a website is biased and finds even bad reasons to hate that's still a problem right?

Re: Can “second life” EV batteries work as grid-scale energy storage?

#178

Post by adwn »

torginus wrote: post #169
adwn wrote: post #143

Earlier quoted context omitted.

Today you can already get 51.2 V, 16 kWh batteries complete with balancer and BMS from a European supplier for 1200 € (1400 US$): https://www.nkon.nl/novat/nkon-ess-eco-s-51-2v-16-1kwh-thuis...

That looks quite a bit cheaper than the pricing I'm used to seeing, like less than half - not saying they're bad, but probably there's a DIY and risk factor involved compared to buying a more established brand like BYD or Huawei. I'm just pointing out this is way lower than typical pricing

Maybe, but I think the premium charged by the main manufacturer's is unjustifiably high. Those battery boxes are relatively dumb: besides the cells, they just need some voltage and temperature sensors for monitoring, some power electronics for balancing, a microprocessor, and an enclosure with connectors. Unlike a grid-tied inverter, this is a really simple system, and there's no way a 500–700% price premium over the cells is reasonable.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#179

Post by SirFredman »

adwn wrote: post #143
archi42 wrote: post #68

Earlier quoted context omitted.

Residential batteries are not that expensive anymore, at least not all of them. That's a misconception I also held until a few years ago ;-) My first 14.3 kWh pack cost about 2800$ DDP from China, delivered 03/2023. For that one I did calculate how long it took for amortization, which I projected at about 5 years. The second, identical pack was delivered 08/2024 and cost 2000$ DDP. Since we got an EV that's drawing a…

Today you can already get 51.2 V, 16 kWh batteries complete with balancer and BMS from a European supplier for 1200 € (1400 US$): https://www.nkon.nl/novat/nkon-ess-eco-s-51-2v-16-1kwh-thuis...

And the nice thing is, prices will only get lower. They also have a 32.15kWh system for €3500,- which is insane.

Re: Can “second life” EV batteries work as grid-scale energy storage?

#180

Post by sandy234590 »

kragen wrote: post #152
kragen wrote: post #130

Earlier quoted context omitted.

I haven't seen pfdietz's proposed system design, but a so-called "sand battery," consisting of a box of sand with a heating element running through it, should work fine. You can PWM the heating element with a power MOSFET to keep it from overheating; you can measure its temperature with its own resistance, but also want additional thermocouple probes for the sand and to measure the surface of the box. A fan can blow…

A thing I forgot to calculate: with 75m of wire dissipating 533 watts per meter, how thick should the wire be? Suppose we divide it into three 25m circuits so that we still have most of our heat if a wire burns out, and suppose we're using 48Vdc. So E ²/ R = 13.3kW, R = E ²/13.3kW = 0.173Ω, and each of those elements is carrying an astonishing 277 amps. So we want 7 milliohms per meter. It turns out that that's about…

Maybe stainless steel for the heating elements and busbars?

Cheaper than nichrome and copper. I feel like mild steel would not last long in practice.

Copper plated MIG welding wire might be good enough?

Probably want to think about thermal expansion also, especially configured as "walls", and with skins considerably colder than cores.

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