Low batteries on your Tesla? Swap ‘em out | Hacker News Reader

Low batteries on your Tesla? Swap ‘em out

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44 pointswaster51 comments

I wonder if this is motivated by ZEV credits; I think rapid refill zero emission vehicles qualify for a lot more credits--possibly even if no owners take advantage of the feature. So just having a few rapid recharge stations that nobody uses could be a huge financial windfall for Tesla, allowing them more profit on each car sold--again, even if owners never once swap a battery.

Source? My search was fruitless.

www.greencarcongress.com/2013/05/zev-20130502.html

Looks liken California is thinking of closing this loophole; nothing a little lobbying can't fix.

If we're going to be swapping things at charging stations, why not use a technology like this:

http://www.phinergy.com/

Takes a refill of plain water every ~200 miles and a swapping of aluminum at larger intervals. Aluminum is common as is the recycling of it. It's also a lot easier to handle than battery packs I would imagine -- lighter, safer, etc.

Not sure about the range but early press suggests it to be at least 1k miles between changes. I put around 4k miles on my car a year (much lower than average, I know). I take my car in at least twice a year for service so it would get half of them "for free".

Even at 12k miles per year that's only once a month. If it could be done in 15 minutes (a number I just made up) that's not much of a PITA.

I wonder what the cost would be vs gasoline vs the cost of buying a car packed with LIBs.

> why not use a technology like this

Because it is highly inefficient, requires a large infrastructure, is susceptible to air pollution, and has low power density?

Versus battery electrics have infrastructure at every home, are upwards of 93% efficient, don't use air, and have plenty of power.

> and has low power density

Wikipedia:

"They have one of the highest energy densities of all batteries ... an electric vehicle with aluminium batteries has the potential for up to eight times the range of a lithium-ion battery with a significantly lower total weight."

> Because it is highly inefficient

I just read in the 20 - 30% range. One, that's a lot better than a gas burner. Two, your magical 93% doesn't account for the efficiency of the source of the electricity. Over 40% of the electricity produced in the US is from coal. The average efficiency of a coal plant is around 30%.

Coal plants are also the #1 source of greenhouse gasses in the US.

Tesla's filed eight patents for metal-air batteries. Phinergy said they'll have a 1000-mile EV by 2017. Can't imagine a 30k Tesla with this technology.

http://tech.slashdot.org/story/13/04/23/199248/will-future-t...

But all I can really think about are electric supersonic VTOL jets. Which might crash if you fly too high...

> Tesla's filed eight patents for metal-air batteries.

> Can't imagine a 30k Tesla with this technology.

Sounds like Musk can imagine it. Don't know about anybody else but I'll side with Musk vs anonymous HN poster #5674.

> But all I can really think about are electric supersonic VTOL jets. Which might crash if you fly too high...

All jets crash if they fly too high. (Well, it's not necessary that they crash but they have a well defined operational ceiling.)

Perhaps I am misreading your comment but "can't imagine" is a figure of speech. I meant I was excited for the possibility.

And the last statement was just referencing my ignorance about metal-air batteries working in oxygen-limited environments.

So the preeminent difficulty with aluminum-air is the cost of aluminum. Going off phinergy's number (8 kWh/kg), and assuming Tesla-parity range of 260 miles for an 85 kWh fill-up, you need 10.5 kg Al per fill-up, which costs $1.80/kg on the London Metal Exchange as of today, costing about $20/fill-up, or -eep- eight cents a mile, before considering tax, transit, manufacturing etc. For comparison my 2009 Toyota Prius (yes, I -am- that lame) costs nine cents a mile for fuel (350 miles, nine gallons, $3.50/gal). So aluminum-air largely negates the cost advantage of an electric battery, unless phinergy can come up with a superior way of making aluminum, which is already one of the most optimized processes in modern industry: the cryolite process has absorbed millions of hours of human attention.

If the power-density problems can be solved, zinc-air or similar may still be a good idea. Zinc is, unfortunately, quite heavy.

Incidentally, I have put over 15k miles on my car this year alone. Some people drive a lot.

That doesn't account for the recycling of the aluminum which by itself is quite efficient.

I just pulled up a number of around $1/kg for scrap aluminum. That's 55% of your cost. I'm sure that's wildly optimistic but that drops your fill up to under $10. That's in the ballpark of the electricity costs for the Tesla.

I'm afraid it's not that easy. The aluminum used in the battery is oxidized and must renter the cryolite process to be electrolysed; it's no ordinary recycling. There isn't enough scrap aluminum in the world to power 1000 cars, let alone 10000000!

I don't think battery swapping is a great idea. The problem is that the battery is such a huge part of the car's cost. I can only guess, but I would estimate $15,000-20,000. Getting someone else's poorly treated battery could drastically effect the resale value of the car. The other company in the article tried to mitigate this problem by actually owning the batteries, but that isn't Tesla's model.

If I understand the idea correctly, you'd be swapping out your (depleted from a road trip) battery for someone else's (or Tesla's, if they shifted to a model where they provide some of the batteries at the swap-out stations), and then next time you wanted to swap again, you'd get another one. Doesn't seem to me to be a factor for resale. Seems like they're pitching it instead as a way to increase the range of a car while on the road, though I'm willing to say I've misunderstood based on my (twice) read of the article.

If they are planning to release further detail Thursday, though, that'll presumably clarify.

If they take my (say) brand-new Southern California battery and replace it with someone's two-year-old Salt Belt battery, that's going to decrease the value of my car.

>that's going to decrease the value of my car.

Forgive my ignorance, but how? Cheap battery swapping would mean that all batteries are essentially fungible. What stops the new owner from just swapping batteries again? What stops you?

You're also forgetting that Tesla has a very generous battery warranty. Unless you don't think they'll honor it. http://money.cnn.com/2013/04/26/autos/tesla-service-gaurante...

Cheap battery swapping would mean that all batteries are essentially fungible

Which will be interesting. I wonder if at that point the "tragedy of the commons" would start to set in. "Oh, it's ok if I run this battery totally flat all the time, it will shorten the battery's lifespan a lot, but I can just swap it for another!"

Why would you leave your car intentionally empty? Why inconvenience yourself like that?

There might be people who can't plug in, but that'll happen regardless of swapping. You might make the argument that swapping could convince more people in that situation to buy the car, but that's hardly a downside for Tesla Motors.

>it will shorten the battery's lifespan a lot

It doesn't do that if you set your depth-of-discharge correctly. Lithium cells are more sensitive to temperature than charge cycles anyway.

You could use the battery controller to implement restrictions. (E.g. allow it to be run flat only once per owner per month) or perhaps simply log the stresses they put on the unit and charge accordingly.

Deleted comment

Well, presumably the swapping company would make sure the batteries are well maintained. If someone swaps out a damaged battery, the process should detect that and charge them extra, and not put the bad battery in the queue for swapping.

That opens up a whole can of worms. How do you quantify the damage? If my battery is degraded 10% do I pay $15,000 * .1 = $1,500 just to get back on the highway? Like I said, this is easy if the customers don't own the batteries, but right now they do, and those batteries are very expensive.

I think perfecting the whole supercharging system makes more sense.

If I were Tesla, I'd do both.

Which would be nice for owners. Recharge your battery until it shows signs of age. Then swap it out repeatedly until you get a newish one, then go back to recharging only.

Combine it with a better recycling process: lithium based batteries are insanely energy intensive to produce to begin with so they are a great candidate. Then, chose the most efficient point in the life cycle to recycle the battery to recover the most cost. Since you're extremely unlikely to use a swap station for the first time after having used the car a long time, the risk to Tesla can be minimized.

Factor in the price of recycling with a cynical view of the average user and everyone gets a price decrease on the batteries without the sticker shock of seeing the battery cost all at once. Really you'd sell your Tesla's with an already recycled battery and a couple of years of swapping thrown in. You can price it just like you price car insurance, based on amount of miles driven a year.

Anything that puts more control of the most unproven tech into the hands of Tesla, the faster their batteries will improve. But maybe this is all just too expensive to implement without millions of cars on the road.

Self-service battery warranty. It's a win-win.

Agreed. Though I imagine it'd be a subscription model, where if you're in the program, you won't have to worry about battery capacity/depreciation at all.

The capacity of batteries in rotation would be maintained at a certain level, and the old batteries recycled or used as storage for the superchargers. I think it could potentially cost less than the monthly cost of gasoline for most people.

>used as storage for the superchargers

Superchargers don't use batteries. SolarCity does, though.

http://www.solarcity.com/residential/energy-storage.aspx

Oh but they do/will.

Musk said that the ones with solar panels can go completely off the grid and continue to work in a zombie apocalypse. The only way that is accomplished is through energy storage.

http://www.cnbc.com/id/100777849

I imagine that the proposed swapping stations would be able to automatically detect a damaged battery. I'm not an expert, but monitoring the voltage curve during a test charge/discharge cycle would probably get you pretty close. Remove them from the system and, assuming a subscription program, charge the offending driver for the cost of the battery or refurbishment.

Plus the obvious problem that it presumes all automotive batteries will be electrically and mechanically identical... or at most there could be a small number of variants that they keep in stock. If all the world's a Model S it could work, but if electric cars become the future it seems likely there will be variation for different body styles, price ranges, etc.

Battery swapping might have a niche future for urban fleet applications (taxis, police cars, ...) where battery ownership and vehicle diversity aren't issues. Maybe Tesla is trying to make moves there?

If all the world's a Model S it could work, but if electric cars become the future it seems likely there will be variation for different body styles, price ranges, etc.

Funny, this isn't a problem in consumer electronics, where thousands of different devices from flashlights to ghetto blasters use one of a very small number of battery sizes.

Don't think of it as swapping one monolithic battery... think of a Ferrari that runs on two 'AAA' cells, a Buick that runs on two 'AA's, a FedEx truck that runs on four 'C's, and an eighteen-wheeler that takes sixteen 'D' cells. Service stations would only need to stock a few discrete sizes.

It seems like an electric car could be made with two sets of batteries: one swappable and one not. Use the swappable one more or less where the gas tank is and use custom sized batteries elsewhere.

You'd have to swap batteries more often on a long trip but I could see the swapping easily taking the same amount of time as filling a gas tank.

The problem is that the battery is such a huge part of the car's cost.

It would make more sense to lease the battery.

I don't think battery swapping is a great idea.

On the contrary, it's the only way EVs can possibly work for the masses. The drawbacks of swappable batteries are substantial and worrisome, but the potential benefits are staggering.

Why can't the masses just plug them in at night like current Tesla owners?

Imagine you are told that you have to spend the night in the middle of nowhere on your weekend trip mere 600 kilometers from home. Just to charge the battery.

Tesla supercharger stations charge the batteries in an hour.

Those are a gimmick. Completely non-scalable. Imagine the lines at gas stations if it took an hour to fill up.

The thing I keep coming back to is this: as we transition to EVs, we have a once-in-a-century chance to do it right. Look how badly we screwed ourselves during most of the twentieth century when gasoline-powered cars started to become popular. Lead in gasoline. No emissions or crash-safety regulations. Transportation planning driven by politics rather than logic.

We need to be a little smarter this time around. That means not allowing the market to evolve in a manner that leads to 20 different manufacturers selling us vehicles with hardwired proprietary batteries that we charge by plugging them into the same outlets that charge our electric toothbrushes. It's frustrating that nobody seems to understand how dumb that is.

That would require a seventy foot extension cord hanging out my window.

7-8 hundred feet for the people on the other side of my building.

and that's for 120v

Our power grid isn't what it needs to be to make that a widespread, scalable strategy, IMHO.

You do realize that battery swapping stations would also have to charge the batteries from the same grid?

You do realize that battery swapping stations would also have to charge the batteries from the same grid?

Sure, but not at the household 120V/240V "leaf nodes," where much of the power is wasted before it ever reaches my car.

Ideally, EV batteries could be swapped at any gas station. Just as gas stations don't need their own oil wells, the batteries they lease could be charged and maintained at centralized plants with minimum electrical losses and optimized load scheduling, and trucked to the service stations. At some point, probably very soon, the energy-management advantages will exceed the energy used by the trucks.

This scheme will ultimately require mandatory standardization of battery form factors, much like fuel standards are already legislated. Fortunately, with modern power conversion technology, only the physical sizes of the batteries will need to be specified. Manufacturers will be able to compete with each other on chemistry, pricing, weight, and other factors.

In engineering terms, migrating to EVs any other way is insanely goddamned stupid, and that's why I just bought a new fossil-fueled car. I keep my cars a long time, though, so I'm optimistic that by the time I'm ready for my next one, it'll be a Tesla. That will happen only if I can spend less time refueling it than I do now, and not more. And that, in turn, can happen only with swappable batteries.

Though I'll believe it when I see it in (user) action, this would make a huge difference, IMHO, in the usability of the car. It would make it truly feasible to drive to Tahoe from the Bay Area, for example. That's something I'd pay for.

It's been done according to http://www.teslamotors.com/forum/forums/cold-weather-dont-ig...

There is a supercharger at Folsom, so it's totally feasible.

I'm just waiting for a Model X AWD :)

::checks GMaps:: TIL a 4 hour 20 minute trip is unfeasible, but a 3 hour 50 minute one is fine. ;)

Until you're traveling at freeway speeds, in cold weather.

http://www.nytimes.com/2013/02/10/automobiles/stalled-on-the...

So I'm not sure even 3 hr 50 m would do it?

SF to tahoe (on I-80) never takes me 4 hours ;)

High overhead, but if it can be done quickly and for a not exorbitant price, probably a winning idea. I imagine they'd charge people a yearly service to be in such a program.

wasn't this the premise of the Israeli startup, Better Place? which just went bankrupt?

The article talks about that.

A Better Place's problems were getting car manufacturers onboard, and building infrastructure. Tesla ARE a care manufacturer, and they're already building infrastructure (their charging stations)

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