Rapidly falling costs of battery packs for electric vehicles | Hacker News Reader

Rapidly falling costs of battery packs for electric vehicles

nature.com

65 pointscrawshaw35 comments

Does anyone know how long something like the new Tesla powerwall lasts? What happens after the useful life of the hardware, can they be recycled/fixed?

The warranty lasts 10 years. It is basically guaranteed to work for ten years. This is probably analogous to the 60k mile warranty that comes with a Prius. Nobody is junking their Prius after 60 thousand miles.

Look at the press kit for more information.

http://www.teslamotors.com/presskit/teslaenergy?via=newslett...

I'm not sure about the specific chemistry used in Teslas thing, but consumer grade Lithium Polymer cells are usually quoted as maintaining 80% of initial capacity after 1000 charge/discharge cycles (when using proper recharging gear - sub $10 Chinese toys often ignore charge requirements altogether and trash or set fire to lipos within a few dozen cycles). Which fit's quite well with observations of phone batteries becoming problematic after ~3 years of daily charging.

Keep in mind that phone batteries, and laptop batteries, are generally charged to the top and then often completely exhausted. This is a worst case state-of-charge scenario for battery life, and doesn't happen in car batteries etc. For example, the Chevy Volt doesn't permit its battery to be charged over 80% or discharged less than 30%. GM expects its battery to drop only 10% after 5000 cycles.

Teslas do similar on the top-end. They don't normally charge past 80%. You can override this behavior in preparation for a long trip to ensure you have extra range available, but it reverts back to the default setting automatically after a few days.

> They don't normally charge past 80%.

I thought for Tesla it's 92% for a standard charge. The Volt is extremely conservative in this regard (Chevy was first out the gate).

As Lutz says in his book "Car guys vs. bean counters", that was done to make the Leaf battery last longer. The car industry knows that 80% of trips are under 40 miles, so most of the time, that's enough range. Longer, and they cut in the gasoline engine, so there's no reason to stress the battery life.

??? This was an entirely confused comment. (1) we are talking about SOC, not capacity, and (2) why are you talking about the Leaf?

Personally, I'm very excited about electric vehicles. There are five in my family, so we have a big vehicle. So, to move something the size of a Suburban is a necessity. The Tesla Model X looks like a possibility.

Most full-size sedans can comfortably transport five adults. Get a station wagon, and you've got plenty of cargo space too.

You don't really need a massive SUV.

Most families of 5 have a number of years where they are not seating "five adults". I drive a sedan and have two kids under 5 years old, a 5th passenger is basically out of the question. If you had 3 kids in car seats, a vehicle with a third row is seating is your only option.

I have 3 across the back seat, all in child seats. It's more possible than most people realise.

Oversized child seats are a major cause of people driving cars bigger than they need to. I'm not sure how this has happened, but you can end up needing more space to fit a child than an adult would require. I suspect it's the proliferation of region- specific child restraint requirements, which has meant manufacturers have washed their hands of the problem. The car seat manufacturers have worked out that the more a seat looks like an oversized sofa for their precious cargo, the more sales they make. I doubt that an inch extra of foam padding makes any difference in a large impact, but it feeds into anxiety of new parents.

I would basically agree except that it doesn't change the availability of smaller car seats, the small sofa chair car sest is practically a universal design, and the highest rated brands (which is largely synonymous with "convenient and well designed") are some of the worst offenders of space usage. I just transitioned one kid to a booster seat and it actually takes up an normal adult width finally.

Battery cost is only part of the problem, the bigger problem is ability to charge where potential customers live and charging times. Unlike a conventionally fueled car, or EREV, there is no oops with a five minute fix. You forget to charge and you have to wait it out.

I think a better application is instead of focusing on individual car buyers is to go for large government users of vehicles, namely the every day school bus. A neighboring county logs nearly sixty five thousand miles a day while school is in session. With nearly nine hundred routes that leaves an average near eighty miles. Considering the wasted space in the buses structure and replacement of the engine/drivetrain it certainly looks like a good option.

Regardless of price decreases its the recharge rate that needs a lot of focus.

I disagree, as the charge rate of a pack increases with its capacity. That is to say, there is a fixed time for a 0-100% charge, but as capacities increase, the time for a X mile charge decreases.

>the bigger problem is ability to charge where potential customers live

Is this really a problem? Every EV I've ever seen offers a home charger that can be installed in your garage. I drive very few miles each week, and find going out of my way to stop at a gas station much more inconvenient than plugging in each night would be.

Out of 6 or 7 friends who live within walking distance of me, I'm the only one with a garage - one of them has a side entrance/carport, everyone else parks on the street. (And depending on exactly what "install" means, putting one in my rental garage might not be possible.) Further afield, I've got quite a few friends who live in high-density residential buildings, where their "garage" is a space in the big lot underneath the building, and has no facility for power (and certailnly not individually metered power).

Plugin electrics are good for people who own houses - not yet so good for everybody else.

New apartments (and single family homes) where I live are required to provide hookups in their garages, and as a dweller in an older apartment block, I get along fine charging overnight at a nearby parking garage. But really, it's not about you and me or your friends, it's about the % of the market that can be served by EVs. And that's plenty big for the size of today's EV industry.

We have the same discussion every time EVs come up on HN.

Yep - sure.

Though as it turns out, I _am_ part of the market that can be served by an EV - I ride a battery assist bicycle to word a couple of days a week, and I'm collecting parts to build my own homebrew electric motorcycle, I've got a running bike in the garage which I'm planning to gut of it's IC parts, and a line on a possible 2kWhr worth of Tesla battery pack cells.

I love my 16 year old dinosaur burning Ducati, and intend to keep polluting the environment with it for decades more, but much more selectively than wasting it on commuting.

To be fair, it's not like you can completely ignore the remaining range in your dead-dinosaur fuelled vehicle either. If you run out of gas on a freeway or backroad in the middle of nowhere, you're still gonna get annoyed at your "oops".

I'm probably a bit more aware of this than many - I ride a motorcycle with only 200 or so km (maybe 130mile) range, and take it _lot_ of places where keeping a good running tally of where the next fuel options are, and how I'm gonna get home if the next place happens to be shut.

I suspect that in under 5 years, there'll be roadside assist vehicles with big 3 phase generators on board that are capable of Tesla Supercharger kind of rates of charge.

AAA did it in 2011: http://newsroom.aaa.com/2011/07/ev-charging-statio/

"Level 3 charging" here means DC fast charging: 125 amps at 500 volts (depending on the vehicle)

/me pulls a technicality and claims "minus 4 years" is "less than 5 years" - thus being proved correct.

If you run out of gas on a freeway or backroad in the middle of nowhere, you're still gonna get annoyed at your "oops".

That's what the spare tank in the boot is for.

For EVs, I suppose you could carry an extra small battery pack, to be plugged in when you need an extra charge not unlike those for mobiles, but it would have to be kept charged too.

> the bigger problem is ability to charge where potential customers live and charging times. Unlike a conventionally fueled car, or EREV, there is no oops with a five minute fix. You forget to charge and you have to wait it out.

How about swapping in a pre-charged battery at the charging station, instead of charging the one you brought with you? Some EV idea posted recently on Hacker News used this plan. If it's too hard to swap the large battery for an electric car, at least have a small secondary battery that can be swapped and can get you home.

This has been tried a few times, and Elon has even demonstrated it on the Model S (it's faster than filling up a large-tanked luxury car). The super charger is close enough to instantaneous that I think we'll get to fast-enough recharge times and large enough capacities before we get to a nationwide battery-swapping network.

As someone who made the ev switch just over a year ago, this is not as much of an issue as I'd thought it would be and that's with a leaf (and me commuting over 50 miles a day one way).

I was actually considering the leaf for a fifty mile commute. Do you have to charge during the day or can you do the whole 100 miles with no worries? What about hot/cold weather, traffic?

Absolutely have to charge during the day. The charge varies by as much as 15 miles when it gets really cold. Summer doesn't affect it as much, but it can still vary by as much as 10. The mileage estimation in the dash is never right, so this is based on personal experience and what the car said was left when I plugged it in.

Ah thanks. So in my case I wouldn't be able to charge it during the day so I ruled it out. I guess I need to wait for something with 150 mile range?

Supercharger says Hi.

300A at 400VDC, usually only a ~15-20 minute charge to get enough juice to make it to the next one.

When I'm heading home the last one on my trip ~80 miles away is usually 10 minutes from offramp to onramp.

non paywall version?

http://rdcu.be/cIqD

Doesn't work on mobile.

Not the paper itself, but blog post from the authors, and (I think) has the main chart: http://www.rtcc.org/2015/03/23/falling-battery-prices-boost-...

http://libgen.org/scimag/index.php?s=Rapidly+falling+costs+o... (click on "10.1038/nclimate2564"; I had to rename the file from "get.php" to .pdf after downloading)

Reply on news.ycombinator.com