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Comment by rattray | Hacker News Reader

So... these are too heavy for use in cars etc, too low-voltage to displace Li-ion in ¿many situations?, but would last a long time?

What applications, if any, would this kind of battery be useful for then?

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Anywhere you need a small but longer lasting battery and don't care about mass. The primary issue with a larger mass is accelerating and decelerating it. However with the larger capacity, it would be less efficient but perhaps could still lead to longer range in the car if the extra energy stored overcomes the added cost of moving it around. Probably not a good thing but could be useful then in something like an electric race car or something.

Submersibles (which may not care about weight due to ballast anyhow), Batteries for Solar Storage (price dependent likely bad at first), Pacemakers, Hearing aids, once it's invented if robotics outpace man engineered human biology, maybe smart blood.

Perhaps also Nanobots, Active 3d Glasses, Cell phones, Laptops, Tablets, Smart Watches that go for smaller space vs weight.

Outside of that perhaps home appliances like a portable bread machine, or a hand-held wireless electric apple peeler, very small things like a rock that has a hidden microphone / camera in it for spycraft, perhaps a heated travel mug to keep your cider warm, or an electric bowl for keeping great-gravy from coagulating on the dining room table, maybe a warm pie plate because who doesn't like warm cherry pie? Perhaps some sort of autonomous mud tunneling microbots, rather have a large boring machine just let these small guys go and be patient and in a decade or two you'll have your tunnel, electric candles in churches could cut down on unnecessary wax use, and helmet lamps used for stuff like lead mining could also find a use (added neck strain not withstanding). Not sure if the added weight would be too much for a target-practice duck that swam around in a lake or not, but if not, that might be the right answer.

I think that in many cases, smaller but heavier with more power is a good trade-off. Think cell phones, cameras, bike lights, camping lights, laptops, etc. while lightweight is a feature for all of these, they're also useless without a charge, so IMO the battery life and size together are more important than weight as long as it's still reasonable. Glass isn't light at all, yet they use that a ton in phones. The iPhone 6S Plus is really heavy and I haven't heard anyone complain about it. The efforts around consumer electronics I've seen in the past 20 years have mainly been about reducing size, with reducing weight as a nice typical side-effect.

This would be really great if it ever hits production, but given past battery progress vs what's actually available, I'm not holding my breath.

> The iPhone 6S Plus is really heavy and I haven't heard anyone complain about it

A significant amount of that weight is the battery, so making the battery 2.5x heavier would make the phone substantially heavier, even with the same overall charge. You'd be hard pressed to sell someone on 'This new phone we made is great, you get the same battery life as before but it weighs 40% more!'

I suppose the question is, in which cases would people be willing to accept a lower charge capacity if their phone could charge to full in, say, minutes rather than hours? I feel as though those USB battery packs that are everywhere these days would be a great candidate; plug it into the wall for a few minutes and you're fully charged, and you can charge anything else from there.

>You'd be hard pressed to sell someone on 'This new phone we made is great, you get the same battery life as before but it weighs 40% more!'

It's actually super easy, you just say things like "solid construction", "substantial", and "build quality".

> It's actually super easy, you just say things like "solid construction", "substantial", and "build quality".

"Beats By Dre headphones teardown finds metal parts included just to add weight"

I know of a hardware manufacture who used to put concrete into their DVD players to give them that quality heavy feel

Are you sure that wasn't to dampen vibrations which might affect (or even themselves be caused by) spinning the disk and movements of the read head? (Same reason there's concrete blocks in the base of a washing machine)

The iPhone 4 with the steel frame was great.

IMO, the current iPhone is too light. Without any weight I feel like it might slip out of my hand or I might accidentally throw it.

> electric candles in churches could cut down on unnecessary wax us

I know your comment is a bit tongue in cheek, but an LED connected to an AA battery is enough to last a few days - IKEA sell a nice set that even flickers. I don't go to church, but I suspect the flame (fire) itself is symbolic.

It's a thing http://www.fatimamissionaria.pt/artigo.php?cod=3211&sec=6 You insert a coin and a candle lights up

I wish I had a more pithy comment with which to reply, but I'll have to make do with just saying that was just hysterical. I hope you meant it to be so.

>The primary issue with a larger mass is accelerating and decelerating it

It's actually friction, for electric cars. Regen is pretty effective at recapturing acceleration, so the energy lost in the wheels is the biggest factor.

> It's actually friction, for electric cars. Regen is pretty effective at recapturing acceleration, so the energy lost in the wheels is the biggest factor.

Mass counts much. It's not just about accelerating a still object (car) out of friction. But it's also about working against gravity (g). If the car's acceleration vector is at some angle with gravity (ie, when not perpendicular), more energy will be required to accelerate (when climbing slops), and to break (down the slope).

This is very much clear for aircrafts, and other flying objects.

Edit: Inertia is also a reason for energy loss in cars (and other moving objects), which increases with mass.

Regeneration recovers a certain percentage of any energy put into speed or altitude. No matter how long you spend climbing you get a good fraction of that energy back. In practice this is pretty quick, and even in stop and go you spend more time at around the same speed than accelerating and slowing.

Rolling friction loss is related to speed and is occurring constantly as you drive. That energy is just gone immediately, unlike inertia, which is stored. Say you spend 50% of your time accelerating and braking, and 50% keeping speed. If you regen 80% of the energy and accelerate with 2.5x the power you use to cruise, you're using twice as much energy on friction as accelerating.

The parent mentioned regen and that electric cars are good at it. That means: you don't accelerate infinitely. At some point you decelerate, and then you can regenerate the electric energy. However long you drive uphill, eventually comes the downhill of equal length and you regenerate.

I don't know how good exactly electric cars are here, but considering that a Tesla can work as a taxi in the city, it must be pretty good.

[edit: punctuation]

You can get a good % of regen if you slow down slowly, once the brake pads have to touch the rotors, you are throwing energy away.

Unless these batteries can accept charge faster, their extra mass won't be offset by more regen.

Except for the risks inherent in large quantities of mechanical inertia stored in a rotating mass, flywheels might seem an attractive option for rapid energy exchange.

Wouldn't there also be loss due to "rate of change of acceleration" or "Jerk" of which mass may have an effect?

The same reason city driving is less efficient?

Not really. Acceleration is related to torque so jerk is the rate of change of current in the motor. Current in an electric motor goes from 0-100% ~10k times per second (PWM), so the motor doesn't notice much difference.

>Current in an electric motor goes from 0-100% ~10k times per second (PWM)

That's just the voltage across the terminals. The reason why this works is precisely because current doesn't go from 0-100% with the voltage. PWM is relying on the inductance of the motor to keep the current the same as it would be if the average voltage was applied across the terminals.

That last paragraph was absolutely hilarious. Thank you :-)

I'm curious if these would work well in uninterruptible power supplies (whether under your desk or in the electrical room in your datacenter). As I understand, the potential explosive danger of Li-ion batteries makes them unfeasible for UPS applications due to the costs of meeting the hazmat regulations upon them, in addition to higher cost of lithium itself. If this solid state battery can be handled much safer than Li-ion batteries, and be made significantly cheaper, then perhaps we'll start seeing them in applications where LA batteries are usually used.

Excellent point. The long cycle life will make them very attractive, and weight is not a problem for a stationary application.

Do LiFePO4 batteries have the same hazmat issue, or are they just too expensive?

I know they don't have the thermal runaway issue other Li-ion battery chemistries have.

I'm no expert on this, but as a consumer, I wouldn't mind having a heavier phone if it meant a longer battery life. In fact, I much prefer a device with some heft.

A digital watch would benefit from those batteries. Smaller watch.

It sounds like it would _not_ have longer battery life, in the sense of "how many days can I go in between having to charge"

It sounds like the battery can withstand more charge cycles before getting crappy and needing replacement (eg, your phone might take 4 years instead of 2 before you have to replace the battery) -- way less useful

If you get the same energy in 1/3 that space (but 2.5x the weight), you could have a phone that is the same size as today but with 3x the time on a single charge in exchange for a battery that is 7.5x heavier. Phones are light enough that I'd probably make that trade.

Why? It seems that phones are space constrained, not weight, and this proposed battery is 3x better by space but 2.5x worse by weight. That would allow a 1 day phone to go 3 days right?

Even "space constrained" is arguable, depending on the context. We've had powerful, feature-packed phones no taller/wider than the screen and thin enough to fit in a tight pocket for years, and that's all anyone reasonably needs. But developers and gadgetphiles fetishize thinness to the point that devs are now actually removing important features, like headphone jacks and (on Android) removable batteries, to squeeze out a few more useless millimeters.

As long as those priorities remain, any power-per-volume improvements will be twisted around to serve pointless shrinkage rather than actually improving anything.

Some of this relates to the size of the phone in a case which add a lot of bulk and seem overly popular. But, another factor is larger phones need to be very thin to be comfortable in many pockets.

To the contrary, a long and very thin phone is hard to put into a tight pocket without the fear of bending and breaking it.

Do you really think the audio jack was removed because of thinness?

Have you seen the inside of a smartphone? Its not just about thinness. There is very little space for anything besides the battery.

Also, removable batteries and the audio jack get in the way of dust/water proofing.

You may think shrinkage is pointless, but that's clearly not what the market or the top designers think. Why do you want a giant, useless, 100+ year old analog port on your 2017 device? I don't. Its ugly.

Agree on the battery part. But...

> Why do you want a giant, useless, 100+ year old analog port on your 2017 device? I don't. Its ugly.

Arguing about aesthetics is futile, but I want the port because I find it useful, and don't measure utility by invention-age. Seems similar to judging a beer by the bartender's height.

I like this comparison, will steal.

> Seems similar to judging a beer by the bartender's height.

I'm puerile :)

>Also, removable batteries and the audio jack get in the way of dust/water proofing.

My Samsung Galaxy S5 proves you wrong on this.

>Why do you want a giant, useless, 100+ year old analog port on your 2017 device?

3.5mm jacks aren't 100 years old. 1/4" ones are. And I want one because my $350 Sennheiser headphones use a 3.5mm jack, and Bluetooth headphones sound like crap and Beats headphones are utter garbage.

While i agree that the port is useful and i want a phone with one, your comment about Bluetooth headphones sounding crap is ridiculous.

The Bower and Wilkins ones are decent, the BW P7 Wireless is the best portable headphone i ever heard, the integrated bluetooth DAC is actually better than the DAC integrated in my iphone 5s and huawei p9 phones.

I had the sennheiser momentum 2 headphones before them, also different AKG Headphones and the BW7 Wireless beat them on all aspects when it comes to the sound, in Bluetooth mode (they also have an optional cable included - they sound better with the bluetooth dac tho!)

Maybe that's true, but my experience from the other end of the price scale is that cheap bluetooth headphones are absolutely awful compared to cheap wired headphones. I'd love to be proven wrong on that, as I don't like the wires, but even when I've had bluetooth headphones that sounded tolerable, switching back to even the cheapest wired headphones felt like a revelation.

Personally, I care just enough about the audio quality that this matters, but that I'm not willing to pay for an expensive pair like the BW P7 (more like 1/10th of that price...), and in my price range.

Bluetooth won't be a good replacement until they can compete on quality across that whole price range.

>Why do you want a giant, useless, 100+ year old analog port on your 2017 device? I don't. Its ugly.

I presume you've removed the electrical outlets from your home for the same reason.

And the water faucets! And the drains! And the toilets! And the windows! And doorknobs! And doors! Heck who needs doors - we can just crawl in the windows.

Sometimes things invented 100 years ago (or 1000) are all we need. People don't evolve that fast.

There's an incredible innovation that can shrink a 3.5mm audio socket by over 30% in thickness. It's called a 2.5mm socket.

One of my old phones (the Treo 650 I think) had one of those sockets, and using an adapter to plug in 3.5mm earphones was pretty irritating.

More or less irritating than a Lightning-3.5mm adapter?

> Do you really think the audio jack was removed because of thinness?

That and to shill overpriced, easy-to-lose Bluetooth earbuds, yeah.

> You may think shrinkage is pointless, but that's clearly not what the market or the top designers think. Why do you want a giant, useless, 100+ year old analog port on your 2017 device? I don't. Its ugly.

How on earth is a tiny, inconspicuous round hole uglier than a big dangly headphone adapter?

That aside, this is exactly the problem I'm talking about. The "top designers" have decided that phones are fashion accessories first and working tools second. I like good design as much as the next guy, but good design is functional. A pretty tool that doesn't work properly is useless.

I think the audio jack was removed as a step toward not requiring cables at all.

You need to revisit your comment. A 3.5mm port with Bluetooth does not require cables any more than a Bluetooth-only device.

Except BlueTooth audio quality is terrible. No one is wrong to want something better, wireless or 3.5mm.

That's fine, but that has nothing to do with whether or not the presence of a 3.5mm jack makes wires mandatory. Whether or not the quality of the bluetooth stack improves with the removal of the 3.5mm jack is highly debatable.

There is very little space for anything because of the insistence on making the phone thin. Without the thinness fetish there'd be plenty of space without sacrificing the jack. Add even 1mm, and e.g. the area covered by a battery with the same capacity is drastically reduced. Just look at some older (thicker) phone batteries for comparison to the pancake batteries in newer phones.

> Also, removable batteries and the audio jack get in the way of dust/water proofing.

The same method used to dust-proof/water proof the USB apply exactly as much to the jack. And they also apply just as well for the battery compartment - nobody cares about making the battery compartment dust proof, after all.

I can say water proofing is never something I've looked for in any phone beyond being able to handle the occasional splash. Even then, if you look at the inside of devices with removable batteries vs. devices where the batteries are not intended to be, the main difference is that in the former there is usually an inner shell covering the rest of the components - overall the internals of the phone tends to be better protected. If you want to water-proof that inner compartment, then worst case you get shorts. Again, this is about thinness and some extent cost-custting - dust proofing and water proofing is a total canard since you still have wires crossing the boundary, and two more sets is not going to make a major difference.

> You may think shrinkage is pointless, but that's clearly not what the market or the top designers think.

We don't know what the market thinks, because there are no high end devices that sacrifice thinness for e.g. battery capacity as none of the big brands dare to even try to be different.

I've just gotten a Umi phone that uses a 4000 mAh battery (vs. more typically 2400-2600 for most of the mid-range MTK based phones) and it's fantastic to have that extra battery capacity, but it's a Chinese phone with little presence in Europe/US.

Give it a few more years and we may see if any of the smaller brands manage to grow based on their larger battery capacity.

There are a few others - you can get a decent quality Android phone with 6000 mAh, and one with 10,000 mAh. The downside is that the latter was built with the assumption that anyone wanting that much care more about battery lifetime than anything else, and so it sacrifices the screen quality for a lower power one too, and makes various other sacrifices.

> Why do you want a giant, useless, 100+ year old analog port on your 2017 device? I don't. Its ugly.

I found this hysterical after your appeal to the authority of "the market or the top designers". Outside of Apple, pretty much only HTC have taken that leap. The vast majority of "the market or the top designers" so far still insist on keeping the headphone plug. Maybe that will change, but I note that on my commute now, pretty much everyone I see with a new iPhone also drag along ugly adapters so they can use their old headphones.

If I know anything about cellphone manufactures they will simply use this tech to make the phone razor thin rather than increasing battery life.

I'd like to wager there'll be all kinds of phones trying to discover what the customer wants. I'm guessing, for the majority, it'll be neither of the extremes - heavy with max battery, or light weight with min battery - but somewhere in between those extremes

It has higher energy density than Lithium, so theoretically yes it could increase the battery life of your phone. For equivalent energy the size is 33%, so one could fit 3x the energy capacity into a cell of the same size.

until phone makers realise they can shave 1mm off the thickness of the phone by cutting the battery size by 66% (and they will)

Then we're back to barely-a-day-of-charge

Or 33% thinner and double the life. I'd take that trade, for sure.

But why not 0% thinner and 3x-3.5x times the life? Are we really plagued by thick phones right now?

The real reason is that if you make several million phones that a certain percentage is always going to explode, either by manufacturing defect or a user pierces the cell through accident. This might mean the difference between some light leg burns or your death and phone makers are not going to take the negative press of the latter scenario. Their only answer is better power usage.

One of the big advantages listed in the article is that these batteries don't explode like today's Li-Ions.

Maybe in a few years we'll look back at this time and wonder how people were ok with putting a bomb against their face every day.

and also how we drove vehicles powered by explosions? :)

I do not care how much about the weight of the batteries in my basement, as long as they are charged by the solar cells on my roof.

Storage of collected solar energy perhaps?

That would depend mainly on price. I imagine at this early stage pricing would be entirely speculative, but new technologies don't usually start out cheaper than established ones.

If it's fundamentally sodium vs. lithium then it's going to have huge price advantages at scale.

That's a matter of cost, not size. Mass is more important than volume for cost because transport depends on the weight primarily and because fundamentally more mass means more stuff. In the end you still have to pull x tonnes out of the ground.

Stationary utility scale energy storage.

Your solar and wind generation facilities now go to 100% capacity factor.

Maybe electric bikes and mopeds/scooters? Space seems to be a bigger issue for those than cars. And in the early days (and in some cases today) lead acid batteries were used. Lead acid had similar weight issues, but are much worse in terms of size and power, so seems like if folks were able to make that work, then a bike or scooter with this solid state battery could work.

I went on amazon to look at some product weights. There is an e-bike battery that weighs 6.5 lbs[1], and an e-bike that claims to have a shipping weight of 60 lbs[2]. So assuming 3x battery weight for roughly the same power, that means an extra battery weight of 13 lbs and a total bike weight of 73 lbs for a battery that could possibly fit in the frame (as opposed to be mounted on the down tube). So that is definitely getting on the heavy side for a bike but the bike in question is also relatively 'over-powered' as far as e-bikes go (25 mi self-powered range, 350 watt motor). A lot of the sleeker/higher end e-bikes are 'pedal-assist only' and already hide the battery in the frame. These bikes can get in the sub 40 lb range, and probably use 1/2 the battery that the one in the link does. So an extra 10-15 lbs is probably manageable and it would result in a bit more range while still being able to hide the battery in the frame (assuming a li-ion battery weight of ~3lbs, you would add an extra 6lbs to 'break even', or an extra 15 to double the power).

For scooters/mopeds, the math probably works out even better, as these are already over 100 lbs, and an extra 30-40 lbs won't really matter that much. And if you want to build a electric scooter or motorcycle that can go highway speeds, that extra weight can help with stability.

[1] https://www.amazon.com/36V-11AH-Li-ion-E-Bike-Battery/dp/B01... [2] https://www.amazon.com/Addmotor-HITHOT-Electric-Bicycle-Susp...

Voltage is irrelevant. You can put batteries in series.

It's not; it has practical consequences. Everything in a phone runs at a spectacularly low voltage compared to most electronics because the battery only has one cell. At small sizes it's simply not practical to make more cells.

Smart phones typically run lower than 3.7V so it's still not a big deal. The weight is a possible show stopper for cars but probably not smart phones (where size trumps weight) and of course they may be able to get the weight down by some kind of chemistry or materials magic (glass foam?)

Phones turn off automatically if the battery dips below 3 V, and this battery tops out at 2.7 V. It's totally possible to make it work, it just isn't terribly simple.

As for chemistry and glass foam, the voltage of a cell is determined by the electronegativity of the reaction in the battery. With lithium, it can never be very much above 5 V- atoms just don't pull on each other that hard. This already uses lithium, and the chemistry won't be able to improve much bast 2.5 V.

For any given chemistry, you can't increase the voltage without putting cells in series, because the atoms decide the voltage. Any tweaks to construction, electrolyte etc. can only increase the current, by giving it more places to flow.

"It's totally possible to make it work, it just isn't terribly simple."

Please, it's as simple as a three-component boost converter - one IC and two resistors. Same thing I use to bump 1.2V up to 3.6Vto run LEDs. It takes zero space (7x7mm total.)

Sure. You could use an SOT23 or a QFN like this: http://www.digikey.com/product-detail/en/texas-instruments/T...

That's 4 mm x 4 mm (more with passives, but not too bad), and hits a solid 95% efficiency at the normal load of an iphone, and is above 90% all peak loads. Heat dissipation will be fine, all parts cost about $1.20. Low EMI.

However, its still a dozen new components. It's a ~10% tradeoff somewhere and while that may be totally worth it, its not simple. Phones do not have square millimeters to spare.

>Phones do not have square millimeters to spare.

Actually, they do, when you're replacing the battery with one with 3 times the energy density. Use some of the saved space for your DC-DC converter.

Its like... adding a turbocharger to a car. Yes, it is possible. There are even kits, after a fashion. But it is still not simple.

Also, its not even at the stage of a hypothetical question yet. This battery would last about two weeks in an iphone under these load conditions. The only reason it "looks" possible is if you're considering a battery that is not this one.

If it's a true boost converter, it's also going to need an inductor somewhere. If it's really just driving an LED, it could be a charge pump, which uses capacitors instead. But charge pumps probably can't handle the current level that a phone requires.

"If it's a true boost converter, it's also going to need an inductor somewhere."

We use resistors as inductors. Plenty of wound resistors in teeny-tiny packages exist, that's how we have metal detectors with credit card-sized boards, the literal bulk of the unit is the frame and coil assembly and board housing + adjustment controls.

Older gas charge pumps can handle it, but they're bulky and they are lossy and generate a lot of heat.

what's the efficiency of that boost converter? how much energy gets dissipated as heat in that setup, and is that likely to cause a fire?

Modern boost converters have efficiency from 80% to 95%. They also operate at high frequencies – 1MHz or even 3MHz, which allows to make inductors incredibly small. Boost converters aren't a problem for a long time now.

Sure, but you can just put the cells in series.

Remember that '3.7V' nominal cells range from 4.2V down to a low voltage cutoff about 2.8V (and in practice will not be let too close to that DoD). So stacking two of these '2.5V' cells will probably give a 6-4V usable range.

Remember also that the electronics is in three groups: 1.8V (most of the processor), 3.3V (peripherals), and raw battery voltage (RF front end output power amplifier). The former two will already be driven by switchmode regulators and the latter is much more flexible.

Not just phones where volume matters, also small laptops. They simply need some weight to counterbalance the screen.

Everything with a mobile CPU inside has a switching power supply that could be adjusted to use 1, 2, 7, or 40V just as easily.

Really small devices do not have space for those, so ear buds may not be able to use this battery. But your phone, or watch, certainly can.

Sensors with Bluetooth / low power wifi. Lithium Ion batteries work for 5 years for our use case. If this improves that, that's less replacement.

Perhaps sationary power storage, like tesla's power wall, or an uninterruptible server power supply.

Would this type of battery be useful for grid storage?

Mobile phones

Laptops, maybe? The voltage is too low for phones, as is the power. That's why solid state batteries aren't used yet, they (non-research) can't match the power that phones and computers require.

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