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Tesla Acquires Canadian Battery Specialist, Hibar Systems (electricautonomy.ca)
195 points by reddotX 10 days ago | hide | past | web | favorite | 92 comments

This distributor’s page gives more color on Hibar’s business: http://www.unicontrols-asia.com/category/hibar-pumps/

In particular: "The pumps are used by battery manufacturers from all over the world for filling batteries with electrolytes, and have set the global standard in the battery industry."

A few thoughts on this:

* There's a slight monopoly danger of having so many batteries manufactured from one source, although Tesla would be better than say, an oil company.

* Can we please get standard battery form factors, voltages and connectors: like AA, AAA, C, D, 9 volt, etc, but in a larger size similar to lantern batteries and car batteries?

* Can we please get batteries with built-in protection circuits? I want to wire them in series or parallel at any voltage and have them "just work" and never explode. Bonus: please do this with solar panels as well.

* Can we please get batteries with prepaid postage or a recycling refund (similar to aluminum cans) that can be taken to any post office, propane exchange or even gas station for recycling?

> Can we please get standard battery form factors, voltages and connectors: like AA, AAA, C, D, 9 volt, etc, but in a larger size similar to lantern batteries and car batteries?

This exists already. 18650 is in widespread use and now 2170 is gaining traction. Each cell is already a standard voltage, 4.2V at the top end, 2.75V on the bottom end (or lower depending on whether you want to risk permanent damage).

> Can we please get batteries with built-in protection circuits? I want to wire them in series or parallel at any voltage and have them "just work" and never explode. Bonus: please do this with solar panels as well.

These also already exist. Tesla will never use them because the BMS handles that job, which is more effective and cheaper.

Tesla has the built in protection circuits. The more important thing is on top of that cool and heat batteries in extreme temps and when charging. That's why teslas don't lose range, and most other batteries do. latest gen from germany cars finally have cooling system, leaf still doesn't.

And connectors. There are multiple worldwide standards because companies keep pushing their own for attempt at proprietary advantage. J1772 is the worldwide standard for ac that everyone supports. It has a flaw of not going to high enough power. Tesla is the only company that supports upto 80 amps 220v. Most companies support much lower voltages, some barely 30 amps and 220 v. Current gen tesla support 220v and 45 amps (can't remember the exact number). There are multiple worldwide standards for high power dc. Chademo (Japanese standard, doesn't go to high enough power, only like 50kw), leafs support these in the us. ccs in europe is a successful cross company standard that everyone uses, including tesla model 3 and later. So good job there. The us stupidly has a different ccs plug. Not many cars support it.

Teslas own proprietary plug is better than all the standards, supports higher power. Only just now are there cars on the new euro high power ccs plugs that match and exceed tesla's powerful plug. My 2012 tesla model s car is basically better than all existing competitors in range, ability to charge, etc. The brand new cars from porsche (but you can't go out and buy one, coming soon maybe, the taycan has a higher theoretical charging speed, they need to build a charging network.

Tesla offered to share their plug tech to other companies if they agreed not to sue each other, but no companies took them up on it.

> J1772 is the worldwide standard

No, it's not. It's mostly just used in North America and Japan. The IEC 62196 "Type 2" connector is the standard in Europe and most of the rest of the world. And outside of North America and Japan, Tesla use the standard Type 2 connector on their vehicles, not the proprietary Tesla connector.

North America certainly has a big problem with the lack of connector standardisation, but J1772 is a big part of that problem, not the solution.

1) CCS has 7000+ stations in EU and as EU cars start to take over EV market share from JP ones you will see that standard dominate across the US.

2) Model S can charge at up to 200kW. Porsche Taycan can charge up to 270kW and they have said a software update will push this to 400kW-500kW. We still aren't sure what Porsche's superior 800V architecture is capable of.

3) Porsche doesn't need to build a charging network. They can use the existing CCS ones provided by third parties many of which are starting to rollout 350kW charging.

You don't necessarily want all batteries to come with built in protection. Today, you have the option of with or without.

Each protection circuit comes with a power cost. Consider the most basic protection: a resettable fuse (real protection circuitry is more complex).

If you put a resettable fuse on every battery in a pack that tiny voltage drop across a single battery will occur across each and every battery in your pack.

A small number of batteries and you wouldn't notice. But if you're looking at hundreds or thousands of cells it gets to be a major issue. Looking at string of batteries in series, if you draw a large current from the pack you'd find your pack voltage drops and you generate a lot of useless heat.

When building custom packs beyond hobbyist stuff it's often better to source (or design) your own battery management system than to rely on safety circuitry in each cell.

And that's not even mentioning the pack management and communications capabilities that custom pack- or string- based management circuitry would have.

Tesla doesn't manufacture the batteries, Panasonic does, this acquisition is strategic for Tesla to mitigate the impact of Model 3 sales falling far short of projections [1, 2] on its relationship with Panasonic. Elon and the Panasonic CEO had some tough conversations earlier this year [2], Panasonic has stopped investing capex in Tesla [1], and Panasonic has pivoted to other automakers long-term [3], particularly Toyota [4]

[1] https://asia.nikkei.com/Business/Companies/Tesla-and-Panason... [2] https://asia.nikkei.com/Spotlight/Cover-Story/Sparks-fly-Ins... [3] hard to find a singular link that back this up, note the constant drumbeat of agreements/movement over the last year and contrast with 1 & 2: c.f. https://www.google.com/search?q=panasonic+toyota&rlz=1CAUWRX... [4] https://sciencebusiness.net/network-updates/commission-clear...

It is an open secret that Tesla has been working on manufacturing their own batteries for years, and especially since Maxwell acquisition. This is the more likely explanation.. that Tesla is developing their own in house... and they don't need or want Panasonic's help.


I don't doubt Tesla wants its own battery operation (vertical integration seems to be a big thing in Musk's book), but I don't really see how Maxwell fits with that. They're a capacitor company. Sure sticking big ole caps next to batteries is great for instant power but it's not like the skill set of manufacturing one really translates to manufacturing the other.

The reason Tesla bought Maxwell isn't ultracapacitors, but their solventless dry electrode tech for making better and cheaper li-ion batteries. Higher energy density, no cobalt needed, cheaper/faster battery production.

Recommend reading up on it, it's fascinating and quite widely covered online.

It's a win on many fronts for Tesla if they can make it work.

> but it's not like the skill set of manufacturing one really translates to manufacturing the other.

They're not?

While batteries store energy in a chemical reaction and capacitors store it in an electric field; physically their construction is very similar.

Super capacitors, like batteries, have plates and use an electrolyte. They are also packaged similarly.


I would imagine there is quite a bit of overlap in manufacturing and chemistry.

>Can we please get batteries with built-in protection circuits?

I'd much rather have batteries fail in a predicable way than trust failure from abusive usage can be prevented (and then fail unpredictably).

Ah, the dream of all Canadian companies: get acquired by a bigger American one. I wish there were at least a few more Canadian mega corps to sell to.

If it had to be anyone though, glad it’s one of Musks moonshot companies. Uh, not his literal moonshot, figure of speech!

> Uh, not his literal moonshot, figure of speech!

Starship and its fins it uses for re-entry will need top of the line battery tech. The prototype Starship uses Tesla batteries[1], wouldn't surprise me if that continued to be the case

[1] https://twitter.com/elonmusk/status/1176586684751908872

I have two questions regarding batteries I often wonder about. Maybe the wisdom of the HN crowd can answer one or both of them:

Is there a theoretical limit on how much energy a rechargeable battery of, say, 1 kg mass can hold?

Can a rechargeable battery be discharged and recharged and afterwards be in the same state it was before the cycle? Or is degradation inevitable? Again, I am asking for the theoretical possibility. Not real life challenges to implement it.

The theoretical maximum is higher than gasoline(1700Wh/Kg[2]), and that's what matters:

rechargable Li/CuCl2 could offer 1166.4 Wh/kg[1], while recyclable, non-rechargeable aluminum-air could offer 5200Wh/Kg[1].

Some batteries may have 200K recharge cycles[3].

Innolith is talking about a battery with 50K recharge cycles[4], but for the grid.

They also talk abuot building a 1000Wh/Kg battery for cars.

But who knows , they're a startup, so we'll need to wait and see.

And phinergy, another startup working on recyclable aluminum-air battery - is planning to open a factory in India in 2020.





It’s important to realize gasoline is measured in thermal energy which is much harder to convert to useful work than electricity. A reasonable comparison cuts gasoline’s energy density in half at a minimum while a more practical analysis includes the much higher weight of gasoline engines.

> while a more practical analysis includes the much higher weight of gasoline engines.

Currently electric car batteries weigh far more than a gasoline engine - and the range is still worse. Saying the gasoline engine is heavy is weird when you're talking about replacing it with something significantly heavier.

The reasonable rough approximation ought to be comparing two complete power trains including stored energy.

For an AWD ICE car, that includes fuel, tank, engine, transmission, differentials, and drive shaft. For an AWD EV, that's two motors, batteries, and the rest of the cabling and infrastructure required for the batteries and motors.

I understand that and agree with you, but the wording of OP implied a gasoline engine is so heavy it would have a significant impact on the equation - with current technology that's really not true. You can find inline-4 engines in modern vehicles that weigh under 300 pounds, whereas the motor and inverter pack in the Model 3 weigh 350 pounds.

Even so, this is all trumped by the fact that the battery pack by itself weighs about 1,000 pounds more than the motor.

Those 300lb engines would be a poor replacement in a model 3 competitor. Plug in hybrids can get away with it, but at that point all 300lb could be used for larger battery packs.

> Those 300lb engines would be a poor replacement for a model 3 competitor.

Are you saying a 300lb engine can't compete with a Model 3 in terms of driving performance? Here's a 5+ year old engine that weighs 290 pounds, makes just under 300 hp and lb-ft of torque in a stock vehicle.


With a mild tune (software upgrade, about $1000) you can turn a Golf R into a 11 second 1/4 mile car (you can do the same with a GTI, but it's a lot more work because it's FWD). It will literally run laps around a Tesla at a racetrack because the Tesla will overheat.


Anyway, back to my original point - OP made a comment that seemed to me like the weight of gasoline engines was really important in comparing efficiencies - it's not. Right now gasoline vehicles are lighter, have longer range, and for many people are more convenient. I look forward to the day electric vehicles have improved enough that they are lighter, have longer range, and for many people are more convenient. But right now battery storage density is a real limiting factor in making that a reality, and the weight of the gasoline engine is nothing more than a second order effect.

If you feel I am wrong, please provide numbers/calculations in your rebuttal - it will make for a much more data-driven discussion.

> It will literally run laps around a Tesla at a racetrack because the Tesla will overheat.

Wow dude you're the king of misinformation. Why not link to a 2019 article reviewing Tesla Model 3's Track mode? https://www.motortrend.com/cars/tesla/model-3/2019/tesla-mod...

The Model 3 has a dramatically different thermal management architecture and does not overheat like the Model S did.

Your article is reviewing a feature that hadn't been released to the public yet (your article is also from 2018) and strikes me as a bit of a PR piece. It does mention an impressive lap time scored by the Tesla - which is great - but I don't see anything that says the Tesla can drive multiple laps in a row without overheating.

So far nobody has posted an impressive time for any Tesla on the Nurburgring - the track considered the gold standard for performance lap times for decades - and that seems to be because nobody can make it a single lap without the car overheating. I am aware that in the past month Tesla has been making a significant effort to post a good time, and they still haven't done so even with a custom vehicle.


If you can show me a video or article of a Tesla racing 10+ laps in a row at any track without issue, or even doing 2+ fast laps in a row of the Nurburgring let me know. I just googled and couldn't find anything, other than anecdata of Teslas overheating and going into limp mode.

> article is reviewing a feature that hadn't been released to the public yet

Since that article is about "track mode", you should be aware that is has been shipping to the public since late 2018.

Your suggestion would be a horrific fit for a mainstream car in the model 3’s category. Fuel economy, emissions, and long term reliability are why they don’t put an engine like that in a Honda Accord.

In terms of real world preference, EV’s and plug in hybrids low speed handling characteristics are vastly more useful than top speed. So the 200hp Honda Engine is arguably undersized even in a lighter car.

A Tesla Model 3 usually sells for something like $50,000, I'd guess - it's not competing with a Honda Accord. This article is a year old so it's outdated, but it suggests an average sale price of $60,000 for the Model 3. This clearly puts it in the luxury/performance price bracket.


Apart from that, the EA888 engine I mentioned is used in the VW Golf, the 7th best selling car in the world.


The engine is considered highly fuel efficient, rated well above 30mpg for most variants and many people report >40mpg in real world usage (obviously this data will be biased towards higher numbers).

The emissions, however, are supposedly great but I don't trust VW at all on this front so I'll just assume they're doing something shady. They are being legally sold in California though, which is really the highest emissions bar there is, so I'm not sure what you'd expect from them (again, assuming they aren't doing shady shit).

And unusually for VW, this is considered a reliable engine. It's been around and iterated upon for much longer than any Tesla.

There is no apples-to-apples comparison between electric and gasoline vehicles, but claiming one of the most highly awarded engines in recent history is lacking in performance is like claiming Teslas are worthless in cold climates - it's more rumor than fact.

I personally know people considering a mid tier Honda Accord vs the base model 3. The numbers they have run provide similar lifetime costs, though clearly many early adopters are less price conscious. Historically, Tesla was not going to make a base model when their was more profit from manufacturing a more expensive car.

Back to that IC engine “With a mild tune” is an issue. You can get reasonable performance on a tiny hatchback with the stock 149 bhp EA888 but that’s not going to cut it on a midsized sedan. Want more performance from the same basic hardware and you will make some real sacrifices, weight, fuel economy, engine life, etc one or more things need to give.

Pretending otherwise is to suggest vast numbers of automotive designers are idiots.

I feel like you just ignore all the numbers I write and invent new ones. A stock Golf R with an EA888 engine makes 292 hp and 280 lb-ft of torque - significantly more than any Accord you can buy new. A Golf R with a mild tune (just software) will generate closer to 350 hp, and moderate-serious tunes start around 400 hp. They also use this engine in their Passat, which is a mid-size sedan which competes directly with the Accord and weighs about the same.


I'm sorry, but at this point I'm just going to say you have no idea what you're talking about when it comes to IC engines and exit this thread.

You need to be making an apples or apples comparison for different numbers to be meaningful.

The base golf gets 25 city / 34 highway a Golf R gets 22 city / 29 highway. With a mid tune that golf R gets even worse mileage. These numbers drop further when you talk about a larger car with more wind resistance or weight. https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform...

Meanwhile the larger Honda Accord is getting 30 city, and 38 highway. https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform...

Taking a 25+% cut to fuel economy to use a lighter engine is a really bad tradeoff for most people. Especially when the point of this discussion was talking about fuel density comparisons.

On top of this IC’s also need a much larger and more complex transmission among other things which should be included in the weight comparison.

Yup. I drive a lot and don't care much about performance as long as I can get up to highway speed on the on-ramp. Fuel economy, maintenance, longevity all matter a great deal.

Could they not have meant all that is included with gasoline engine cars? I didn’t interpret their statement as to be taken literally to strictly including the weight of engine alone.

The parent was specifically talking about energy density of gasoline versus batteries in Wh/kg. The battery weight is already considered.

Parents implied point is that something like miles for functional equivalence / energy unit denaity is much more telling. The ICE is like 37% efficient while battery is >90%, so while hydro carbon fuel is more energy dense, the usable density is considerably less than it's raw energy content due to waste.

The battery is not the same thing as the motor. He’s saying that a motor is lighter than an engine, and this somewhat offsets the fact that batteries currently have lower energy density than gasoline.

Fascinating. I’m always intrigued in these style of answers. Where do super-capacitors fit in this?

Supercaps can provide higher peak energy flow, either for acceleration or regen. They can buffer the battery from rapid energy flux.

I doubt very much they are going to actually store even 1kWh of total energy, because mass storage isn’t their strong suit.

At least a 10x factor below.

A table you may be interested in:


>> Fascinating. I’m always intrigued in these style of answers.

Me too. Does anybody know a technology site/community, focusing on the theoretical limits of what various technologies could do, and how do they work , instead of the day to day news?

The stackoverflow family I’d sited is good for discussions like this and is often nicer than the halo site when it comes to inclusion of questions (I use SO everyday but trying to give back by answering a questions or even asking one I have had not so great experiences). I really like the astronomy and physics exchanges.

That wouldn't be a huge problem, and probably much better for the world if we "gased up" with aluminum

Aluminum requires huge amounts of electricity to produce. Hopefully that electricity isn't coming from fossil fuels.

However it does appear to be highly recyclable, at a fraction of the energy cost.

> Aluminum requires huge amounts of electricity to produce.

That’s kind of the point. If you can produce aluminum efficiently (i.e. reduce Al2O3 to aluminum metal without using much more energy than the theoretical minimum) and then oxidize it back to Al2O3 efficiently in a car, you have a battery that stores a huge amount of energy.

There is a rather spectacular non-battery use for this energy: thermite.

I can't remember where I read this (busy at work so, sorry, no source), but:

There's a production/re-use cycle in Europe wherein Aluminium is processed and smelted in Iceland, turned into ingots which are sent to mainland Europe to be manufactured-with, and then resultant used product sent back to Iceland for melting down and processing back into ingots.

The point being: Iceland uses geothermal energy to work Aluminium, so the entire process is one grand re/charge cycle of a significantly-used and energy-dense process.

Next step - small, modular fission power sources for the likely-hydrocarbon based and heavily-polluting ships transporting it all back and forth.

The beauty of electricity is that it can come from anywhere. And you don’t have to change anything in your process to change source of electricity.

Electricity is also much easier to transport over long distances, using high voltage DC lines, than it is to transport oil or gas via pipeline or truck.

And oil is much easier to transport over really long distances on tanker ships.

Only if you neglect the huge externalities of tanker ships, with the extremely dirty fuels they burn and the occasional catastrophic spills.

If you can have batteries with higher energy density than oil, why not fill up a ship with batteries?

Because A/C lines are more efficient than either oil or batteries.

Not over ocean distances though?

and can then be burned to make electricity

Batteries will also burn under the right conditions!

What about volumetric density?

"It is not feasible to get much more energy into a material than 1 eV per atom. Most solids have atomic weights of 30 GeV/c^2 [*] which yields E/m = 3x10^-11 c^2. When you convert this into the more human Watt-hour/kg, you get 850 W-hr/kg. "


I believe.. this is true, but not 100% sure. However the limit is higher with air batteries... as stated in another answer. The energy density of gasoline is high because it uses air intake for oxidation.

Also... part of why rockets are so big is because they also don't use oxygen from the atmosphere, they carry their oxidizer in the rocket.

This is an orders of magnitude approximation.

Tesla Model 3’s batteries are 207 Wh/kg. It strikes me as so close to the limit, whereas we usually are an order of magnitude under, in physics.

At one point the only improvement beyond the physical barrier will be to throw electrons into a void sphere and call that a battery.

An efficient (power density within factor of ~ 1e6 of the ideal mc^2 power source) EV battery doesn't need to be rechargeable, because the battery capacity will outlast the vehicle.

Approximately same goes for stuff we already know how to build, vehicle applications of nuclear batteries and reactors. Although IIRC for practical reasons nuclear refueling is done ever 10 years or so in terrestial applications.

Wait, what? It sounds like you’re saying if cars had fusion reactors for engines then we wouldn’t need rechargeable batteries?

Yes, we just need to restart DeLorean production...

I'm not sure how far we have studied the miniaturization of reactors. There were some designs for airplanes and cruise missiles in the 50s. And there's the current Russian missile (https://en.wikipedia.org/wiki/9M730_Burevestnik). A paper at https://aip.scitation.org/doi/abs/10.1063/1.1358022 claims that 60-80 kg reactors might be possible.

Interestingly your two questions point towards a trade off in battery design. Current research is adding more silicon to the batteries to increase energy density but doing so makes the battery degrade.


"Silicon shows promise for building much higher-capacity batteries because it's abundant and can absorb much more lithium than the graphite used in current lithium ion batteries. The problem is that silicon is prone to fracturing and breaking after numerous charge-and-discharge cycles, because it expands and contracts as it absorbs and releases lithium ions."

Another tangential question I've been struggling with is: is there a human limit to a power density we'll tolerate? Any sufficiently powerful battery is a defect or bad actor away from becoming a weapon. We already see defects in lithium batteries shaping airline policy, and the devices we're talking about are peanuts if we want to enable all our sci-fi dreams.

It depends on how easy it is to release the energy. A full petrol tank already contains a scary amount of energy, but you can't release it instantanously since it is bottlenecked by oxygen intake for combustion. Explosives bring their own compact oxidizer to get around that problem.

A chunk of uranium-238 contains a lot of energy but it is only fissionable but not fissile, so you need an external fast neutron source to extract that energy. Comparatively it is a fairly safe energy source for its density. Similarly there are some metastable nuclear isomers that can theoretically be stimulated to release their energy with high energy photons with a precise frequency and would otherwise release their energy relatively slowly through their natural decay modes.

And I think the difficulty of turning a hypothetical portable fusion power plant into an explosive device should be evident from the difficulties of keeping current experiments running for even a few minutes.

I just though of an interesting twist on subcritical reactor. What about smelting a californium neutron source together with the fuel? We get a much cheaper RTG alternative with near no need for regulation.

Any nuclear scientists here?

There is a power limit already in place for batteries you can carry on airlines and IIRC it's 100 Wh.

As for weaponizing batteries, pretty sure bad actors have been able to cook dangerous bombs at home for decades that can inflict magnitudes more damage than a battery could ever do. So battery based bombs won't be a thing for the near future.

That is because of the current lithium chemistry batteries. A more stable battery that wont blow up so easily after some damage wont have the same restriction

> Is there a theoretical limit on how much energy a rechargeable battery of, say, 1 kg mass can hold

A sufficiently high energy density will collapse into a black hole, so a theoretical limit on ordinary energy storage definitely exists. But it might still be possible to use black holes since they radiate energy as Hawking radiation:


A battery with 1 kg of mass would only collapse into into a black hole if it is very small. A bottle of water is 1 kg and I never saw one collapsing.

Hence why I said energy density.

It helps to simplify the problem into a more fundamental thing instead of focusing specifically on batteries.

Essentially, all practical energy storage can be thought of as putting some sort of strain on chemical bonds. That is, you're taking things away from a low-energy configuration to a high-energy configuration and back to store and retrieve the energy.

The insightful part is that all energy storage systems (aside from Nuclear) are fundamentally this! They're all made of matter, and they all "strain" chemical bonds of one type or another.

People think of "batteries" as something special, but they're fundamentally the same as explosives, compressed gas cylinder, superconducting magnetic storage, flywheels, or whatever.

All of them are limited by chemical bond strengths and start going BOOM if you push them too far.

Explosives... explode if the stored chemical potential energy is too great. A lot of research goes into finding novel compounds that approach such limits as close as possible without actually going bang.

Compressed gas cylinders can store energy, but explode when the pressure ruptures the walls -- which have a tensile strength dependent on the chemical bonds of the material used to make them.

Magnetic storage is an exotic approach, but used in MRIs and some power stations. The ultimate storage limit is that strong magnetic fields produce significant forces that can rip even steel apart.

Flyweels are typically made of materials with high tensile strengths to allow them to be spun up to higher RPMs. Again, the tensile strength depends on the internal chemical bonds of the material.

In all cases, the upper limit is ultimately bounded by the available chemical bond strengths of the known elements, one way or another.

There are only very few ways past this limit. Anti-matter storage is probably the most "practical" energy storage method currently known that significantly exceeds chemical bond strength limits.

In practice, separating chemicals helps a lot. Liquid fuels can store much more energy than explosives. People think a stick of TNT has a lot of energy, but a candle the same size releases vastly more when it burns. There are grid-scale battery systems that rely on this approach, using tanks of chemicals to keep things apart.

Still though, the maximum energy you can recover from a fuel and an oxidizer is limited by the difference in chemical bond strengths between the reagents and the end product. I'm not quite sure what the maximum possible energy release is, but chances are that it's whatever the Caesium-Fluorine reaction produces, or close to it.

PS: This is why I chuckle when people are shocked to hear about exploding phone batteries. Well... duh. That's literally what a "high capacity battery is", it's a chemical system that's packed full of energy. Literally ready to explode, held back from the brink only through careful arrangement of its constituent parts.

Username checks out.

Thank you for the insightful comment.

if by battery you mean box with two wires, then for the first one answer is yes. for example batery storing energy in fast spinning mater. for second one i assume theoretical energy dencity limit is much greater than anything that we might need. but for chemical bateries i would also like to find out answers to your questions.

I mean for batteries in general. Independent of the technology.

For the spinning matter battery, the limit might be when the whole matter of 1 kg spins at the speed of light. I wonder if it matters how big the radius is with which it spins around the center?

For a non-rechargeable battery, I guess the limit is 1kg * c^2. As Einstein postulated that e=mc^2. And that guy was right more often then not. Is that also the upper limit for rechargeable batteries?

How long could a Tesla drive on 1kg * c^2?

Yeah, the absolute limit is c^2 if you've got 50-50 matter-antimatter. The efficiency however is brought down by the difficulty of _producing_ antimatter in the first place. A more popular hard-sci-fi concept is black hole engines; a 600kt black hole sprays out a hundred petawatts of Hawking radiation, and the fuel is whatever you've got lying around. That still has issues around energy _capture_, since the radiation is going to be ridiculously high-frequency. The best way I've heard of to dodge those issues is the 'Penrose process', where the fuel is the black hole's rotation and you get good ol' kinetic energy out. That can at most get you 20% of the mass-energy though, and there's a bunch more small print.

20% is the energy gain of particles involved in each energy transfer, total energy available is 29% of the black hole's rotational energy according to Wikipedia.

> For a non-rechargeable battery, I guess the limit is 1kg * c^2.

Assuming it is antimatter-based you can double that capacity by consuming air. But that just turns it into a fuel tank for an internal annihilation engine and hardly qualifies as battery anymore.

This is Tesla we’re talking about. They’d probably ship this with a footnote in the owners’ manual: “Any use of this doomsday device for purposes other than a battery is prohibited. Do not operate outside containment field.’

You all really took this question and ran with it in a way that totally avoids answering the practical question at the core — how good are these batteries going to get over the next 20 years?

The answer is really, really good. Fast charging, long rang, 1 million mile lifespans.

Add on top of that the ability to connect into a smart grid and earn money by buying energy off-peak and selling on-peak, and the ability to double as an emergency generator for your home.

Aha! So the most efficient mass based rechargeable battery would be one that while loading creates antimatter and while being used burns that antimatter with air (or other stuff) it takes from the environment.

> hardly qualifies as battery anymore

Why not? There are plenty of battery technologies that use air as an oxidizer.

It follows from the definitions of a battery and a cell:

> battery: a container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power.

> cell: a device containing electrodes immersed in an electrolyte, used for current-generation or electrolysis.

An antimatter reactor would not be a battery because it would not contain any cells. Additionally, because it converts nuclear energy into useful power, not chemical energy.

1kg * c² = 24 TWh.

Supposing a Tesla averages 200Wh/km, then it would drive ~ 10¹¹ km (4 light-days, or around 600 times the earth-sun distance... which is a lot)

At least in the medium-term future we would at most be able to use is Hydrogen->Helium which would yield 6.45 x 10^14 Joules [1] which is equivalent to 179 GWh which at 200Wh/km would be 8.95*10^8 km.

That's still enough to go 20.000 times around the globe and longer than any car is known to have lasted so far[2]

[1] https://www.phys.ksu.edu/personal/wysin/astro/review9/p4.htm... [2] https://en.wikipedia.org/wiki/Car_longevity

If Wolfram Alpha is right, then 10^11 km is 2 million times around the earth:


Shows the potential of batteries. Charge your one kilo batttery to drive around the planet two million times.

It would be a misnomer in common parlance to describe nuclear fuel as a battery (mass > energy conversion). The broader language to describe this is ‘energy storage.’ E.g. oil is stored solar energy over millions of years, batters are stored electrochemical energy, flywheels are stored mechanical energy, etc.

> For the spinning matter battery, the limit might be when the whole matter of 1 kg spins at the speed of light.

Of course, it's theoretically impossible for the matter to spin at the speed of light, and any actual material will tear itself apart at speeds far below c.

> Is there a theoretical limit on how much energy a rechargeable battery of, say, 1 kg mass can hold?

As with most things, you can find some fairly irrelevant theoretical maximum. It's fairly irrelevant because real life implementations will invariably involve compromises. It can be nice to know the limit, but it's not terribly useful for making an actual device.

For rechargeable batteries, it's not just about how much energy the battery can store, but how fast can you charge and discharge, what's the recharge efficiency like, does it degrade when recharged, can it be deep cycled without adverse effects, how sensitive it is to physical and electrical disturbances, does it have high or low self-discharge and so on.

Different applications have different demands and so there's usually not a single optimal battery technology.

A lithium/air battery is 40.1 MJ/kg. There are people working on aprotic liquid electrolytes that could be used with secondary (rechargeable) cells with a metallic lithium anode.

I’ve always wondered what the energy density of superconducting rings is? I guess no one has ever tried to optimize one for weight or size.

> I am asking for the theoretical possibility.

That's a nonsense question then. Theoretical limits on power density will revolve around unobtanium and matter-anti-matter explosions; it's off topic as far as I'm concerned in a thread about Tesla acquiring a Canadian Battery Specialist, a company that is engineering batteries in the real world where practical limitations of materials science and chemistry are the ingredients, not your fantasy of what amount of energy one could theoretically store in a given volume if all of natures laws would be lifted. For reference, just the kinetic energy of a couple of liters of Neutron star alone should also figure into such discussions as well as a whole bunch of other nonsense.

> just the kinetic energy of a couple of liters of Neutron star alone should also figure into such discussions

That would have a mass _substantially_ higher than 1kg...

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