Hacker News Reader

Comment by gibolt | Hacker News Reader

Current mass produced batteries, which tend to hover around 260-300 Wh/kg. Higher density (but still under 500) are available, but in far smaller quantities for a very high cost.

The exciting part of this announcement is that if anyone can scale manufacturing, it is them.

View on HN

Really it is encouraging for advancement areas like this.

Reminds me of the "revolutionary battery checklist": https://news.ycombinator.com/item?id=28025930

edit: removed the paste of the checklist because of spam.

“No week goes by without a revolutionary battery technology”

- Engadget, circa 2010

While this is true, a tiny start-up with big claims is different from the world's largest battery manufacturer (CATL) already spooling up production with the intent to scale.

And that is why batteries have become so much better now than they were 20 years ago.

Eh, not really. Most "battery breakthrough!" press releases are about some new exotic chemistry while most mass produced battery improvements in the last 20 years have come from incremental improvements to existing chemistries and better packaging.

Meh, the devil's in the details with a lot of those announcements. A surprising number of them are things like... it will be 50% better 5-10 years from now!

That's actually incremental improvement if you think about it in annual improvement terms.

It is, except for the fact that the future isn't guaranteed, so there could be unforeseen problems with scaling up, and that 50% improvement never gets delivered. As mentioned upthread though, CATL has expertise in that area, and "end of this year" is so a trackable claim, unlike the claims about gallium-based batteries.

I agree. Its also not uncommon that the "old" tech improves incrementally during the same timeframe, mitigating the seeming impact.

Hard carbon anodes were one of these "exotic" new elements, but are now just standard.

Silicon anodes will be the same.

Sodium ion still has shills screeching about how it'll never come despite being last year's news.

Lithium Manganese batteries are another one of these exotic chemistries that arrived without fanfare.

Have they? Other than lithium based batteries getting cheaper per kilogram so that year by year, more battery use cases have switched over from inherently worse chemistries? Even just ten years ago, eneloop were still the hot thing for many applications outside of laptops, mobile phones and the odd Tesla (ten years ago was when Model S was still the fresh new successor to the converted Lotus)

Is eneloop not still very much a thing? Maybe not the brand, but the technology. The vast, vast majority of consumer devices using standardized battery sizes are AA or AAA, and that means NiMH. To go lithium means 18650, and I don't really see much of that happening outside flashlights and other niche products.

Why does going lithium mean 18650? 14500s have always existed. I think there’s even smaller than that but I haven’t personally checked in a bit.

Form factor smaller than 1865 with energy dense formula is rare. Chinese made LFP but only a handful of mfgs make them anymore. So size doesn't matter, but it basically matters :D

LFP is going to be manufactured in north america soon

Nothing except flashlights and yard lights seem to use them either. Probably because they're not exactly safe enough for frequent swapping applications, consumers will drop them on their tin foil crack smoking rig and make a fire or something.

There are many companies making rechargeable lithium batteries in AA and AAA form factors. I have a few dozen I use for my door lock and Xbox controllers.

Internally these are a pretty normal small li ion or lipo battery (3.70 to 4.2VDC range) and a DC-DC converter to output 1.5V

Sure, if a device uses the form factor, then eneloop or the same approach by a different brand are even more ahead of pre-eneloop NiMH than they used to be: all the high-current use cases that were the weak spot of eneloop have long migrated to lithium-based.

But AA and AAA are increasingly rare not only because of price but also because of the ubiquity of USB charging, and because of the way the powerbanks that USB charging enabled weakened the "carrying spares" argument for AA a lot.

In essence: yes, the vast majority of consumer devices using standardized battery sizes continue to be AA or AAA (if we can agree in ignoring the ubiquitous CR2032). But costumer devices that use interchangeable standard size batteries have become super niche, at least outside a few fields where you expect years on a set of batteries. To go lithium means going fixed battery (unless you identify with the performance flashlight subculture, again something I very much agree with)

Lithium mostly exists as pouch cells in consumer devices, standardized batteries in general are rare. AA/AAA is mostly used on extremely cheap stuff, or stuff that one expects to last 5 years or more so nobody cares about recharging.

I hope we eventually get a consumer friendly standard for lithium though. It could be so much better than cylindrical cells, we could have all our cheap gadgets using micro versions of the power tool slide on shoe concept or something. Kinda unbelievable the ISO isn't trying to standardize prismatic type cells.

Cheap cynicism is fun, but Wh/kg has been steadily increasing since the '90s https://arstechnica.com/science/2021/05/eternally-five-years...

The real question is, will this lead to reduction in cost?

If yes, I hope they open-source it so that the fight against global warming can gain some momentum across the globe.

Cost is just one of the interesting dimensions. For various kinds of transport energy may be more important than cost. I would be prepared to pay significantly more for an EV if had range of 1000 km rather than 500.

I think I'd prefer half the battery weight.

What battery pack that I can buy right now is 300Wh/kg? Sincerely curious because that's 50Wh/kg above what people are using in some very expensive UAVs.

Amprius has 400+Wh/kg that are commercially available. I'm sure they ain't cheap, but the tech exists.

https://amprius.com/products/

Edit: well, I'm a dummy and OP said mass-produced. Sorry.

UAVs also have higher current requirement, and that means more weight "wasted" for chonkier electrodes Car batteries aren't pulling 50C worth of current

Don't car batteries also have very high current requirements? Turning over an engine takes an enormous amount of power.

GP is probably talking about EV main batteries, not the lead-acid 12v accessory/starter batteries.

Most batteries that run starters are not energy dense, they're typically standard lead acid batteries.

FWIW, to provide the 225 amps (for a V8 starter motor) a Tesla car battery would only need a discharge capability of 3C (1C being around 80 amps), which is within its rated capabilities. This is also for batteries which provide higher voltages, so I'm vastly overestimating the C rate required.

C is the unit for charge/discharge rates, and is based off the capacity of the battery.

Sure but it's not about starter motors - these batteries power 400kW motors, that's a lot of power.

That's why how much power an EV has is closely related to the size of the battery. 400kW from a 75kWh battery is a little over 5C.

Honest question, though: does "Turning over an engine" (as an earlier commenter typed) have actual meaning for an EV?

No, it is referring to what the starter motor in an ICE vehicle does. It was most likely a misunderstanding, but it is more similar in that it pulls very high loads like a drone battery does.

Traditional ICE starter batteries are optimized for this cold-cranking power rating, but they only have to deliver this for a matter of seconds before being recharged. They are not designed to deliver this continuously nor to ever be operated at low states of charge.

Conversely, a BEV traction battery has to support a wider range of loads at any charge state between its minimum and maximum charge levels, in order to have decent driving range. Like a starter motor, the BEV is not going to sustain high power output for very long, since a car only takes seconds to accelerate to legal road speeds. After that, it requires continuous output at lower power levels to maintain a cruising speed.

Even with lead-acid batteries, there are regular starter batteries and then there are deep-cycle batteries which have far less cold cranking amps but more durability when depleted to low charge states before being recharged.

The low density of lead-acid batteries is what makes them unsuitable for mobile applications. They might have 30-50 Wh/kg while various lithium ions might be 100-300 Wh/kg. And now this announcement is talking about 500 Wh/kg so 10x the best lead-acid batteries...

This person seems to be getting downvoted but they aren't totally wrong, electric car batteries are massively paralleled so that the amperage draw per cell is kept to a reasonable figure. They are confused about cranking amps to turn over an ICE vs. batteries used in all-electric cars.

The 18650 Panasonic cells used in an older Tesla model S for instance are rated at only 10A draw per cell as their nominal 1S voltage (4.20V when full).

Starter current is ~150-200A at 12V.

At say 30C you'd only need 7Ah lithium batery

It'll take time (maybe significant) before these batteries are available for direct purchase. The problem is demand current outstrips supply. Every high capacity battery already claimed, in tesla's case for their cars and grid storage applications.

CATL pushing this sort of capacity, though, is great news. It certainly will accelerate availability.

Buy a Tesla Model Y and you'll have just under 300.

Very expensive UAVs use lithium polymer battery packs with continuous discharge rates on the order of 80C and above. To get higher energy density, look for lithium ion battery packs or lipo packs that reduce discharge rates to trade off for long-term storage capacity.

Compare to the discharge rate vs. energy density tradeoffs of plug-in hybrid EVs versus battery-only EVs: A Chevy Volt PHeV has a 16 kWh pack and 87 kW motor, a Chevy Bolt has a 65 kWh pack and not a 65/16x87=350 kW motor but 149 kW.

Based on Google's specs[0], the GMF5Z battery in the Pixel 7 pro is 18.96 Wh and 65 g, which is around 292 Wh/kg.

[0] https://support.google.com/product-documentation/answer/9682...

Battery people keep comparing apples, and oranges.

Battery pack energy density, battery, single cell, cathode, and their rated, nominal, and absolute capacity are all different things.

A single cell will always have > absolute capacity than the capacity at which the safety limiter will cut-off charging, and that will be > than the capacity to which BMS will charge/discharge the cell in daily use.

It may well be possible for a cathode material to excel in a small pouch cell, but have terrible thermals preventing its use in larger cells.

The design of a battery for a phone is nowhere near the capability of C rate and discharge amperage needed to power multi hundred watt load electric motors. Totally different thing.

Those are some very portable goalposts.

UAVs have high C rates and high durability.

EVs or even aircraft don't need anywhere near 40C.

Nobody is using 50Wh/kg in UAVs; even 150C racing drone batteries are higher energy density (~135Wh/kg for Tattu R-line V5 1200mAh 6s, 195grams)

Read what I wrote again, I said 300Wh/kg is 50Wh/kg above what's used in expensive UAVs. There are setups out there using high amperage Panasonic cells at 250Wh/kg for 12S systems. You build a pack with 12S strings of high amperage rated Panasonic 18650 or 20700 and then parallel multiple of those strings together for large capacity (such as for something the size of a freefly alta X).

A small quadcopter that uses a gensace/Tattu 1200 mAh lipo pack is not an expensive uav. I think everyone who uses hobby size lipo knows their specs around 135-160Wh/kg.

Any BMS that you can recommend for this panasonic setup?

Reply on news.ycombinator.com