Why is everyone trying to build a solid-state battery? • Hacker News Board

Re: Why is everyone trying to build a solid-state battery?

#121

Post by K0balt » Thu, Jul 30, 2026, 5:04 PM UTC

csours wrote: post #75

ranger_danger wrote: post #74

Earlier quoted context omitted.

That's a huge assumption that won't always be the case though. A gasoline tank with a small hole in it is a lot safer than a liquid-electrolyte battery with a hole in it.

Yes, that's what makes it interesting. Interesting discussions about energetics are best had from a distance.

I can remember several situations where “a little bit of gasoline” caused a lot of problems. It’s a relative term. You need a lot of air to make it really shine, but “a little bit of gas” goes a long way lol.

Re: Why is everyone trying to build a solid-state battery?

#122

Post by jarbus » Thu, Jul 30, 2026, 5:06 PM UTC

enslavedrobot wrote: post #5

Solid state batteries come in several flavours. Most of them don't stop dendrites. The flavour you want is polymer, single ion conducting solid state with an ion transport activation energy below 10kJ/mol at room temperature and no phase transitions from -40C to 80C. That is the holy grail of SS batteries.

I’m still a novice on the material science behind it, but what is QuantumScape lacking here if anything, and why is it a dealbreaker?

Re: Why is everyone trying to build a solid-state battery?

#123

Post by K0balt » Thu, Jul 30, 2026, 5:08 PM UTC

lightedman wrote: post #60

vikramkr wrote: post #36

Earlier quoted context omitted.

Liquid gasoline does not have anywhere near the energy of TNT, or even a battery for that matter. It contains basically zero releasable energy. It needs oxygen or another oxidizer to react with to actually release any energy. TNT and batteries' energy density calculations include the oxidizer and the oxidizer is in close proximity to the fuel (molecularly so in the case of TNT). If you 10x the "energy content" of gas…

"Liquid gasoline does not have anywhere near the energy of TNT," Energy density of gasoline is approximately 44 to 45 megajoules per kilogram. Energy density of TNT is approximately 4.184 megajoules per kilogram.

A snickers bar has nearly 5× TNT’s energy per kilogram—TNT merely has the habit of being extremely impatient about releasing it.

Re: Why is everyone trying to build a solid-state battery?

#124

Post by deckar01 » Thu, Jul 30, 2026, 5:09 PM UTC

thelastgallon wrote: post #108

deckar01 wrote: post #35

The Two Bit Da Vinci YouTube channel has a good video on solid state battery fundamentals and a deep dive into a battery company (ProLogium) that has demonstrated manufacturing at scale. https://youtu.be/xQFVIs4leig?si=iOOt5gg_2MJAIoFR

BYDs battery stress testing: https://www.youtube.com/watch?v=WPTgg3joL5E

Those use liquid electrolyte cells and the video is more promo than rigorous testing.

Re: Why is everyone trying to build a solid-state battery?

#125

Post by Borealid » Thu, Jul 30, 2026, 5:10 PM UTC

RetroTechie wrote: post #78

tflinton wrote: post #69

Earlier quoted context omitted.

High density batteries allows us to have dramatically cheaper electricity. Think of it like this, what happens when electricity is 1/10th the cost? Beyond what others have pointed out (electric airplanes, cars that drive thousands of miles), costs for everything would drop as energy is a core driver of it in every good you consume. If you can pull energy where it's very cheaply available and store/transport it anywhe…

Batteries are not power sources, but storage. The energy still has to come from somewhere, and power generation won't magically become 10x cheaper overnight. No matter how cheap battery storage becomes. But it IS crucial for removing bottlenecks & replace fossil fuels.

Imagine for a moment that batteries with decent shelf lives are free.

You build a power plant on a geothermal vent in Iceland. The electricity it produces is plentiful and cheap. You run it full tilt charging batteries.

You ship those batteries to wherever you need cheap power, and send them back empty. This works with hydro, wind, solar, ...

Batteries do drive down energy costs because even ignoring transmission lines, they let you move energy in both space and time, pushing all energy costs towards the cost of the cheapest means of generation on its best day.

Re: Why is everyone trying to build a solid-state battery?

#126

Post by epistasis » Thu, Jul 30, 2026, 5:11 PM UTC

iso1631 wrote: post #120

epistasis wrote: post #76

Earlier quoted context omitted.

Storing a month of energy use doesn't make any sense when it comes to renewable grids. Since you don't have to mine/extract and transport an inventory, far far less storage is required.

Which just emphasises the point -- density and thus land use isn't really a major concern You could store an entire years worth of energy (not just electricity) for a fairly dense country like the UK and still have 95% of the country left for other usage.

Definitely! However I frequently encounter people on energy discussion forums that assume that we need 2-3 months of battery storage, perhaps because they see natural gas or other storage and assume that batteries need exactly the same thing, so I'm perhaps overly eager to respond to claims about month-long battery storage.

I had previously been hopeful that battery storage would allow more shared used of land, but the fire risks of batteries have been pretty severe. And since the land usage requirements are fairly low, there's no need to enhance the risk by putting batteries, say, in enclosed spaces of former natural gas generation facilities [1].

I'm hopeful that we'll see a lot more storage, say a shipping container's worth, at the end of distribution feeders, which helps suck up residential solar with minimal resources, but solving the problem of "who pays for the benefits for all" when the utility is incentivized to keep grid costs high means that nobody is knocking down doors to make that happen...

[1] https://www.utilitydive.com/news/moss-landing-fire-battery-s...

Re: Why is everyone trying to build a solid-state battery?

#127

Post by bawolff » Thu, Jul 30, 2026, 5:11 PM UTC

thelastgallon wrote: post #97

iso1631 wrote: post #47

Earlier quoted context omitted.

Not all batteries need to be mobile. A 1 GWh grid scale battery takes up about 4 hectares at the moment. The UKs total energy use is about 2,000GWh a day. It would need to use 240,000 hectares to store all energy requirements (eletric, transport, heating etc) for a whole month. Even in extreme cold conditions it would last a couple of weeks. That would be about 1% of land use.

Instead of batteries, why not green hydrogen or green ammonia? Ammonia is needed for fertilizer, storage/logistics are a solved problem. Emergency plants around that can use ammonia as fuel can solve the dunkelflaute problem? Another option is natural gas peaker plant on a ship/barge. Have a fleet of these around that can dock at any port and supply electrictity. A peaker powership is essentially a mobile, marine-cla…

> Another option is natural gas peaker plant on a ship/barge. Have a fleet of these around that can dock at any port and supply electrictity. A peaker powership is essentially a mobile, marine-class version of an onshore peaking power plant.

Why would you want this?

Re: Why is everyone trying to build a solid-state battery?

#128

Post by spockz » Thu, Jul 30, 2026, 5:13 PM UTC

kansface wrote: post #100

raumgeist wrote: post #26

Earlier quoted context omitted.

I think, apart from finding better Batteries altoghether, we should build multi-tier batteries inspired by biology. Humans have bloodsugar, sugar in the Liver and then fat. All of them have their respective properties with availability and amount. This way, engineering tradeoffs could be allocated much more fine grained. For example, a while ago I read about a startup building an energy storage where they heat up lar…

I look to a future of regularly servicing the immune system of my battery.

That reminds me of the gel packs in the USS Voyager. At some point they became “infected” and they needed to the raise their temperatures to let them destroy the infection!

Re: Why is everyone trying to build a solid-state battery?

#129

Post by not_the_fda » Thu, Jul 30, 2026, 5:16 PM UTC

heaney-555 wrote: post #115

zuzululu wrote: post #112

Earlier quoted context omitted.

uphills + cold/hot climates, the ranges won't be able to compete with ICE. its basic physics. cold uphill still reduces charging speed, available power, and range, while sustained heat accelerates degradation. Thermal-management systems mitigate those weaknesses by consuming energy and adding cost, weight, and complexity. meanwhile ICE has gotten ridiculously clean and efficient over the years it is more efficient at…

The latest battery chemistries perform incredibly well in cold and hot climates. Internal combustion is not clean, and is inherently significantly less efficient than an electric motor. Also, LFP chemistries are incredibly safe compared to NMC, which is what you're concerned about in terms of thermal runaway. ICE is mostly stagnant tech. Meanwhile EV tech is rapidly improving!

> The latest battery chemistries perform incredibly well in cold and hot climates.

Depends on your definition of cold. California cold sure. Wisconsin cold you are looking at losing 40%-60% range.

Re: Why is everyone trying to build a solid-state battery?

#130

Post by ux266478 » Thu, Jul 30, 2026, 5:17 PM UTC

saltcured wrote: post #79

csours wrote: post #68

Earlier quoted context omitted.

It's an interesting discussion, because if you assume access to atmospheric oxygen, gasoline is MUCH more energy dense. TNT.....: 4 kJ/gram and 7 MJ/liter Gasoline: 43 kJ/gram and 33 MJ/liter

The previous point is fair though. What is the energy density of gasoline in a stoichiometric mixture with its oxidizer and not already detonated? That's where TNT beats it by a long shot. The mixture with any chance of being stored would be some relatively low pressure gas. Edit: Or, a fair closed-system comparison to a battery would need to include a liquid oxygen tank or similar so you have the two components stor…

In the context of the conversation, it doesn't actually refute the point though, which is that explosive danger is contingent on a much broader set of relations than simple energy density. Gasoline just demonstrates the disconnect. Tacking on additional conditions to make high-density batteries dangerous is exactly what the engineering goal should be.

As a stupid example, if we have a high density battery technology that never explodes unless, say, under magnetic forces only seen being produced by magnetars, that's a pretty safe battery.