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

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

#61

Post by rootusrootus » Thu, Jul 30, 2026, 2:53 PM UTC

toss1 wrote: post #54

laxisOp wrote: post #6

We need way more research on batteries. People cant ingine what is possible if we make battery 10x energy dense.

It should be relatively straightforward to imagine — we already have that in gasoline-powered internal combustion engines. The Watt-hours per kilogram of good Lithium Ion batteries is around 250-280 Wh/Kg; for Lithium Iron Phosphate it's about 180 Wh/kg, and for Sodium-Ion about 170 Wh/Kg. The raw energy in gasoline is about 12,300 Wh/Kg but automobile internal combustion engines get only about 20-30% efficiency yiel…

> With a 130Lb/60kg battery instead, and saving the weight of the ICE engine and fuel system, the overall car design could go much more lightweight, regaining a lot of performance and range, all while gaining the huge torque of electric motors.

I think you're underselling it, even. A typical like-for-like modern EV is only marginally heavier than the ICE equivalent. If we were able to drop the weight of the battery by a thousand pounds, cars would be lighter than they have been in decades while retaining all the modern safety and convenience features we've come to expect. And if density improved along with weight, we could make EVs with the same form factor as today but with over a thousand miles of range. Not that we need that, but it is just as a tiny example of how mind boggling the game change would be.

As it is I've only recently internalized the notion that the most powerful electric tools are battery powered (what can I say, I grew up when rechargeable batteries were NiCad and they basically sucked). And it will just get better and better as time goes on.

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

#62

Post by superxpro12 » Thu, Jul 30, 2026, 2:56 PM UTC

heaney-555 wrote: post #27

dzhiurgis wrote: post #16

Earlier quoted context omitted.

Tesla has been around for nearly 20 years. Model S (12 years) has gained 17% of range due to chemistry (rest is system efficiency and simply bigger battery).

Range is not a real issue for electric cars. Charging time is, though, and there are massive improvements happening for that right now.

Tell that to my polestar 2 pls. and then come back again in the winter when it drops another 30% due to the battery heater energizing

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

#63

Post by lukan » Thu, Jul 30, 2026, 2:56 PM UTC

mekdoonggi wrote: post #22

GlibMonkeyDeath wrote: post #18

The article gives the technical reasons that answer the headline question (e.g. potential for better energy density) I am surprised they didn't point out the literal "killer app" - military drones. Energy density is king for any airborne power source. And dendrite growth during charge/discharge cycling isn't as big a deal for that application (how many times would you need to charge a disposable weapon?)

If the thing is going to blow up anyway, does it need to be light? Wouldn't you rather have more cheaper drones?

The lighter the further range or more explosive payload.

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

#64

Post by [deleted] » Thu, Jul 30, 2026, 2:57 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.

[deleted]

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

#65

Post by bluGill » Thu, Jul 30, 2026, 2:58 PM UTC

jgilias wrote: post #29

zamadatix wrote: post #24

Earlier quoted context omitted.

Less weight (all else being equal) is the same thing as more battery for drones. I.e. better range, payload mass, and/or flight time. You probably want both cheap and poor performing as well as expensive and high performing available.

In current battle conditions isn’t the range primarily determined by the size of the fiber optic spool attached to the drone than battery capacity?

Maybe. Last I checked Ukraine preferred radio drones to fiber optic - the spool is heavy and a limitation in many ways (not all that I understand). Fiber optics are used only when you can't get something else to works. Advances in AI, radio relay systems, self-navigation, and anti electronic warfare are all things they are working on so they can use more drones without fiber. For longer ranges drones fiber is not an option and so they have no choice but use something else.

Where fiber optic is used though, that is the limit. That is a minority though.

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

#66

Post by duped » Thu, Jul 30, 2026, 3:02 PM UTC

thechao wrote: post #23

trollbridge wrote: post #14

Earlier quoted context omitted.

I can - it’s called a bomb. Some of the problems with batteries are heat dissipation (one of those problems that superconductors would mostly solve), fire safety, and end of life disposal. Higher energy density makes it even worse. A good place to start would be a BMS on individual cells that monitors them for general degradation, unexpected discharge, unexpected temperature changes, and can remove a failing cell fro…

Gasoline has 10x the energy (MJ/Kg) than TNT, but it's not a "bomb". Being a "bomb" is about energy release rate . A battery is still controlled by its chemistry.

Poorly stored gasoline can spontaneously combust, though. So more like a firebomb.

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

#67

Post by 100percentjake » Thu, Jul 30, 2026, 3:05 PM UTC

dzhiurgis wrote: post #16

epistasis wrote: post #11

Earlier quoted context omitted.

The past 20 years have made lithium ion 2-3x more dense, both because of some chemistry changes and because of better pack level design. And it's still improving at about 5% per year.

Tesla has been around for nearly 20 years. Model S (12 years) has gained 17% of range due to chemistry (rest is system efficiency and simply bigger battery).

BMW i3 went from 60Ah to 120Ah of battery capacity (and slightly more voltage) in the exact same chassis through the span of its life (2014-2022, RIP). It is even possible to put the later 120Ah batteries in the early 60Ah cars and reap the rewards, and is a practice that is actually supported by the cars' software natively.

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

#68

Post by csours » Thu, Jul 30, 2026, 3:06 PM UTC

vikramkr wrote: post #36

thechao wrote: post #23

Earlier quoted context omitted.

Gasoline has 10x the energy (MJ/Kg) than TNT, but it's not a "bomb". Being a "bomb" is about energy release rate . A battery is still controlled by its chemistry.

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…

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

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

#69

Post by tflinton » Thu, Jul 30, 2026, 3:09 PM UTC

clickety_clack wrote: post #17

laxisOp wrote: post #6

We need way more research on batteries. People cant ingine what is possible if we make battery 10x energy dense.

I think people can imagine lighter cars and laptops and things. Is there something bizarre that’s unlocked like battery powered space launches or something?

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 anywhere the world millions of lives would be saved. For example;

If energy is cheaper than the price of water you can pull water out of thin air (dehumidifiers).

If energy is cheaper you can grow food in areas you normally couldn't.

When you can transport anything for cheap you can move food to areas that are vulnerable to food insecurity.

If you can store energy at large scale you can nearly eliminate grid failures, savings lives in the summer and winter.

Costs for transporting food would go down significantly, imagine groceries being 10-15% cheaper.

Assuming airlines have competitive pressure you could expect plane flight costs to drop 20-30% improving everyone's mobility.

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

#70

Post by SoftTalker » Thu, Jul 30, 2026, 3:09 PM UTC

rootusrootus wrote: post #61

toss1 wrote: post #54

Earlier quoted context omitted.

It should be relatively straightforward to imagine — we already have that in gasoline-powered internal combustion engines. The Watt-hours per kilogram of good Lithium Ion batteries is around 250-280 Wh/Kg; for Lithium Iron Phosphate it's about 180 Wh/kg, and for Sodium-Ion about 170 Wh/Kg. The raw energy in gasoline is about 12,300 Wh/Kg but automobile internal combustion engines get only about 20-30% efficiency yiel…

> With a 130Lb/60kg battery instead, and saving the weight of the ICE engine and fuel system, the overall car design could go much more lightweight, regaining a lot of performance and range, all while gaining the huge torque of electric motors. I think you're underselling it, even. A typical like-for-like modern EV is only marginally heavier than the ICE equivalent. If we were able to drop the weight of the battery b…

Some people might need that range. If you cannot charge at home and you don't have good public charging infrastructure then you might want enough range so you only have to deal with charging once or twice a month.