Batteries with 50 per cent more energy with pure silicon anode • Hacker News Board

Re: Batteries with 50 per cent more energy with pure silicon anode

#31

Post by csours » Tue, Oct 31, 2017, 7:39 PM UTC

hwillis wrote: post #22

csours wrote: post #17

Earlier quoted context omitted.

What are the critical questions you should ask about battery technology? Here are some I've thought of, please suggest others: 1. Cost of raw materials - even if the tech improves, will it still be expensive? 2. Charge/Discharge cycle count - thermal and mechanical stresses 3. Power to weight ratio; power to cost ratio 4. Manufacturability - does it require novel manufacturing techniques or can it be integrated into…

It helps to have some level of understanding of the chemistry. It can be hard for anyone but a legitimate chemist to sniff out the bullshit in academic papers (I've fallen prey to this before; I'm just an electrical engineer). Raw materials can be important, but only very rarely and it can also be misleading. By far most of the cost comes from the complexity and time of manufacture. That makes it tricky. For instance…

Thanks!

Re: Batteries with 50 per cent more energy with pure silicon anode

#32

Post by praseodym » Tue, Oct 31, 2017, 7:49 PM UTC

Bud wrote: post #26

This article, and this comment thread, both seem to be ignoring what is actually in the way of any "50% more energy" battery tech being used in consumer laptops: FAA regulations limit all such batteries to 100 watt/hrs or less. It's not Apple, it's not Samsung...they have no choice. So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech i…

The 2017 15” MacBook Pro only has a 76 Wh battery, so this is mainly a design choice by Apple (smaller battery means smaller laptop) and not due to FAA regulations.

Source: https://www.apple.com/macbook-pro/specs/

Re: Batteries with 50 per cent more energy with pure silicon anode

#33

Post by jandrese » Tue, Oct 31, 2017, 7:55 PM UTC

hwillis wrote: post #18

jandrese wrote: post #13

Earlier quoted context omitted.

I have to admit I'm a bit concerned about the amount of cost savings that can be realized by building it with the same methods as solar cells . Even with the precipitous drop in solar cell prices over the past few years they still aren't cheap.

>Even with the precipitous drop in solar cell prices over the past few years they still aren't cheap. By what metric..? The amount of energy and power involved in the two uses is completely different. Do you happen to know the bulk cost of silicon, or how much silicon is used in solar cells, or how much of a solar cells cost it makes up, or what process is similar? You're not doing much more than a kind of free assoc…

The article states outright that they think they can make it to market quickly by leveraging Solar Cell production facilities.

The bulk cost of silicon is a moot point. That's like asking how Pizzas can be made more cheaply if you reduce the cost of the flour involved. It's the extreme precision ultra pure processing that makes it expensive, not the bulk materials.

Re: Batteries with 50 per cent more energy with pure silicon anode

#34

Post by woodandsteel » Tue, Oct 31, 2017, 8:05 PM UTC

hwillis wrote: post #10

Silicon has been used in batteries for several years now in low amounts. It hasn't seen larger use because it expands by 400% when filled, compared to graphite's ~12% expansion. Most attempts to solve this have been extremely complicated; nanopatterning, nanowires, graphene coatings to literally compress the silicon metal, etc. It's one of the most promising avenues for battery tech (silicon anodes alone may be able…

Could you explain what a pouch cell is? Is it the same as the battery in a cell phone or laptop? Why does it matter for this development that it's a pouch cell rather than some other type?

Re: Batteries with 50 per cent more energy with pure silicon anode

#35

Post by Ajedi32 » Tue, Oct 31, 2017, 8:06 PM UTC

praseodym wrote: post #32

Bud wrote: post #26

This article, and this comment thread, both seem to be ignoring what is actually in the way of any "50% more energy" battery tech being used in consumer laptops: FAA regulations limit all such batteries to 100 watt/hrs or less. It's not Apple, it's not Samsung...they have no choice. So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech i…

The 2017 15” MacBook Pro only has a 76 Wh battery, so this is mainly a design choice by Apple (smaller battery means smaller laptop) and not due to FAA regulations. Source: https://www.apple.com/macbook-pro/specs/

And that's a laptop. Watch and phone batteries store far less energy than that. Even the most power-hungry phone would certainly be able to take full advantage of a battery with an additional 50% capacity.

Re: Batteries with 50 per cent more energy with pure silicon anode

#36

Post by phinnaeus » Tue, Oct 31, 2017, 8:06 PM UTC

csours wrote: post #28

hwillis wrote: post #10

Silicon has been used in batteries for several years now in low amounts. It hasn't seen larger use because it expands by 400% when filled, compared to graphite's ~12% expansion. Most attempts to solve this have been extremely complicated; nanopatterning, nanowires, graphene coatings to literally compress the silicon metal, etc. It's one of the most promising avenues for battery tech (silicon anodes alone may be able…

> Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) What does this mean? I feel like I charge my phone more than 500-800 times.

Once a day for ~two years, and then the capacity is at 80% of original. Seems pretty accurate to me.

Re: Batteries with 50 per cent more energy with pure silicon anode

#37

Post by mitchty » Tue, Oct 31, 2017, 8:12 PM UTC

jpm_sd wrote: post #30

Bud wrote: post #26

This article, and this comment thread, both seem to be ignoring what is actually in the way of any "50% more energy" battery tech being used in consumer laptops: FAA regulations limit all such batteries to 100 watt/hrs or less. It's not Apple, it's not Samsung...they have no choice. So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech i…

Those rules have nothing to do with 9/11, they are based on risk of fire due to manufacturing defects.

That and limiting the amount of energy that could be released if there is a defect.

I don't think i'd want a 1Kwh battery on a plane.

Re: Batteries with 50 per cent more energy with pure silicon anode

#38

Post by mikeash » Tue, Oct 31, 2017, 8:15 PM UTC

hamandcheese wrote: post #20

hwillis wrote: post #12

Earlier quoted context omitted.

I assure you, they do regularly. A123 is the most well known example, but the vast majority of new developments don't involve a new company being formed. Making batteries is hard and few researchers want to build companies. Instead these developments quietly slip into commercial formulations as continuous, incremental improvements. There's certainly an unending flood of hyped up articles about new experiments, but al…

> Apple wouldn't even blink if a 50% better battery cost $60. Apple seems content to merely maintain the status quo of barely a days battery life. I would not expect them to lead the way on this front.

Apple loves to make their devices as thin and light as possible. That's why they maintain that status quo: they make their batteries only as big as they need to be to last a day. If this technology improved capacity by 50%, that means Apple could shrink their batteries by a third while still hitting that target, which they'd jump on.

(Personally I really wish they'd have a model with a much larger battery, because "lasts one day" really means "usually lasts one day but it depends on how you use it so you can't really count on it." But they won't.)

Re: Batteries with 50 per cent more energy with pure silicon anode

#39

Post by Johnny555 » Tue, Oct 31, 2017, 8:28 PM UTC

Bud wrote: post #26

This article, and this comment thread, both seem to be ignoring what is actually in the way of any "50% more energy" battery tech being used in consumer laptops: FAA regulations limit all such batteries to 100 watt/hrs or less. It's not Apple, it's not Samsung...they have no choice. So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech i…

I already get 6 - 8 hours of lifetime out of my laptop, I don't really need 50% more battery (saving a few ounces or cubic centimeters wouldn't make much difference to me either). I can use the power outlet on the plane if I'm on a flight longer than that.

However, I would love 50% more battery lifetime in my phone without adding more weight or volume.

Or 50% more range in an electric car (or reducing the size/weight/cost of the battery pack).

There are lots of applications for batteries that don't involve taking large batteries on the plane.

Re: Batteries with 50 per cent more energy with pure silicon anode

#40

Post by hwillis » Tue, Oct 31, 2017, 8:30 PM UTC

jandrese wrote: post #33

hwillis wrote: post #18

Earlier quoted context omitted.

>Even with the precipitous drop in solar cell prices over the past few years they still aren't cheap. By what metric..? The amount of energy and power involved in the two uses is completely different. Do you happen to know the bulk cost of silicon, or how much silicon is used in solar cells, or how much of a solar cells cost it makes up, or what process is similar? You're not doing much more than a kind of free assoc…

The article states outright that they think they can make it to market quickly by leveraging Solar Cell production facilities. The bulk cost of silicon is a moot point. That's like asking how Pizzas can be made more cheaply if you reduce the cost of the flour involved. It's the extreme precision ultra pure processing that makes it expensive, not the bulk materials.

> It's the extreme precision ultra pure processing that makes it expensive, not the bulk materials.

Batteries don't require 6N precision. Silicon anodes can be 99% pure and work fine. Metallurgical silicon is ~99.9%. Only the bottom shelf ferrosilicon stuff is My point is that you're making assertions that you don't fully understand. Why would batteries suddenly need extreme precision ultra pure processing? That doesn't make sense.

> It's the extreme precision ultra pure processing that makes it expensive, not the bulk materials.

That's my whole point. The expensive part is left behind because it doesn't have anything to do with batteries. The part that's left over is fancy sand and a mylar-making machine. The same machine used to make the very cheapest solar cells, the kinds in old calculators. The kind of machine that made the monitor you're reading this on. Not the 9N part.