Exploring Massless Energy Battery Breakthrough

I was watching this and thought now an extra battery in our flashlights. The traditional ones we use now and the body tube as a supplement. It’s not a replacement in electronics but an addition. https://www.youtube.com/watch?v=7rJf_n3bc0I

I’m glad some of BLFers watch some instructional videos. Well, Matt Farrell is informative and stays atop the buzz; but for what it’s worth, it’s a marketing ploy.
“Massless” meaning not added container weight. So how do we change the battery pack? Wouldn’t having a sealed battery in the flashlight be about the same? And imagine having the contents spill out on impact. Add some secondary container and you are back at square one.

So basically throwaway EVs.

There has been much ongoing hype about many new battery technologies. But finding a manufacturer to commit large amounts to gear up a plant and take the risk, not foreseeable. Of course, the automotive industry is trying hard to differentiate from among themselves, but I believe this leads to more consumer chaos as with the USB standard and Qualcomm’s QC3 vs type ‘C’ in-operationallity. And then you have every EV carmaker with their own charging system and plug (in USA)…

This is silly. He thinks that his claimed 4.5% will enable longer range EVs and get rid of cylindrical batteries.
He is off by several orders of magnitude.

Here is the analysis and modeling of this tech that I did at /r/batteries:

The actual paper: https://onlinelibrary.wiley.com/doi/10.1002/aesr.202000093

I’m not extremely convinced by the idea of structural batteries. Fundamentally they almost certainly must be a compromise. A structural element that doesn’t have to contain chemical reactions can be a better structural element. A battery that doesn’t have to be load bearing can be a better battery.

The battery has an energy density of 24 Wh/kg, meaning approximately 20 percent capacity compared to comparable lithium-ion batteries currently available. …. with a stiffness of 25 GPa, the structural battery can really compete with many other commonly used construction materials.

It is better than wood or plastic but not with materials commonly used on cars.

  • aluminum: 67 GPa

  • steel: 200 GPa

  • carbon fiber: 181 GPa

(Though specific stiffness seems more useful than youngs modulus.)

The future stuff is more promising:

such a battery could reach an energy density of 75 Wh/kg and a stiffness of 75 GPa. This would make the battery about as strong as aluminium, but with a comparatively much lower weight.

But that battery would still be 40% lower capacity. And this assumes that the common li-ion tech makes no advances in the future.

The “massless” claim seems to be a stretch that heavily depends on these future advances. The battery on a BEV already weighs more than the frame so there is going to have to be some extra mass. Numbers from Tesla Model S Weight Distribution

  • battery: 28%
  • frame: 17%
  • motor: 23%
  • everything else: 32%

From this we can make a system of linear equations where by we can predict what needs to happen to maintain the range and acceleration. (Lighter cars can use smaller everything for the same performance.) Let’s solve for the end-game. Fully structural battery that is “massless” because it perfectly matches the frame. How good is it with this new tech? And how good does it have to be in terms of Wh/kg to match today’s EVs?

  • range = battery / weight

  • acceleration = motor / weight

  • strength = frame / weight

  • weight = battery + frame + motor + 0.32

The frame would need to be heavier to match the strength. And we’ll remove the entire weight of the batteries. That lets the frame and motor both decrease in size. Using this new structural battery in a “massless” configuration results in the following car:

  • structural battery: 34% mass

  • motor: 23% mass

  • misc: 43% mass (held constant but is a higher % because total mass is lower)

  • total mass: 26% lighter

  • acceleration: same

  • strength: same

  • range: 76% lower

Using their future-tech numbers (75 Wh/kg and 75 GPa) gives us the following car:

  • structural battery: 15% mass

  • motor: 23% mass

  • misc: 62% mass (held constant but is a higher % because total mass is lower)

  • total mass: 48% lighter

  • acceleration: same

  • strength: same

  • range: 67% lower

Now obviously this range could be improved. Use a bigger structural battery. However then the frame is unnecessarily strong. It would be more cost effective to extend range by adding a non-structural battery pack instead of making the frame be 2x beefier. (But that isn’t “massless” any more.) Keep in mind that I am not saying that structural batteries are useless. Just that the claim of “massless” doesn’t hold up unless you are willing to throw away most of your range. (However structural batteries could be useless if they are not price competitive with a simple frame and simple batteries….)

For a structural battery to actually be massless it would need to have the strength of aluminum and an energy density of 200 Wh/kg or 70% better than current li-ion batteries.

Going to have to watch more than the 1st minute. The claim is the weight of the structural material along with the weight of the batteries work against the range. By using a carbon fiber layered with other components to act as a frame/power supply. Getting two items with the weight cost of one. In the example of the electric plane they claimed that this material would give the needed structural strength while supplying 4.5% of its energy. In the case of the Tesla they clearly showed that the batteries are still used but also encased inside of a structural carbon material that also happens to store some electricity. This removes weight kept the batteries and added a small amount of extra electrical capacity. Clearly showed that this was not a replacement of batteries but a supplement via the structure in the case of cars, cellphones, etc.

Now for flashlight most use a battery tube to hold the cells and act as a conductor between the tail and head. Picture that tube holding some charge to supplement the battery or run the light in a much diminished capacity. Like staying on while you change batteries.

Much analysis. If they want to go forward with such, battery tech has to improve. We’re seeing gradual steps and that may make it to 200Wh/kg, but that would be much further later than the present.

But it doesn’t address the non-replaceable issue. As for flashlights, I like my lights to have battery options, as the tech sometimes evolves just in line with the emitter’s demands.

Wasn’t Elon promoting the idea? Not that I want to knock him down for forward-thinking, but he’s known for conjuring things that don’t always play out. He does get the ball rolling, which is much more than other car makers.

And he’s got an engineering team. They may say ‘nay’ or ‘yah’.

edit:
Never understood this as an ‘added’ energy storage. As with planes (and Tesla), I thought the structural element is composed of the battery pack.

Interesting video texas shooter… thanks for sharing. :white_check_mark:

I guess time will tell where this goes.

I watched the entire video.
Its a nice idea but the energy density is too low.

If want to be mean i could talk about how he glossed over the collision/damage risk, how his complaining about adding more batteries cutting range while technically correct is not a big deal (doubling the capacity does not cut range by even close to half for example, you would lose a fairly low percent), his Tesla patent mention has little to do with the problem at hand and that the real impediment to EV adoption is not range (Tesla has range assurance and EV chargers are a dime a dozen compared to a gas station) but that battery prices are still too high. At $50/kWh which is expected to happen an EV would cost less in purchase price compared to a gasoline/diesel vehicle. Thats when the magic happens.

Lets look at 20Wh/kg
A 150g flashlight (a bit more than a Convoy M1) would hold 3Wh of energy. That is less than 1/4 of a 3500mAh 18650. Or about 16% of a 5000mAh 21700. Also being carbon fiber it would probably cut the weight of the flashlight in half if not more cutting the energy held by a commensurate amount.

I re-watched the video with a critical eye and the very mention of using both types of technologies – Chalmer’s carbon fibre and Tesla’s integrated battery pack (at 3:11).

There are two concepts here. At the very start (1:06), Matt states “the is no separate battery pack when the structure itself is the battery pack”. But then he adds the Chalmer’s battery as an added energy storage to the Tesla’s integrated battery pack (6:22). To which he states “a viable option” (6:52).
Conjecture of his doing.
Using the Electra plane as a model, there was a 1.5% weight savings (which he extrapolates as 4.5% being the plane’s energy storage is 1/3 total weight).

I stand corrected as I had skimmed the video (had seen the night before and must have dozed off).

I doubt the cost-effectiveness of integrated battery pack along with Chalmer’s carbon structured batteries would make this a viable option. Perhaps in mainstream integrated energy storage for aerospace and aviation where weight is empirical to performance.

And I still believe structural batteries, Tesla’s, as throwaways, not a good feature for cars. The Chalmer’s carbon fibre battery, as Parametrek stated, is a compromise against the strength of materials versus the chemical storage capacity.

I agree this may be niche construction. Wings, limited fuselage on a special run plane combining structural, battery, solar cells. With the addition of other batteries. Price is the concern, if cheap enough it could be the roofs of future building. Structural carbon fiber, battery, bonded with solar cells. As sections, replaced as needed. It’s in its infancy but may pair very well with solid state battery research.

massless battery is dumb

very hard to replace battery

any minor crash might damage part of the ‘battery’

frame will now have to be stronger, adding to weight

car must be designed around battery - suboptimal

hard to isolate passengers from battery fires or danger

There may be something here for some applications. For a vehicle it could be more than just frames. As he mentioned fenders, other body panels etc. I think it’s a long ways off and they haven’t simply added salt to spice and see the reaction, hint, corrosion. Again possible applications not necessarily just frames. Just add fusible links, quick disconnects, and other protections and maybe there’s something here 10 years out.

That’s exactly what I was thinking. You could have a literal “powerwall”.

Unless someone drives a car into it, drills holes into it to run cables or mount a dish-antenna, etc.

Oh god, drilling holes in it could electrocute the driller or lead to an explosion or fire :person_facepalming:

Wellp, that’d be a good lesson!

They could be built with safe zones for mounting, attachments, drilling or whatever. Or go all pie in the sky. Get 3M involved in the design and they can make it self-healing for nail holes, bullet holes for Chicago, cracks of all sizes in earthquake zones, etc.

Given how this is relatively low energy density not to worried about drilling a hole through it. Should be lower reactions the the relatively safe LiFePO4. Even at current solar cell tech if you destroy a cell the series shuts off not the whole panel.