DONUT LAB Video #8 - More Energy & Less Weight?

Donut Lab test video number eight. How

much longer can I keep this up? I don't

not know, but apparently season one for

Donut Lab's Gen 1 battery is going to

get dragged out much more. Here's my

summary for the key claims they've made

and the test that they've shown us.

Energy density of 400 watt hours per

kilogram and long life were recently

called into question by a now former

employee of Nordic Nano. That's the

company tasked with the mass production

of the Donut Lab battery. Marko does not

address those allegations in this video

and given that this was an official

criminal complaint filed, I'm sure the

Donut lawyers told them don't not talk

about this. So, they did not. What they

did talk about is another application

for their batteries given their

tolerance for elevated temperature,

lightweight, not that we know the

weight, and fast charging, they offer

advantages in the popular two-wheel

electric scooter category. Before we get

into those details, shout-out to Paul

who in my video for Donut Lab's April

Fools video pointed out that the lady

who interrupts is a reference to Javier

Seldron Cool. I I know I botched that

name. He works at Santza Energy, which

is part of the Donut Lab battery origin

conspiracy theory. So, thank you for

giving that insight. Maybe in weeks or

months from now when more details are

revealed, this will all make sense.

Maybe or we're just getting trolled.

Back to the scooter battery, the

benchmark battery is from Yamaha, which

powers their Neos urban electric

e-scooter. We don't know the exact

chemistry, but it is lithium ion with a

liquid electrolyte. Volts times amps

equals watts, so it's nearly 1 kWh

battery. Yamaha makes scooters that use

either one or two of these removable

batteries. It weighs 7.9 kg, so we can

calculate the energy density at the pack

level. Donut apparently doesn't mind

shaming other batteries by disclosing

their weight. It calculates to 122 watt

hours per kilogram at the pack level. At

the cell number, that would be a higher

result because you're taking out the

housing, wiring, the weight of all the

other components from the calculation.

According to Yamaha, charging for that

swappable battery probably would be done

indoors. You remove the battery and plug

it in. Wall outlets are 220 to 240 volts

AC in the UK and in Europe. The charger

puts out 3 amps and that charges a pack

from 0 to 100% in 8 hours. There is no

DC fast charging option for these

swappable batteries and they are

air-cooled, not liquid-cooled. For this

video, Donut Lab took their own cells

and made an alternative swappable pack,

not a direct replacement, but something

that could be used in a similar way. At

this point in the video, I felt like

this is

This is

What? This is boring. But upon the

fourth viewing, there are some clues

here. To make the pack compatible,

they'd need to achieve about 50 volts.

They can achieve that by wiring in

series 14 of the solid-state batteries

we've been seeing over and over again

throughout this series. That would give

this a nominal capacity of 26 amp hours.

I know in the last video, Donut Lab said

they prefer to use maximum capacity and

voltage, but we have specs for nominal,

so that's what I'm going to use. In the

video, Ville said that the solution

would have 35% more energy storage and

yes, it would be 1.3 kWh. 50.4 volts

times 26 amp hours. You can clearly see

that size is smaller, too. They say they

they've achieved a 35% reduction in

size. That looks about right. That plus

the 35% higher energy storage means the

volumetric energy density at the pack

level is more than twice as good.

Volumetric energy density is not

something they bragged about at the

reveal of their solid-state battery, but

it's important, especially for bikes and

scooters. He also said that mass was

lower at the pack level, a 25%

reduction. So, that would take the

swappable battery pack down to about 6

kg. We have watt hours and we have mass

and therefore, we have gravimetric

energy density of 221 watt hours per

kilogram. Cool. That's an 81% increase

in energy density by weight over the

pack used by Yamaha. Most of that should

be attributed to the battery cells,

although there is also the possibility

that the pack case itself and the other

components are lighter in the prototype

they created. The Yamaha battery is

rated to maintain a high level of

performance for 1,000 cycles. For an

e-scooter with a swappable battery, that

sounds good enough. Donut Lab, as you

recall, claimed 100,000 cycles, 100

times more, but admittedly, that is an

estimate based on a limited amount of

testing. So, does this confirm the 400

watt hour per kilogram energy density

claimed at the cell level?

No, we can't make that jump, but it is

significantly better than the benchmark

e-scooter battery at the pack level. It

has more energy storage for longer

range, a lighter battery that makes it

easier to remove and replace from the

e-scooter. It's smaller, allowing for

easier packaging and a slimmer design.

Their proposed packaging would put thin

sheets of aluminum heat conductors in

between the individual cells. Those

would draw heat out to the sides of the

swappable pack where other heat sinks

would draw the heat away. Swappable

battery packs can be charged at home or

swapped for a full battery at a swapping

station. The Donut Lab design would

allow for the swapping station operator

to fast charge them if needed to meet

demand, getting the low state of charge

battery you just inserted ready for

someone else to take in minutes, not

hours. The Yamaha wall charger used with

their packs only puts out 3 amps. That's

why it takes 8 hours to go from 0 to

100% state of charge, 4 hours to go from

20 to 80%. Donut Lab showed their

battery peaking at 270 amps. That's 10 C

charging for their cell. 20 to 80% takes

under 5 and 1/2 minutes. This drives the

cell temperatures up to 82° C even with

those heat sinks, but we've seen their

cells survive those temperatures in

other tests. So, you could swap out the

battery pack in your e-scooter, put it

into a swap station and that machine

fast charges it so that it's ready for

the next rider in less than 10 minutes.

That's cool, but is it really critical?

I I don't think so. High-powered DC

charging makes the swap station more

expensive. Charging it just kind of fast

is probably good enough and it makes the

equipment less expensive. They end the

video talking about how this could

benefit last-mile delivery bikes. I'm

working on a video of the Honda Fastport

urban delivery vehicle that I got to

fart around on. In my opinion, the

smaller, lighter battery is really the

key selling point, not faster charging

for an e-scooter. And if we are to

believe all the claims, the improved

safety of solid-state batteries is

important. E-scooters with removable

batteries are frequently taken into

high-rise apartments in large cities.

Very convenient for recharging, but

there have been cases of crappy, cheap

batteries catching fire while AC

charging indoors and the results can be

devastating. Solid-state batteries are

inherently more safe. Sure, you can push

them harder and allow them to get

hotter, but just being safer is is great

enough. That's it for this episode with

Donut Lab. 35% more energy storage in

35% less space with 25% lower mass. That

sounds good, but you know, maybe not

alien technology.