When the H2 fuel is pressurized, the fuel cell system gets over 2 kilowatt
per kilogram.


Hydrogen fuel cells are a fantastic way to generate electricity from energy dense hydrogen, that can be produces using renewable energy. This means they are a great option for low carbon transportation, especially as the
distances get longer! However, aviation has always been a challenge. Thankfully, ZeroAvia have been working on an amazing new technology: turbo charged air cooled high-temperature pem fuel cells. These have much higher power densities and therefore enable long distance hydrogen electric flight.
I went to their labs to check it out!

Check out ZeroAvia here:
https://zeroavia.com/
With up to 60 times greater specific energy and lower cycling costs than lithium-ion batteries and numerous advantages over all other decarbonisation solutions, hydrogen-electric powertrains are the only viable, scalable
solution for zero-emission aviation.

Data Sheets: https://zeroavia.com/in-house-tech/

-----------------------------------------------------------------------
Video: https://youtu.be/BPafpvm1g3w

0:00
[Music]
0:00
this video explores a new hydrogen
0:02
technology that will deliver over four
0:05
times the power density of the fuel
0:07
cells currently in cars and I've been
0:10
granted special access to go and see
0:12
them in person hi I'm Val toov founder
0:15
in CEO Zer AIA we're here in our
0:18
location in Sandwich K where we have
0:20
high temperature fuel cell technology
0:22
development zero emission Aviation is
0:25
often seen as the final frontier of
0:27
clean transportation and now zero avas
0:30
new hydrogen fuel cells could unlock
0:32
flights some people thought would be
0:34
impossible at zero AIA we're working on
0:37
the next generation of power plants or
0:39
engine replacements for commercial
0:

Aviation so we're targeting larger
0:42
aircraft going longer distances for that
0:45
type of aircraft um which is the
0:47
majority vast majority of the emissions
0:50
from Aviation what's important is high
0:52
energy density and high specific
0:55
energy amount of energy that you can put
0:57
on the aircraft and the amount of power
0:59
that you can generate per unit of mass
1:01
and volume and that's where we believe
1:04
hydrogen is the only answer and hydrogen
1:07
electric specifically or hydrogen fuel
1:09
cell based power plants are the right
1:11
answer Time Magazine has named Zero Avia
1:14
the number one green tech company of
1:17
2024 part of this title comes from their
1:19
breakthrough development of
1:21
turbocharging high temperature hydrogen
1:23
fuel cells so how do high temperature
1:26
fuel cells work and why are they so much
1:28
more power dense
1:30
in January 2023 zero Avia flew the
1:33
world's biggest hydrogen electric
1:36
aircraft using a more standard low
1:38
temperature fuel cell in its powertrain
1:41
Regional airlines are placing orders for
1:43
their hydrogen Electric engines but for
1:45
zero Avia these are just steps towards
1:48
powering bigger planes that emit only
1:50
water vapor and heat to understand zero
1:54
avia's high temperature fuel cell is
1:55
probably useful to look at the
1:57
technology they're building on and
1:59
disrupting the most popular fuel cells
PEM Fuel Cell
2:02
use a proton exchange membrane or pem to
2:06
induce the chemical reaction that
2:08
generates electricity pem fuel cells
2:10
were developed by General Electric
2:12
researchers in the 1960s and used for
2:15
NASA's Gemini space program there are
2:18
three critical components to the fuel
2:20
cell and they're stacked up in layers
2:22
the bipolar plates on either side hold
2:24
the whole stack together and Marshal the
2:27
flow of molecules the gas diffusion
2:29
layers usually carbon cloth or carbon
2:31
paper act like crowd control making sure
2:35
everything flows evenly into the main
2:37
Arena together with the catalysts and
2:39
membrane these make up the membrane
2:42
electrode assembly or mea hydrogen gas
2:46
and oxygen from the air arrive at
2:48
separate entrances hydrogen is split
2:51
into protons and electrons via a
2:53
catalyst layer usually Platinum the
2:56
proton exchange membrane allows the
2:58
protons through to the cathode but the
3:00
electrons can't gain entry instead
3:04
they're pushed through an electrical
3:06
circuit creating electricity before
3:08
reaching the cathode where they rejoin
3:10
the protons and oxygen to form water the
3:14
only other byproduct is heat so the
Heat
3:17
three critical components of the whole
3:18
operation are the bipolar plates gas
3:21
diffusion layers and membrane electrode
3:23
assembly or mea as I mentioned before
3:26
most fuel cells run at low temperatures
3:29
they're known as LT pens and power cars
3:32
like the Toyota marai and new Honda CRV
3:36
low operating temperatures between 65
3:38
and 90░ C make these systems reliable
3:41
and durable but keeping them at the
3:44
right temperature requires significant
3:46
effort from heavy water cooling systems
3:49
known as part of the balance of plant
3:51
components not great for planes this is
Cooling
3:55
where zero Avia saw an opportunity so hi
3:58
I'm Rudolph head of R&V zero Ava the
4:00
high temperature fuel cells operate at a
4:02
higher temperature but also for our
4:04
specific implementation and our novel
4:07
implementation of it we use direct air
4:09
cooling which then of course saves a lot
4:12
of the balance of plant components in
4:14
terms of we don't need additional heat
4:17
exchangers and we don't need additional
4:19
coolant pumps and you save all the the
4:21
coolant fluid that you that you would
4:22
have in the typical low temperature leid
4:25
cooled P fuel cell stack system this
4:29
seemingly simp simple change from low
4:30
temperature to high temperature is what
4:32
allows the air cooling system to work
4:35
because although air cooling isn't as
4:37
effective as liquid cooling the hotter
4:39
the fuel cell is the easier it is to
4:42
cool this is because hot things want to
4:44
cool down quicker than cold things as
4:47
well as reducing the need for complex
4:49
water cooling systems one of the genius
4:51
ways zero Avia system uses the extra
4:54
heat and pressure is for turbocharging
4:57
similar to in a car Power TR consist of
Turbocharging
5:00
two main parts it's a power generation
5:02
part and the fuel tank with the fuel so
5:06
you should care about weight of both and
5:08
volume of both and uh efficiency
5:11
efficiency allow you to minimize
5:13
hydrogen consumption and reduce your
5:15
tank weight and tank volume to address
5:17
this challenge we developed uh two bar
5:19
po fuel cell system which uh combines
5:22
first in the world combines
5:24
turbocharging of fuel cells and air
5:26
Cooling and this allow us to maximize
5:28
power output
5:30
uh of the fuel cell system and uh to get
5:34
or to get over 2 kilowatt per kilogram
5:36
for the system level and minimize weight
5:39
therefore minimize weight of the system
5:41
when you operate at high altitude you
5:43
have to compress air four five times uh
5:46
some for high altitudes even more and
5:48
that's a huge power you need you have to
5:51
spend for compression and uh this uh
5:54
affects on your efficiency if you do not
5:56
care how how to recover uh this power
6:00
all G gases including reactant gases
6:02
passing through the system increases
6:04
temperature expands and uh uh can
6:07
provide more mechanical Power on an
6:10
expander on an expander and uh that's
6:12
the way we uh recover power uh and to
6:16
return this power to the system that's
6:19
uh one of the key Point whereas a lot of
6:21
low temperature systems like on the
6:23
Toyota marai use an electric compressor
6:25
to increase the pressure and therefore
6:27
oxygen density of the Inc air a turbo is
6:31
much more efficient this is because it
6:33
uses energy that would otherwise be lost
6:36
in the exhaust to spin a turbine which
6:39
then in turn spins a compressor that it
6:42
is mechanically linked to the output of
6:44
this compressor is oxygen dense air that
6:47
can then be FedEd into the fuse cell we
6:49
have a lot of uh extra heat and uh there
6:52
are a lot of uh ideas and options how to
6:55
use this heat for example anti-icing uh
6:57
procedures with htpm you had of a lot of
7:00
benefits and opportunities how how to
7:03
use this heat for for aircrafts we at
7:05
the beginning of our way and I believe
7:08
we will find a lot of brilliant ideas
7:10
how to use this heat and uh but the main
7:13
idea right now is to get light with and
7:16
extremely efficient power Trin power
7:18
system for for aircrafts and we are
7:21
going to have it in in the coming years
7:23
after hearing this I couldn't help but
7:25
think why isn't everyone else doing this
7:27
but as it turns out when you go to high
7:29
temperature
7:30
things get a lot more complicated so the
7:32
team took me on a tour to show me these
7:34
challenges and their innovative
7:36
solutions now the complex projects these
7:39
scientists and engineers at Zer AV are
7:41
working on may seem daunting but with
7:44
the right tools anyone can start
7:46
learning stem subjects which is why
7:48
before this tour I have to tell you
7:49
about brilliant who is supporting this
7:51
video and made it all possible brilliant
7:53
lets you learn by doing and is the best
7:56
way to help reach your goals for
7:57
understanding maths science and
7:59
engineering at your own pace they have
8:02
thousands of lessons from the basics up
8:04
to Advanced levels and they helped me
8:06
during my studies to start understanding
8:08
so many new topics the lessons are
8:11
seriously fun to do and can be done in
8:13
bite-sized sections to fit around your
8:15
busy schedule whether you're a
8:16
professional student or just lifelong
8:19
learner I've always struggled with
8:20
chemistry which can make fuel cells
8:22
pretty difficult to understand at first
8:25
however Brilliance courses make any
8:27
topic from chemistry to physics
8:30
approachable for anyone there are also
8:32
courses with fantastic real world
8:34
examples like getting handson with a
8:37
large language model similar to the one
8:39
behind chat GPT whether it's for career
8:41
progression or your own curiosity you're
8:43
definitely going to love brilliant so
8:45
use my Link at brilliant.org zeroth to
8:48
get started free for 30 days okay now
Inside Layers
8:52
let's look at the inside layers of this
8:53
fuel cell and how they made this
8:55
breakthrough possible first let's see
8:58
how they've made incredibly lightweight
9:00
aluminium robust enough for the
9:02
corrosive environment of the fuel
9:05
cell i ball blade and which is very good
9:11
in thermal conductivity which is really
9:13
good in rejection of the heat produced
9:15
by the operation of the fuel cell uh
9:18
what is the challenge here that uh
9:20
technology operates with a phosphoric
9:23
acid as electrolyte and at the elevated
9:26
temperature up to 200░ C and in this
9:30
condition aluminum cannot SVP as a metal
9:32
so it will dissolve and uh so that was a
9:36
first technology we as r& the functions
9:38
supported to develop the special
9:40
protective and same time conductive
9:42
pting but this is just the aliminum
9:45
bipol plate as we get it from our vender
9:48
from our supplier and uh this is uh
9:51
really really light what we do what we
9:53
do here actually in this particular room
9:56
uh that we why the our first l or the
9:59
metallic lay this is a multi comp
10:02
multi-element uh coating several metal
10:04
elements and inorganic elements uh and
10:08
uh the function of this coating to
10:10
provide the
10:11
conductivity and to uh reduce the
10:14
surface resistivity of this uh plate but
10:18
same time to protect and to to introduce
10:21
some Corrosion Protection this is the
10:23
bare aluminum this is already with the
10:25
first coing layer and why is it got this
10:28
dimple okay this is the flow field so
10:31
that's that's where the reacting gases
10:35
uh kind of diffuse and getting
10:37
distributed over the surface of the
10:39
bipolar plate because flow field kind of
10:42
enables the very good diffusion and
10:45
penetration of the gases through the
10:47
whole surface of the active area because
10:49
that's the area where the reaction
10:51
happens uh this surface this particular
10:54
surface needs to be very very conductive
10:56
so that pick up these electrons and to
10:58
convey discharge to the to the uh kind
11:02
of uh current current connector here of
11:05
the bipolar BL see you take the aluminum
11:08
bipolar play and that goes into one of
11:10
these tanks and yeah it actually goes to
11:13
the different tanks and on each tank
11:15
there is some proces where happens with
11:17
the surface of this uh uh b b blade uh
11:21
and finally yeah the final tank is just
11:23
wash out all the chemicals on the
11:25
surface and then it's drying on the oven
11:28
in the oven with that I would like just
11:30
to mention that actually this not just
11:33
uh the the final look of the of the
11:35
bipolar plate uh to make it ready to go
11:38
to the stack we uh p with with a second
11:41
layer and this is a uh polymer composite
11:44
layer and actually this second layer
11:47
also about 5 10 microns but uh it
11:50
generated the major contribution to the
11:53
corrosion protction of the the B of
11:55
Blade the key purpose of all of these
11:57
Coatings is it primarily corrosion prot
12:00
and combativity yeah uh actually if you
12:04
if you take just the aluminum and you go
12:07
to the f c yeah it will survive there
12:09
for I don't know uh several minutes 10
12:13
minutes Etc but it will work uh not so
12:19
efficient as for example this PL with a
12:22
cting so those are the bipolar plates
Bookends
12:25
the incredible bookends that sandwich
12:27
the other layers together Marshall the
12:28
molecu fuels and conduct electricity
12:31
with zero avia's proprietary coating
12:34
they have for the first time enabled
12:36
aluminium to survive the harsh
12:38
conditions in a high temperature fuel
Membrane electrode assembly
12:40
cell next up I met chief engineer Ronda
12:43
Stout she showed me the main Arena of
12:45
the fuel cell concert the membrane
12:48
electrode assembly we have the ability
12:51
to make our own um high temperature meas
12:54
and what the mea consists of is cathode
12:58
electrode
12:59
and an anode electrode and then we put a
13:02
piece of membrane in between and it's
13:05
really just making a
13:07
sandwich and then we put this into our
13:09
hat press it's a toasty machine
13:12
basically a hat yeah like a a hat
13:15
sandwich what would come out would be
13:18
you know an assembled mea that looks
13:21
like this what does me stand for a
13:23
membrane electrode assembly and then to
13:26
operate it we put it between the flow
13:28
Fields so on one side we have our
13:30
hydrogen flowing and on the other side
13:33
is the air and that's how we um create
13:37
the electricity is this a testing device
13:39
to make sure what that previous process
13:41
we've done here is working right and we
13:44
are developing um new catalysts so that
13:48
we can improve the performance um and
13:52
make the mea better for Aviation
13:56
Aviation applications so then in this
13:59
little baby goes over into the test area
14:03
so we can evaluate on how well it
14:06
performs the electrodes Ronda showed me
Catalyst
14:09
are made of a carbon cloth and have a
14:11
catalyst that is turned into an ink and
14:13
printed onto it the catalyst is an
14:16
essential part that splits the hydrogen
14:18
into protons and electrons since their
14:21
invention in the 1830s Platinum has been
14:23
used as a catalyst in fuel cells but
14:26
entire rods were used which turn out to
Catalyst Coating
14:29
be a pretty inefficient way of using a
14:31
precious metal Catalyst team lead Dr
14:34
Aron chander Asen showed me a bit more
14:37
about the Catalyst
14:39
coating
14:41
uh so I'm not sure you can
14:45
see uh it's a platinum carbon Catalyst
14:49
yeah so uh you can't see Platinum the
14:52
reason we couldn't see Platinum here is
14:54
because it's mixed in with carbon known
14:56
as the supporting material to make the
14:59
the Catalyst more efficient and
15:01
economical is this your is this your my
15:06
exper why this uh measurement is this uh
15:11
particular measurement will give precise
15:15
Catalyst information so it's quicker
15:18
more accurate and then once you find
15:19
something that looks promising you can
15:21
make sure it works with everyone else's
Electro Development
15:22
yes and finally the electro development
15:25
for the mea led by Dr Emerald Taylor she
15:28
talked to me through how they sped up
15:30
the reactions on the oxygen side of the
15:31
fuel cell to increase efficiency that
15:34
reaction is much slower can be a bit
15:36
clunky it's a bit like when you wake up
15:38
on a Sunday morning and you just don't
15:39
want to get out of bed right and we have
15:43
to work smartly to really get it going
15:47
running and working as hard as the
15:48
hydrogen oxidation reaction right we
15:50
also have to deal with the generation of
15:52
water there water is our V product so we
15:54
have gas coming in we have water VAP
15:56
coming out and we need to manage all of
15:58
that so we need to be able to reject
16:00
that and repel that from the cathode so
16:02
we can run at high current densities
16:04
produce more power but also man all of
16:07
these different nuances of the cath it's
16:09
a very complicated little potion that
16:11
we're trying to make with the bipolar
Stacking
16:13
plates gas diffusion layers and membrane
16:15
electrc interfaces all in order it was
16:18
time to stack it up was to start with
16:20
the first pipo plate at the very end for
16:23
the for for the one let's say the
16:25
negative uh terminal and then you start
16:27
with the membrane Electro Sly and then
16:29
bu for the plate and they alternate them
16:31
and they stack up uh in series because
16:34
you B the fuel cell Stacks power also by
16:36
stacking all the cells in series so
16:38
you're trying to get a particular
16:40
voltage as well correct yes because the
16:42
uh the typical voltage for uh for a fuel
16:45
cell one Fuel Cell by itself at no load
16:48
is around about 1.2 volts or around
16:51
about 1.1 volt and as you draw more load
16:53
from it of course the voltage goes down
16:55
to around about 6.5 Vols this stacking
16:58
of cell is similar to putting batteries
17:00
in series to get a desired voltage from
17:03
the overall battery pack on the next
Assembly
17:05
part of my tour Dr Sergey panoff gave me
17:07
some extra details about the fuel cell
17:09
as it starts to take its final form
17:11
during the assembly of the stack the
17:13
quality is examined and the layers are
17:15
built into their stack carefully using
17:18
guided supports this naked stack is then
17:21
put into a casing for testing here you
17:24
can see the quarter stack in one four of
17:27
the stack and short stti
17:29
uh just to validate that that everything
17:32
goes well and everything work properly
17:34
we assemble first the short stick it's
17:37
consist of six cells is consist of 44
17:40
cells and we put this equipment on a
17:43
test station just to validate that our
17:46
design Works after all of this is
Testing
17:48
completed they go on to be tested and
17:50
validated to make sure everything works
17:53
as hoped as they vary parameters like
17:55
temperature and pressure and we want to
17:58
do it in as much of an isolated
18:01
condition so we're just evaluating how
18:04
the MBA the membran El form we also have
18:09
right
18:10
here oh wow a a single full size cell
18:16
being tested under the same conditions
18:19
where we can control the temperature
18:21
very well control the pressure very well
18:23
and evaluate the full size MAA the
Applications
18:27
complete stack is then into a test rig
18:30
that looks ready for a trip to Mars the
18:32
rig is designed for full Stacks but on
18:34
the day a small stack was being tested
18:36
for its specific power and it was also
18:39
being tested for durability zavia is
18:41
aiming to get 10,000 hours in a future
18:44
iteration of the system and although
18:46
airplanes are the obvious application
18:48
high temperature fuel cells could
18:50
definitely be used in other places when
18:53
you think about other applications where
18:55
large powers are required like for
18:57
example um trucks uh heavy duty
19:00
Machinery Marine uh ships and even in
19:03
trains those are applications where HTP
19:06
technology can definitely bring a very
19:09
big Advantage U because of the thermal
19:11
management advantages that you have and
19:14
then if you put on top of that the
19:16
especially for mobile applications the
19:18
lightweight type of fuel cell Stacks
19:20
that we are developing and overall
19:22
systems that we are creating will be
19:24
quite beneficial for a lot of
19:25
applications outside of Aviation of
19:27
course our Focus at the moment is um
19:30
Aviation and this is zero Aria's Mission
19:33
but those um could be other
19:35
opportunities that could become
19:36
available down Steam for us as well one
Challenges
19:38
big question beyond all of this
19:40
technology is how the production storage
19:42
and refueling of hydrogen would work in
19:45
practice zero Avia isn't just thinking
19:47
about the technology in their fuel cell
19:49
but on the entire chain from hydrogen
19:52
production through to its use to bzero
19:54
emissions they'd have to use green
19:56
hydrogen so they are making their own
19:59
and partnering with other providers
20:01
though this will become a much larger
20:03
project as more planes take to the Skies
20:05
of course uh there are challenges on
20:07
this uh path and if there were no
20:09
challenges they would have been done
20:10
already um and it hasn't been so there
20:13
are challenges but uh we believe that we
20:15
can solve them uh some of them include
20:18
regulatory environment for example right
20:20
it's new technology Aviation is a
20:22
regulatory heavy industry things take
20:25
time um but uh we've been working with a
20:28
regulat
20:29
in the US in the UK and in Continental
20:32
Europe for a number of years now uh we
20:34
have flown a number of prototypes so The
20:36
Regulators are very familiar with our
20:38
technology so we believe we can actually
20:40
push the first uh set of uh engines into
20:44
the Market within the next two years two
20:46
two and a half years so 2025 2026 some
20:49
regulations are also working in zero
20:51
avia's favor as they make traditionally
20:53
fueled flight more expensive and as
20:56
subsidies are given to cleaner
20:57
Alternatives using us renewable energy
20:59
gives operators significant cost
21:01
advantages changing commercial Aviation
21:04
over to hydrogen is a huge challenge but
21:06
with a step change in fuel cell
21:08
technology from turbocharged high
21:10
temperature fuel cells combined with
21:12
global efforts and funding there's
21:14
something seriously going on here of
21:17
course there are some who think this is
21:19
too big of a challenge then again the
21:21
same was said for solo flight across the
21:23
Atlantic and space travel if you've
21:26
enjoyed this video please subscribe it's
21:27
free and help support this channel a lot
21:30
to make videos like this possible I also
21:32
think you might like some of my other
21:33
videos like this one on a new type of
21:35
propeller and as always thanks for
21:41
watching



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