one of the most crucial scientific breakthroughs over the next decade is most certainly going to
relate to energy storage with aging infrastructure increased weather severity increased penetration
of renewables and the ever-growing energy demand the world's problem solvers will need
to completely reimagine the grid we have covered so many different types of energy storage from
air and liquid metal batteries to mechanical energy storage today we're gonna look at one
of the most promising grid storage solutions that i've come across the flow battery and one
company particular that's taking an innovative approach to this very promising technology the
average battery is fully enclosed but what if we took all the chemicals out and stored in a tank
and pumped them through the actual cell what sort of pros and cons would we be looking at
i had the opportunity to meet with ess the iron flow battery company and we'll talk about
why i'm still bullish on their technology and approach on this deep dive here on two da vinci
special thanks to roborock for sponsoring this video check out my absolute favorite
robot vacuum cleaner the s7 plus link in the video description like we said up top we've covered lots
of different battery technology flow batteries share many similarities with other battery tech
out there but also have some key differences so in let's say a lithium ion battery you have your
anode your cathode a separator and an electrolyte which carries positive charge ions from anode to
the cathode or vice versa to this charge the anode releases lithium ions hence the name
to the cathode generating the movement of electrons to the other side during charging the
process is reversed with slow batteries the energy is actually stored in the electrolyte itself
so instead of a cathode and an anode you'd have a catholite and an analyte stored in liquid form in
two separate containers there are a few different types of flow batteries but the most common one
is called a redux flow battery here's how they work an energy source let's say a wind turbine
charges the battery by pumping electrons from the catholite the positive solution past the membrane
where they exchange ions inducing electric current with charge added or removed through
two electrodes a process called oxidation while it also pushes those electrons into the analyte
or negative solution a process called reduction so oxidation plus reduction redox energy gets stored
by increasing the potential difference between the two solutions in other words oxidizing one
and reducing the other energy capacity is purely a function of tank size the power is a function
of the anode surface area unlike a typical battery expanding on a flow battery could be as simple as
adding more analyte or catholic into the tanks to produce energy the process is reversed one of the
most common materials used for the electrolyte solution is vanadium the 20th most abundant
element in the earth's crust at a rate of 120 parts per million it's more abundant than nickel
at around 84 or lithium at 20. but compared to really common elements like aluminum at 82 000 ppm
and iron at 56 000 ppm vanadium is still not exactly easy to come by prices and supplies of
vanadium have stayed pretty stable but when we think about the scale of production we'll need
to truly add energy storage to our energy grid you have to start thinking about the resulting
strain on raw material supply chains lithium and lithium ion batteries are incredible they power
everything from our phones and computers to our cars and even we're starting to see them scaled
up for grid storage they're relatively cheap and very energy dense but when it comes to
grid storage there are some excellent reasons to look for other materials besides lithium
first and foremost we're going to need a lot of lithium to power things like electric
vehicles for example in fact while lithium certainly can and does work for grid storage
it really shines when energy density is crucial places like in cars and maybe one day in airplanes
there's also an issue of safety now we know the risk of lithium batteries is really minimal and
it tends to get blown way out of proportion by the media especially compared to combustion engines
which you know have a synonym for explosion right there in the name the lithium-ion batteries
do have some inherent dangers that need to be designed for well if the goal is safety
if energy density isn't that important as we can have these grid batteries be built outside of
town where there's plenty of space and land and material choice is of the paramount importance
then very few battery choices make as much sense as the iron flow battery let me explain why if
we're going to seriously scale up grid storage to allow sunshine to be stored for the evening
and to provide stability for the unpredictable nature of renewable energy sources
then we need to be thinking about huge battery installations iron is one of the
most important elements in our civilization and it is a very good thing that it is so abundant
luckily for me our sponsor this week is robo-rock and this
the roborock s7 plus smart vacuum and mopping robot with auto emptying dock the s7 plus
is ridiculously smart with lidar to scan your house and create maps of every room and hallway
then if there are areas you want to avoid like this area under my bed
just open the app and draw a no go zone with the auto empty dock you don't even have to remember
to clean the bin as it cleans itself for up to eight weeks when it returns to the dock to charge
the 2500 pascal suction power makes quick work of everything it counters big and small
on hard floors or carpet its 5200 amp battery is good for up to three hours of cleaning and over 2
000 square feet the s7 plus can even mop your hard floors it's smart enough to raise the mopping pad
over carpet and with a sonic vibration technology it scrubs your floors up to 3 000 times per minute
with my kids and dogs i schedule my s7 plus to vacuum daily and even do a mopping session in the
common areas when everyone's asleep each night so save time cleaning and support the show by getting
a robo rock s7 plus link in the video description ess was kind enough to give me a tour of their
headquarters in oregon where they are working on an iron flow battery while most flow batteries
have two separate tanks one for the catholic and one for the analyte ess design only has one tank
so what makes the ess iron flow battery special well the ingredients involved are simply water
salt and iron that's it there's no lithium there's no nickel no cobalt here's how the
charging discharge cycle works in the discharge state the electrolyte is made up of iron ions
fe 2 plus and supporting salts dissolved in water this mixture is the same for both the
positive and negative electrolytes during charge the fe2 plus ions in the negative electrolyte
combine with the electrons and plate onto the negative electrode as elemental iron
when fully charged the negative electrolyte has very little iron remaining in solution
and the positive electrolyte is mostly fe3 plus ions during discharge the reverse reaction
occurs so what's happening is actually a plating reaction where elemental iron is being plated to
the negative electrode which represents the charge state right so this is one of our 50 cell stacks
each cell runs an open circuit voltage around 1.1 volts because it's a flow battery
we don't connect them in series to get to the high voltage levels we actually pass that through
a dc-dc converter to boost the voltage from the stack voltage up to the dc voltage that
we want to connect into the systems at so that brings it from the stack voltage up to 850 volts
so the lithium system if they have a you know a half a volt lithium cell they just stack them up
in series to get up to a thousand or 1200 volts and that means that when they the voltage sags you
have that whole range drops down so it's operating over a huge dc voltage range because we're not
stacking them in series there is no sag at the high voltage level right that stays very stable
so this is all the mechanical equipment that's in the uh energy warehouse what you're seeing down
below is the main pumps to run the equipment and then above that is the electrolyte health system
so all of that equipment is really for cycling our electrolyte to maintain it and balance its
chemistry and so that that's something that's unique to flow batteries that we can run that
continuously even while we're operating the battery and keep about the electrolyte imbalance
and clean every battery off gases or has some type of side reaction during every charge cycle
same as ours in our case those side reactions uh ions are produced and our in our closed loop
system we created technology which is again a a big reservoir of our rp so it is uh how we can
process that continuously in a closed loop system so that the electrolyte is continuously refreshed
so at the beginning of every cycle the battery is essentially a brand new battery you see the
two looks like mini stacks up at the top yeah those are the kidneys that does that processing
what's equally exciting about this approach is how easily an iron flow battery can be scaled up
first you can increase the volume of the liquid tank or add more tanks and the salt and the iron
solution then you just need to add more cells increasing the capacity for iron plating to occur
so an ess flow battery could be started small and be added on to later much like a tesla power
wall or mega pack but unlike a lithium ion battery that has a life cycle of around a thousand cycles
or lithium iron phosphate chemistries that are closer to three thousand to 4 000 cycles
before losing about 20 of their capacity ess claims that their iron flow batteries can easily
last 20 000 cycles with minimal degradation and minimal cost plus in regards to safety
the iron salt solution is so safe if poured on top of a fire it would actually put the fire out
it's water-based battery so it's not gonna blow up in a fire not gonna start a fire it's a it's
a fire stopper not a fire starter in other words plus if any of the liquid ever leaked
it's not even hazardous to the environment we had one uh experience in the field where we had
damage to a system a system that we're deploying as a pilot back in 2017 and a couple of cups maybe
a quarter two of electrolyte uh spilled there was some cracks in the plumbing that happened
during transport you don't discover that until after you're putting fluid in and it's kind of
leaking out the actual remediation was dry it out power wash it that was the literal remediation for
that spill now that is truly a safe battery what about environmental friendliness and recyclability
the electrolyte itself is fully recyclable we could use it in another battery remember
it's just iron saturated salt water nothing's evaporating out nothing's leaving it you could
dry it out and take all the salts those salts are the same salts used in
winter de-icing operations they're the same salts used in wastewater treatment you could
take the dried salts you could landfill them uh and and dispose it it's it's it's the same
kind of materials you find in fertilizer the electrolyte at this facility if we wanted we
could literally put it down the drain we have to do two things before we do that one is we'd
have to neutralize the ph you know the operating ph of this about the same ph as a glass of wine
but we do have to neutralize it so neutralize it second is just filter it for solid so we're not
throwing chunks down the drain or putting the solids that would clog a drain
so if all this is sounding pretty good and you've seen our videos before you're probably asking okay
so what are the engineering tradeoffs one has to make when going with an iron flow battery
well first of all the battery is far less energy and power dense than lithium ion batteries
so you'll never see iron flow batteries powering the evs of the future but how important is energy
and power density for stationary storage so if you need to charge or discharge really quickly
it's still quite hard to beat the lithium ion battery the iron flow battery is far less energy
and power dense than the lithium-ion battery but the more interesting question is does it matter
unlike in a plane or a car the added need for weight or space isn't really a deal breaker
the stationary weight clearly isn't as much of a concern even for the larger footprint required
could be offset by placing these energy warehouses under massive solar arrays in my opinion using
very cheap and abundant elements for our future energy storage is by far the biggest key point
for instance consider the tesla hornsdale plant in south australia which is a 193 megawatt hour
battery plant if we used iron flow batteries for the plant instead sure it would take up more land
but it would save enough lithium ion batteries to build over 2400 80 kilowatt battery pack evs it's
hard to think about scarcity especially since the world has always seemed so vast and endless but
as we transition to building millions of electric vehicles everything we can do to alleviate supply
chain strains will be crucial so incredibly safe uses some of the most abundant materials on earth
very affordable and has long cycle lifetimes but it takes so much more space and weight
but that can't be it right i mean if the iron flow battery really was such a slam dunk
why hasn't anybody else sorted out yet well it turns out there are a few key challenges
that have until now not been solved so the two main challenges with the iron based chemistry
one is going to be around side reactions and the second one is going to be around
the proton imbalance and so as the battery is operating so your the battery's charging
there's basically a perfect reaction uh on the on the positive side every amp that goes in
goes to useful work on the negative side of the battery however every amp that goes in around
one percent of that is converted to hydrogen it's not useful um just because of the potential for
operating and you'll up you'll evolve hydrogen and so what happens is over time the positive state of
charge of the battery will get higher state of charge than the negative side and because you're
also evolving hydrogen you're also losing protons in the system which means the ph is going to rise
and during charge the ph is going to the protons they want to stream from the positive side
to the negative side and then they're going to evolve on the hydrogen and over time
the ph is going to rise and you could form those hydroxides on the positive side what
the proton pump does is essentially takes that hydrogen that was evolved and converts it back
into a proton on the positive side and when it does that it also brings a state of charge
in balance as well so the proton pump really keeps the battery in state of charge balance
and also in ph balance my name is julia saan i'm the co-founder and chief technology officer of ess
you know in terms of a flow battery to iron flow battery particularly i think one of the things
i like to highlight is that you know people are familiar with batteries you go to the
store you buy these batteries are coming as this battery packs right so essentially
what's inside the packs are chemicals and these chemicals are used to store energy
now the difference between a traditional battery that you can go to the store and buy and versus
a flow battery technology is that we take all the chemicals inside the battery essentially out
and they are stored in an external tank now what difference does that make um well you know i can
tell you right now as an electric chemist there is no battery system that can ever achieve 100
efficiency which means that every time you charge and discharge your batteries the chemicals inside
the pack cell are going to become a little bit imbalanced which means that over cycle
the cycle recycle that chemical imbalance gets bigger and bigger and bigger to the point that
you know you notice your phone is not lasting as long as it used to be at the beginning of the time
now that gives us the advantage however by storing that chemicals outside in the tank when we can do
that that means that we can actually manage the chemical state of charge externally and
that's essentially what the proton pump does is that we have all these chemicals outside in
the electrolyte tank we have a proton pump that's there constantly working to keep the electrolyte
always in balance and that really is a big difference between flow batteries and air and flow
batteries versus a traditional lithium ion or lead acid batteries uh where then that's how we can
achieve cycle to cycle capacity does not fade and performance does not degrade he actually started
in the garage at the at our condo back in 2011 um until we had uh fda stuff came to ask us why
we're getting chemicals delivered to our house and so that eventually had to stop we actually had to
get a real place and so we moved to the portland state business accelerator i think we have like a
200 yeah 200 square foot facility or basically a small lab that's where we did most of our our work
at that point and you guys are now i heard about 140 employees close to 140 employees and instead
of having 200 square feet we now have close to 200 000 square feet so much bigger facility
much bigger labs manufacturing with robots now so it's a big big change ess believes they are
currently at cost parity with something like a tesla mega pack but they believe their long-term
costs might be even more favorable because of their 20 000 cycle lifetimes grid batteries might
charge and discharge more than once in a day given especially challenging circumstances and these are
the sorts of advantages that will loom even larger for the iron flow battery one important thing to
note is that this battery has moving parts it has water pumps and other hardware to facilitate the
charging and discharging process this i believe is why we will never see residential sized iron
flow batteries a lithium-ion battery like a tesla powerwall has zero maintenance to perform
no moving parts and nothing to replace for the life of the battery with the ironflow battery
there will be some sort of a maintenance interval to make sure that there are no
leaks make sure the electrolyte is in balance and make sure that all the pumps are working properly
these sorts of maintenance processes are easy to handle on a grid scale project but could pose some
serious problems for the average consumer so these iron flow batteries from ess are not for cars
or planes not for residential homes what they are is a perfectly thought out highly scalable and
environmentally friendly solution to one of the decades greatest challenges sure we need electric
vehicles but where does the electricity come from for anyone who's ever said evs are just coal
powered cars grid level storage is the counter point we have more than enough sunshine and wind
for all of our energy needs the problem has always been storing it for a cloudy day
i cover a lot of batteries in this channel and i have to tell you i think the ess iron flow battery
might be the most promising battery i've investigated all year the company will
be merging to go public and they're quickly reaching production and shipping to customers
huge vats filled with iron salts might not seem glamorous but this thing just might be one of
the most necessary innovations in decades okay so this is a look at the iron flow battery what
do you guys think am i missing something do i have a good reason to be as excited about the company
and this technology as i am sound off in the comments below that is a look at the iron flow
battery this is one of those technologies that i'm super excited about i think the fact that it uses
really abundant materials is the key because i want to see terawatt hours of energy storage
around the globe and when we start to think about in those scale and in those terms every little bit
really counts so that does it for us huge shout out to all of you guys for watching and thank
you for supporting the show if you want to be a rockstar supporter of the show consider becoming
a patron on patreon or a youtube channel member we call you as a tribe we'd love to have you on
our discord so we can chat and meet up sometimes and you can help with our scripts and plan videos
and uh generally just take a look around there's some other videos that we think you're probably
going to like i'm rick with davinci and just remember the future is going to be awesome