Speaker 1: Welcome to Text Time, a production from my Heart Radio.
Speaker 1: Hey there, and welcome to tech Stuff. I'm your host,
Speaker 1: Jonathan Strickland. I'm an executive producer with I Heart Radio,
Speaker 1: and I love all things tech, and today we're going
Speaker 1: to go to a listener request. Andrew firmly reached out
Speaker 1: on Twitter and asked if I might do an episode
Speaker 1: about redox flow batteries. That's a topic that I've not
Speaker 1: ever touched upon in more than twelve hundred episodes. So
Speaker 1: when you come up with a chance to do something
Speaker 1: you know new, you jump on it. So thanks Andrew.
Speaker 1: To explain this method of energy storage, I will need
Speaker 1: to refer to a couple of things I have covered
Speaker 1: in previous episodes, so maybe not totally new, but this
Speaker 1: is okay. Let's talk about batteries in general. First. Now,
Speaker 1: I'm not gonna go into the history of voltaic piles
Speaker 1: and their evolution in the to the electrochemical battery of today,
Speaker 1: because I've actually done episodes on those topics already, But
Speaker 1: I do need to talk about what is actually going
Speaker 1: on with a battery, how it generates electricity. The fundamental
Speaker 1: thing that is happening with a battery is that it
Speaker 1: is storing chemical energy and then converts that chemical energy
Speaker 1: into electrical energy. Now we all know energy cannot be
Speaker 1: created or destroyed, but you can convert it from one
Speaker 1: type into another. The classic example of potential energy, you know,
Speaker 1: you've got a rock at the top of a hill.
Speaker 1: Transfer that into kinetic energy. You give the rock a
Speaker 1: little push and it begins to move and gravity pulls
Speaker 1: it downward, and you've got kinetic energy as the rock
Speaker 1: is moving. So that goes from potential to kinetic. Well,
Speaker 1: this case we're talking about chemical to electrical, but still
Speaker 1: same sort of concept, the conversion of energy from one
Speaker 1: format to another. Inside a battery are chemicals that undergo
Speaker 1: a reaction that causes a build up of electrons. Those
Speaker 1: electrons gather at the anode. There are two electrodes on
Speaker 1: a battery, the anode and the cathode. The anode is
Speaker 1: the negatively charged end of the battery. It is the
Speaker 1: end that gives up electrons. So the chemical reaction is
Speaker 1: between essentially the electrode at the anode end and the electrolyte.
Speaker 1: But we also know that like charges repel one another, right,
Speaker 1: two negative charges are going to repel each other. It's
Speaker 1: like putting the north end of two different magnets close
Speaker 1: together and they're gonna push against each other. Same sort
Speaker 1: of thing. So each electron is trying to get away
Speaker 1: from all the other electrons. It's trying to maintain the
Speaker 1: ideal amount of space between it and all of its
Speaker 1: fellow negative nancies. Now on the opposite end of the
Speaker 1: battery is the cathode. This is the positive electrode, the
Speaker 1: positive charge due to its own chemical reactions with the
Speaker 1: electro light. Technically, it's drawing in positively charged ions. The
Speaker 1: ions are atoms that have a net charge, whether positive
Speaker 1: or negative. In this case, they are positively charged ions
Speaker 1: or cat ions. Opposite charges attract each other correct so
Speaker 1: negative attracts positive and vice versa. So that means the
Speaker 1: electrons are attracted to that positive side of the of
Speaker 1: the battery, to the cathode end of the battery. But
Speaker 1: unfortunately for these poor little electrons, between them and the
Speaker 1: cathode where they want to go, there's more door. No wait, sorry,
Speaker 1: I read that wrong. Between them is the electro light,
Speaker 1: which in this case acts kind of like a really
Speaker 1: big bouncer who will explain quite convincingly that the electrons
Speaker 1: are not allowed to cross the line. In an electro
Speaker 1: chemical battery, we typically talk about semi permeable barriers or membranes,
Speaker 1: and these allow some types of particles to go through
Speaker 1: but not others. You can think of it kind of
Speaker 1: like a filter, except this particular filter isn't based on
Speaker 1: particle size. Instead, it's based on particle charge. You got
Speaker 1: a positive charge, Hey, you can come on through, but
Speaker 1: only in one direction? Are you a negative nancy aka
Speaker 1: an electron? Sorry, can't get in boss's orders. So in
Speaker 1: this analogy, the cathode is like a popular nightclub and
Speaker 1: the electrons are folks who really want to get in
Speaker 1: there where the party is, but the bouncer just won't
Speaker 1: let them in. But what if there were a side
Speaker 1: door that was unguarded, Well, then the electrons could take
Speaker 1: a different path to get inside the nightclub. And that's
Speaker 1: what happens. When a battery is placed into a circuit.
Speaker 1: The circuit is a path for electrons, and ultimately the
Speaker 1: circuit will connect the anode end of a battery to
Speaker 1: the cathode end of a battery, though it might not
Speaker 1: be the same battery depending on how the circuit arranges batteries.
Speaker 1: We'll talk about putting batteries in series or in parallel
Speaker 1: in a little bit. So when a path is available,
Speaker 1: the electrons politely tipped their imaginary hats to the electrolyte
Speaker 1: bouncer and then they make their way through the circuit
Speaker 1: to get to that positively charged cathode nightclub, where the
Speaker 1: electrons will rejoin chemicals and another reaction will occur. The
Speaker 1: technical term for this type of chemical reaction in which
Speaker 1: there is an exchange of electrons is a reduction oxidation reaction,
Speaker 1: and we can actually look at those chemical reactions at
Speaker 1: the two electrodes that we talked about earlier as the
Speaker 1: two halves of this reduction oxidation reaction. Reduction refers to
Speaker 1: gaining electrons. That sounds counterintuit if I understand, because typically
Speaker 1: you don't refer to something gaining anything as a reduction,
Speaker 1: but in this case is because we're talking about the
Speaker 1: electric charges here, not sub atomic particles. We're talking about
Speaker 1: the reduction of electric charge going more negative, which would
Speaker 1: happen when you take on an electron. So the component
Speaker 1: is accepting electrons and it undergoes a reduction and electric charge.
Speaker 1: Technically it goes from more positive to typically neutral oxidation
Speaker 1: refers to giving up electrons. When an element oxidizes, it
Speaker 1: is losing electrons. So when iron oxidizes, it rusts, and
Speaker 1: if you break off tiny pieces of iron, they oxidize
Speaker 1: so quickly in the atmosphere, and that chemical reaction gives
Speaker 1: off so much heat it does an exothermic reaction, you
Speaker 1: end up with sparks. There is a faster way to
Speaker 1: say reduction oxidation reactions, and that would be redos. So
Speaker 1: that gives you a hint that we're going to be
Speaker 1: coming back to this when we move on to redox
Speaker 1: flow batteries. But we've got a little bit more finishing
Speaker 1: up to do with classical batteries first. Now, typically the
Speaker 1: circuit the electrons must travel through isn't just an open path.
Speaker 1: We expect those electrons to do some work along the way,
Speaker 1: and the electrons don't really care about that. They just
Speaker 1: want to get to that sweet cathode nightclubs. So we
Speaker 1: tell each electron, hey, buddy, i'm gonna let you in,
Speaker 1: but first i'm gonna need your help to light this
Speaker 1: light bulb or pow are this radio or I don't know,
Speaker 1: give my captain Kirk realistic figuring with real gorn punching
Speaker 1: action the ability to hit that jab, and the electrons
Speaker 1: do this always with the goal of getting through it
Speaker 1: to the cathode nightclub. Doing work is hard, but getting
Speaker 1: past the electro light bouncer is physically impossible. I mean
Speaker 1: in the real sense of the word physics, though I
Speaker 1: guess I really should use chemistry. At least, the electrons
Speaker 1: will do the work if they have the energy necessary
Speaker 1: to do that work. So let's say that in our analogy,
Speaker 1: the work that the electrons have to do is to
Speaker 1: lift a very heavy weight, and the electrons all have
Speaker 1: the same amount of energy or weightlifting ability, but collectively
Speaker 1: their ability is not enough to move that heavy weight.
Speaker 1: They can't budget well. In that case, the battery will
Speaker 1: fail to power the circuit. The electrons will not make
Speaker 1: that journey after all, It's almost as if they ran
Speaker 1: into a second bouncer. So the energy that the electrons
Speaker 1: have is dependent upon the standard potential between the cathode
Speaker 1: and the anode. That is, how great is the difference
Speaker 1: between the negative charge on one side and the positive
Speaker 1: charge on the other side. The greater the difference, the
Speaker 1: greater the potential between the two. This gives us the
Speaker 1: batteries overall electrochemical potential, and that in turn determines the
Speaker 1: voltage of the battery. Voltage is akin to pressure, how
Speaker 1: much force is there in the system pushing those electrons along.
Speaker 1: The force determines whether or not electrons flow. If there's
Speaker 1: not enough voltage, the electrons won't move. If there's a
Speaker 1: lot of voltage, they're gonna move too sweet. So if
Speaker 1: the weight is too heavy, if the load on the
Speaker 1: circuit is too great, then it's going to require greater
Speaker 1: force or voltage to do that work with the same
Speaker 1: amount of electrons. Alternatively, you might be able to do
Speaker 1: that work if you had more electrons a larger volume
Speaker 1: of electrons moving through at that lower voltage. This would
Speaker 1: be a description of current or amperage. But one or
Speaker 1: the other needs to go up. If the electrons are
Speaker 1: going to be able to move that weight to to
Speaker 1: power that load on the circuit, there needs to either
Speaker 1: be more of the electrons, or they need to be
Speaker 1: pushed harder, or you know both. It all depends on
Speaker 1: what the circuit can handle and things like that. So
Speaker 1: you can have a high voltage and a low amperage,
Speaker 1: which means you've got a lot of pressure behind a
Speaker 1: relatively small volume of electrons. Or you could have low
Speaker 1: voltage and high amperage, in which a relatively small amount
Speaker 1: of force is moving a relatively large volume of electrons.
Speaker 1: Or you could have any combination. So your typical household
Speaker 1: batteries have a voltage of one point five and these
Speaker 1: would be your classic double A or triple A batteries
Speaker 1: for example. They're all at one point five volts. Okay,
Speaker 1: But let's say you've got a job and it's going
Speaker 1: to be too much for the battery to handle based
Speaker 1: on that batteries voltage, what are your options. Well, you
Speaker 1: could use a different type of battery if your system
Speaker 1: allowed for that battery that had greater electrochemical potential between
Speaker 1: the two electrodes. But the other option is to stack
Speaker 1: the batteries together in series. This has an additive effect
Speaker 1: on the batteries voltage. Now if you were to connect
Speaker 1: the batteries in parallel instead of in series, So in series,
Speaker 1: you can think of them as one right behind the other.
Speaker 1: In parallel, they're all kind of linked up in their
Speaker 1: own individual pathways into the main circuit. Well, if you
Speaker 1: go in PA Hello, you increase the amperage, you increase
Speaker 1: the current, but not the voltage, so it all depends
Speaker 1: on what you need to do. Now, some batteries can
Speaker 1: only do this process one time through all the way
Speaker 1: through it. So once the cathode nightclub gets full of
Speaker 1: enough electrons, it will lose its positive charge. The electrochemical
Speaker 1: potential between the anode and the cathode will decrease. The
Speaker 1: population of electrons at the anode, entrance of the nightclub
Speaker 1: will diminish, and so even if you have a pathway
Speaker 1: that gives electrons a free and clear entry point to
Speaker 1: the cathode with no load to to work, it won't
Speaker 1: matter because there won't be enough electric potential difference for
Speaker 1: there to be any voltage to be any flow of current.
Speaker 1: So essentially the cathode nightclub has reached kind of a
Speaker 1: neutral charge and no electrons are gonna want to go
Speaker 1: there now because it's some lame spot no one cares about.
Speaker 1: The battery is dead and it needs to be discarded
Speaker 1: or preferably recycled. But other batteries are rechargeable, and putting
Speaker 1: them into a charger means that you're actually introducing an
Speaker 1: incoming electric current into the battery, and it forces this
Speaker 1: reaction to reverse itself. The electrons will bail on the
Speaker 1: Cathode nightclub and return to the anode end, and when
Speaker 1: you remove the battery from the charger, it's back to
Speaker 1: where it was before you used it the first time. Mostly, typically,
Speaker 1: rechargeable batteries recapture only a percentage of the full charge
Speaker 1: they once held, which in our analogy would mean some
Speaker 1: of those electrons were just too much in the groove
Speaker 1: and the Cathode nightclub, so they didn't leave when everyone
Speaker 1: else got kicked out. So over time, even a rechargeable
Speaker 1: battery will lose its ability to store energy. The electrochemical
Speaker 1: potential will become too low for the battery to do
Speaker 1: any useful work. I mean, you might be able to
Speaker 1: hook it up to a meter and say, yes, technically
Speaker 1: current is flowing, but it's at such a small amperage
Speaker 1: that it's not useful for anything. I can't do it
Speaker 1: to light a light bulb or whatever. So that's your
Speaker 1: classic battery. There's another energy storage method we should cover
Speaker 1: as well, as it's going to be useful. When we
Speaker 1: talk about redox flow batteries and that would be fuel cells.
Speaker 1: Fuel cells are similar to, but distinct from batteries. Sir
Speaker 1: William Robert Grove, a Welsh judge, generally gets credit for
Speaker 1: inventing the first fuel cell all the way back in
Speaker 1: eighteen thirty nine. I guess this tells us that Welsh
Speaker 1: judges had a lot of spare time on their hands
Speaker 1: in the mid nineteenth century. Basically, Sir Willie found out
Speaker 1: that by mixing hydrogen and oxygen in the presence of
Speaker 1: an electro light would end up with some interesting byproducts.
Speaker 1: He would get water, you know, good old H two
Speaker 1: O two hydrogens to one oxygen and electricity. But this
Speaker 1: particular incarnation of a fuel cell, well interesting, wasn't practical
Speaker 1: because it wasn't producing enough like tricity to do anything
Speaker 1: of use. However, we're gonna skip way ahead. Fuel Cells,
Speaker 1: like batteries, convert chemical energy into electric energy. There are
Speaker 1: many different kinds, but the ones you and I would
Speaker 1: most likely encounter are those that use hydrogen and oxygen,
Speaker 1: much like Sir Williams fuel cell from more than a
Speaker 1: century ago. In a fuel cell, you've essentially got a
Speaker 1: couple of chambers separated by a semi permeable membrane. In
Speaker 1: one chamber you pump in hydrogen and in the other
Speaker 1: chamber you pump in oxygen. The semi permeable membrane is
Speaker 1: an electrolyte, typically paired with a catalyst, and a catalyst
Speaker 1: is something that facilitates a reaction. It doesn't cause a
Speaker 1: reaction on itself, but it makes reactions easier. It reduces
Speaker 1: the the energy requirement for a reaction to happen. So
Speaker 1: the hydrogen atoms, which consist of one electron and one
Speaker 1: proton that's a hydrogen atom, they react with this electrolyte
Speaker 1: and the catalyst. This causes the hydrogen atoms to say
Speaker 1: bone voyage to that electron. So you get a positively
Speaker 1: charged hydrogen ion or the cat ion, and that would
Speaker 1: be the positive hydrogen uh anions are then negatively charged ions,
Speaker 1: thus like cathode and anode, and we have another word
Speaker 1: for hydrogen ions that would be a proton, because that's
Speaker 1: all a hydrogen nucleus really is. It's one proton, so
Speaker 1: positively charged sub atomic particle. The semipermeable membrane allows the
Speaker 1: proton to pass through it, but not the electron. So
Speaker 1: like our previous example, the electrons really want to get
Speaker 1: to that other side of the membrane because that's where
Speaker 1: a positive charge exists. So you can connect the fuel
Speaker 1: cell to a circuit and the electrons will travel through
Speaker 1: that path and head toward the opposite chamber and they'll
Speaker 1: do work. They'll do work on an electric load along
Speaker 1: the way. How much depends again upon the electrochemical potential
Speaker 1: between the two electrodes, the anode and the cathode. And
Speaker 1: then they'll get over to where all the oxygen and
Speaker 1: hydrogen uh nuclei, the protons, those cat ions all happen
Speaker 1: to be. Now, I have a little bit more to
Speaker 1: say about fuel cells, but before I get into that,
Speaker 1: let's take a quick break. So before we left off,
Speaker 1: I mentioned that the hydrogen in a fuel cell gets
Speaker 1: stripped of its electron. The hydrogen cation or proton, passes
Speaker 1: through this semi permeable membrane. The electron goes through a circuit,
Speaker 1: doing work along the way before finally making its way
Speaker 1: to the other chamber in the fuel cell. In that
Speaker 1: opposite chamber, the protons, electrons, and oxygen combined to form water.
Speaker 1: This is also an exothermic reaction, meaning it gives off heat,
Speaker 1: So your byproducts of this reaction are electricity, heat, and water.
Speaker 1: The fuel cell only generates electricity so long as there
Speaker 1: is hydrogen and oxygen a k a. The fuel that's
Speaker 1: in the cell, and that means that once it runs
Speaker 1: out of those, you have to refuel it. This is
Speaker 1: not something that just stays contained within the fuel cell.
Speaker 1: You're refueling it, just as you would have to refuel
Speaker 1: something like a car, you know, to top it off.
Speaker 1: And it is a clean process within the fuel cell
Speaker 1: itself because the byproduct is pure water. People have advocated
Speaker 1: for fuel cells to replace stuff like gasoline or diesel
Speaker 1: powered vehicles. So what's stopping us? What is in the
Speaker 1: way of doing that? Well, there are a few challenges,
Speaker 1: and one is that hydrogen is actually not that easy
Speaker 1: to come by. Now what do I mean by that?
Speaker 1: I mean, we know hydrogen is the most plentiful stuff
Speaker 1: in the universe, so you figure it would be the
Speaker 1: easiest stuff in the world to get hold of. But
Speaker 1: hydrogen also tends to bond with other stuff. In its
Speaker 1: pure form, hydrogen is a gas and it's lighter than air,
Speaker 1: so it floats off beyond our reach. We typically get
Speaker 1: hydrogen through some other process which involves breaking the molecular
Speaker 1: bonds that hold hydrogen to other elements. But that means
Speaker 1: you have to actually pour energy into this process. In
Speaker 1: order to get to the hydrogen, you have to break
Speaker 1: those molecular bonds. That requires using energy. So to swap
Speaker 1: out to a hydrogen based system, you have to take
Speaker 1: that part into account. Now, if it turns out you're
Speaker 1: using more energy to get the hydrogen, then you would
Speaker 1: get energy by harnessing that hydrogen. You're playing a losing game, right.
Speaker 1: If you're spending more energy just to get the fuel,
Speaker 1: then you are being able to use the fuel. Why
Speaker 1: are you doing that? You should just choose some other method.
Speaker 1: Or if the method you're using to break those molecular
Speaker 1: bonds doesn't depend upon an environmentally friendly method, then really
Speaker 1: you're just shifting pollution to a different part of the system. Now,
Speaker 1: you can get hydrogen out of water by running an
Speaker 1: electric current through the water. In fact, this is essentially
Speaker 1: the same process we see in fuel cells, but in reverse, right,
Speaker 1: because in fuel cells we see hydrogen and oxygen binding
Speaker 1: together and the byproduct in this is electricity and some heat.
Speaker 1: By running an electric current through water, we can break
Speaker 1: up oxygen and hydrogen, and you know, we break that
Speaker 1: molecular bond, so again the same process, but in reverse.
Speaker 1: It's actually called electrolysis. But in order to do that,
Speaker 1: you have to have access to suitable water. You need
Speaker 1: a clean method to generate electricity, maybe use solar power
Speaker 1: or wind power, And all of this starts raising questions
Speaker 1: about why would you not just use solar or wind
Speaker 1: power directly, So you couldn't really do that for like
Speaker 1: an onboard system on a car, and the counter argument
Speaker 1: is that you still have to have a way to
Speaker 1: store energy. Fuel cells would be a way to help
Speaker 1: store energy, but there are other challenges besides the access
Speaker 1: to hydrogen. Another big one is that most fuel cells
Speaker 1: have a band of temperatures within which they can operate,
Speaker 1: and if you get outside that band of temperatures, if
Speaker 1: you go too high or too low, the fuel cell
Speaker 1: will not perform as well and it might even suffer damage,
Speaker 1: which means it will have a much shorter life cycle. Anyway,
Speaker 1: most fuel cells don't operate very well below a certain
Speaker 1: threshold temperature. The specific temperature threshold really depends upon the
Speaker 1: type of fuel cell, and this makes them a little
Speaker 1: less reliable if you want to, I don't know, have
Speaker 1: a fuel cell powered car in Alaska in the middle
Speaker 1: of winter, the temperatures can actually get low enough where
Speaker 1: it's below the real operating temperatures for that fuel cell,
Speaker 1: and it might even do damage to the fuel cells membrane.
Speaker 1: So this is a tricky problem to get around. And
Speaker 1: yet another challenge is that many fuel cells rely on
Speaker 1: rare and expensive materials to act as catalysts, such as platinum.
Speaker 1: And yet another challenge is that many fuel cells rely
Speaker 1: on rare and expensive materials to act as catalysts such
Speaker 1: as platinum. Platinum is expensive stuff, and that drives up
Speaker 1: the cost of manufacturing. As much as I wish we
Speaker 1: could all ignore the impact of money, we can't. If
Speaker 1: you have two ways to store energy, and one is
Speaker 1: relatively cheap but environmentally it's harmful, the other is expensive
Speaker 1: but has no real negative environmental impact, some people, perhaps
Speaker 1: most people, are going to go with the less expensive option,
Speaker 1: even though in the long run you could argue that
Speaker 1: it's more expensive and to have a true hydrogen based economy,
Speaker 1: you would also have to invest in building out a
Speaker 1: new infrastructure, which can run into the billions of dollars,
Speaker 1: so it's another big challenge. Also, I should point out
Speaker 1: that while the actual chemical reaction within a hydrogen based
Speaker 1: fuel cell is a clean one, there can be other
Speaker 1: factors that cause a negative environmental impact, including the mining
Speaker 1: methods that you have to rely on to get the
Speaker 1: materials for the catalyst. You always have to take a
Speaker 1: big picture look at these things and not just look
Speaker 1: at the mechanism of the fuel cell itself. You gotta
Speaker 1: look at the whole ecosystem and say, does this make
Speaker 1: more sense than fossil fuels. I would argue it does,
Speaker 1: but you have to take the whole picture into account
Speaker 1: before you can actually say something like that. And I'm
Speaker 1: not saying all of this to completely dismiss fuel cells,
Speaker 1: because I happen to love fuel cell technology, but I
Speaker 1: also believe we have to acknowledge the obstacles that are
Speaker 1: in our way if we ever are to have a
Speaker 1: hope of surmounting those obstacles. Now, let's finally move on
Speaker 1: to redox flow batteries. Now, luckily, with the grounding we
Speaker 1: have of in traditional batteries and with fuel cells, we
Speaker 1: can tackle this concept a bit more easily. Lawrence H.
Speaker 1: Thaller filed a patent for an electrically rechargeable redox flow
Speaker 1: cell back in nineteen. The Patent Office in the United
Speaker 1: States granted that patent the following year. The abstract gives
Speaker 1: us a really useful starting points, so I'm gonna read
Speaker 1: it in full. Also, this patent expired in so this
Speaker 1: is about as fair use as it gets. But here's
Speaker 1: the abstract. There is disclosed a bulk energy storage system
Speaker 1: including an electrically rechargeable reduction oxidation redox cell, divided into
Speaker 1: two compartments by a membrane. Each compartment containing an electrode
Speaker 1: and anode fluid is directed through the first compartment at
Speaker 1: the same time that a cathode fluid is directed through
Speaker 1: the second compartment, thereby causing the electrode in the first
Speaker 1: compartment to have a negative potential while the electrode in
Speaker 1: the second compart mint has a positive potential. The electrodes
Speaker 1: are inert with respect to the anode and cathode fluids used,
Speaker 1: and the membrane is substantially impermeable to all except select
Speaker 1: ions of both the anode and cathode fluid. Whether the
Speaker 1: cell is fully charged or in a state of discharge.
Speaker 1: Means are provided for circulating the anode and cathode fluids,
Speaker 1: and the electrodes are connected to an intermittent or non
Speaker 1: continuous electrical source, which, when operating, supplies current to a
Speaker 1: load as well as to the cell to recharge it.
Speaker 1: And sillery circuitry is provided for disconnecting the intermittent source
Speaker 1: from the cell at prescribed times and for circulating the
Speaker 1: anode and cathode fluids according to desired parameters and conditions.
Speaker 1: And that's the abstract. Now. I'm sure a lot of
Speaker 1: you out there are way up to speed with what's
Speaker 1: going on. But for those of us like me who
Speaker 1: find the language of patents to be a teen c
Speaker 1: bit difficult to parse, let's break it down, and we're
Speaker 1: gonna start with the core, the cell of this flow
Speaker 1: battery where the electricity gets generated. This core has two compartments,
Speaker 1: each with its own electrode. One electrode the anode, is
Speaker 1: the negative terminal, the other, the cathode, is the positive terminal.
Speaker 1: And this is just like a battery or a fuel cell.
Speaker 1: A liquid electrolyte pumps into each side of the core.
Speaker 1: In between the two compartments is a membrane separates the
Speaker 1: two cores. In between the two compartments is a membrane
Speaker 1: that separates those two compartments, right, it's right there in
Speaker 1: the middle, and it allows certain ions, certain charged particles
Speaker 1: to pass through, but not electrons. These compartments connect to
Speaker 1: respective electrolyte tanks, so big reservoirs, and the tanks hold
Speaker 1: the positive or negatively charged ions. Pumps on either side
Speaker 1: take the respective electrolyte from the respect tank and pump
Speaker 1: it into the respective compartment in the cell, and then
Speaker 1: within the cell, the ion exchange can happen across the
Speaker 1: membrane the anode side or the analyte because that's anode
Speaker 1: plus electrolyte releases electrons in this process, which then can
Speaker 1: go on and do work in a circuit before joined
Speaker 1: the cathode plus electrolyte on the other side. The respective
Speaker 1: liquid electrolytes now continue to move out of the cell
Speaker 1: and back into their various tanks. However, this means that
Speaker 1: the electrolytes are now chemically different because of that ion
Speaker 1: and electron exchange. They're no longer the same ions that
Speaker 1: they were when they were being pumped into the cell
Speaker 1: and having that exchange right now they're inert, at least
Speaker 1: with respect to each other. They no longer will have
Speaker 1: that reaction. You won't have that electrochemical potential where that
Speaker 1: exchange could happen again. So let's say you've pumped through
Speaker 1: the entire air supply of electrolyte through both tanks. You know,
Speaker 1: it's been pumped all the way through and refilled, and
Speaker 1: now we've got these inert electrolytes. You would eventually find
Speaker 1: you are no longer producing any electricity because enough of
Speaker 1: the electro light has gone through this exchange that the
Speaker 1: electric potential between the cathode and anode is no longer
Speaker 1: sufficient for that to continue. So it's kind of like
Speaker 1: having a dead battery. However, this process can be reversed,
Speaker 1: just as with a rechargeable battery. So if you pour
Speaker 1: the electricity into the system, you cause the reverse of
Speaker 1: this chemical reaction. You recharge the electrolytes that are on
Speaker 1: either side, that are in either compartment, so that once
Speaker 1: again you have negatively charged electro light on the anode
Speaker 1: side and positively charged electro light on the cathode side,
Speaker 1: And you would pump these electro lights through the cell,
Speaker 1: they would get recharged then they would go back into
Speaker 1: their tanks, so you're gradually reach our ing all the
Speaker 1: electro light that are in either tank until your back
Speaker 1: up to full capacity. This reminds us that batteries are
Speaker 1: not a source of energy. They are a form of
Speaker 1: energy storage. We have to put energy into them in
Speaker 1: order to get energy out, so we're not like mining
Speaker 1: electricity here. And now we're getting into how these batteries
Speaker 1: might be used. So let's say you've got a farm
Speaker 1: of solar panels and they're generating electricity. It's a bright
Speaker 1: sunny day and they're generating electricity like gangbusters. That electricity
Speaker 1: needs to either be put to work immediately or it
Speaker 1: has to be stored otherwise it goes to waste. And
Speaker 1: this is true of any method of generating electricity, by
Speaker 1: the way, not just with solar panels, but with traditional
Speaker 1: power plants. Our power plants try to match production to
Speaker 1: meet demand, but sometimes demand is low, such as say
Speaker 1: in the middle of the night when most folks sleep,
Speaker 1: and the power plants then have options. They can try
Speaker 1: in store excess energy in some other form and some
Speaker 1: other solution so that it doesn't just go to waste.
Speaker 1: One way of doing This is through hydro pumping, and
Speaker 1: I want to describe this because there's some analogies between
Speaker 1: hydro pumping and redox flow batteries. Hydro Pumping is a
Speaker 1: fairly simple idea. Let's imagine that you've got two reservoirs
Speaker 1: of water, but one is at a higher elevation than
Speaker 1: the other, so it's up a hill. From the higher reservoir,
Speaker 1: you have a tunnel. This is called the intake tunnel.
Speaker 1: That tunnel leads down into a powerhouse under the ground,
Speaker 1: and that powerhouse contains a turbine that water can turn.
Speaker 1: So water flowing down due to gravity hits this turbine
Speaker 1: and the force of it causes the turbine to rotate.
Speaker 1: This powers and electrical generator, generating electricity. As the name implies.
Speaker 1: The water then continues to flow out a second tunnel,
Speaker 1: the discharge tunnel, and this tunnel empty is out into
Speaker 1: the lower reservoir. So effectively, water is just flowing downhill, right.
Speaker 1: It's coming from an upper reservoir down through a tunnel.
Speaker 1: Happens to have to do some work along the way,
Speaker 1: and then continues down until it hits the lower reservoir.
Speaker 1: It just needs gravity to work. But to recharge the system,
Speaker 1: the powerhouse turbine has to actually be activated. We have
Speaker 1: to pour energy into it and turn the turbine in
Speaker 1: the opposite direction. Now it's acting like a pump, and
Speaker 1: it forces water from the lower reservoir and pumps it
Speaker 1: up against gravity into the upper reservoir. So when a
Speaker 1: power plant is generating more electricity than the current demand requires,
Speaker 1: it could send that excess electricity over to the hydro
Speaker 1: pump station. The hydro pump station activates and begins to
Speaker 1: pump water from the lower reservoir into the upper reservoir,
Speaker 1: and then they have that energy stored. But if the
Speaker 1: power plant ends up seeing a demand for electric see
Speaker 1: that exceeds its own ability to produce electricity, the hydro
Speaker 1: pump can jump into action and it can open up
Speaker 1: those tunnels and allow gravity to have water turn a generator,
Speaker 1: and thus you get to augment the power plants capability
Speaker 1: of producing electricity. So again it's just storing energy. Well,
Speaker 1: the same sort of thing is happening with the redox
Speaker 1: flow batteries and for much the same purpose, except instead
Speaker 1: of using gravity and kinetic energy to provide what we need,
Speaker 1: we're talking about an electrochemical process. We're still using pumps
Speaker 1: to circulate liquid electrolyte from reservoirs through an electric cell,
Speaker 1: but we discharge the redox flow battery by having this
Speaker 1: ion exchange, and the active elements in these reservoirs begins
Speaker 1: to reduce and we recharge by reversing the process, we
Speaker 1: pump electricity back into the battery to recharge the respective
Speaker 1: electrolytes so that the tanks are full of active components.
Speaker 1: The capacity of a redox flow battery depends upon the
Speaker 1: size of those tanks. The electrochemical potential of a redox
Speaker 1: flow battery will always depend upon the specific electric lights
Speaker 1: being used. It doesn't matter if you have more or
Speaker 1: less of them, So you choose your electrolytes that's going
Speaker 1: to determine that electrochemical potential. So in other words, that
Speaker 1: determines what the voltage of your battery is going to be.
Speaker 1: And it doesn't matter if you have small tanks full
Speaker 1: of the stuff or big tanks full of the stuff.
Speaker 1: The difference is that the size of the tank determines
Speaker 1: the capacity, the amount of energy overall that it can store,
Speaker 1: and that depends not just on the size of the tank,
Speaker 1: but also on which electro lights you choose. Some electro
Speaker 1: light pairings are more energy dense than others. Some are
Speaker 1: more energy dense but much more toxic, or they're more
Speaker 1: expensive or both. So there are a lot of different
Speaker 1: considerations you have to make when you're choosing your electrolytes.
Speaker 1: But the size of the banks you're really just limited by.
Speaker 1: You know, your facility, and if you have the facility
Speaker 1: to make a truly enormous pair of tanks, then you've
Speaker 1: got a battery that's got an enormous capacity to store energy.
Speaker 1: They're not going to release that energy all at once,
Speaker 1: but it's going to store a lot of it. And
Speaker 1: like traditional batteries, you can actually connect redox flow batteries
Speaker 1: in series, so you can create a higher voltage that
Speaker 1: way too. Instead of having to swap out what electrolytes
Speaker 1: you plan on using, you could just make a series
Speaker 1: of these redox flow batteries and get a higher voltage
Speaker 1: by connecting them that way. Now, when we come back,
Speaker 1: I'll talk a bit more about some of the types
Speaker 1: of electrolytes used in these redox flow batteries, since again
Speaker 1: it determines the voltage as well as the use cases
Speaker 1: for the batteries and some recent advancements in that technology.
Speaker 1: But first let's take a quick break. So from the
Speaker 1: moment they were first invented in the late sick season
Speaker 1: and patented in the seventies to present day, the choice
Speaker 1: of which materials to use as the anode and cathode
Speaker 1: electrolytes have guided the evolution of the redox flow battery.
Speaker 1: Early redox flow batteries included a zinc chlorine pairing chlorine
Speaker 1: is incredibly dangerous stuff, zinc bromine, Later zinc serrium batteries
Speaker 1: were used. Vanadium based redox flow batteries have been used,
Speaker 1: and lots of others, and they have a range of
Speaker 1: capabilities when it comes to stuff like electrochemical potential, energy density,
Speaker 1: power density, toxicity, cost, and recycling. Recycling by the way,
Speaker 1: I don't mean to recycle the materials, but rather how
Speaker 1: many recharge cycles does this battery have? How many times
Speaker 1: can you charge it back up to full and discharge
Speaker 1: it in full and not lose any energy storage capacity.
Speaker 1: Rarer elements are obviously more expensive, that's kind of a given,
Speaker 1: and some of these are actually more like hybrid style
Speaker 1: redox flow batteries which require some extra components, or they
Speaker 1: include specially treated electrodes where one of the two electrodes
Speaker 1: has UH elements on it that make it either the
Speaker 1: anode or the cathode. The zinc ones also have to
Speaker 1: contend with a tendency for zinc to coat the electrodes.
Speaker 1: You get almost like an electro plating, but it's of zinc.
Speaker 1: And if that happens enough, then the electrodes has become
Speaker 1: less effective. They're no longer able to transmit electrons, so
Speaker 1: you eventually have to strip those plates of that zinc coding.
Speaker 1: More recently, researchers with the University of Southern California announced
Speaker 1: that they were working on a redox flow battery that
Speaker 1: uses an iron sulfate solution, and that is super cheap
Speaker 1: to get hold of because it's a byproduct from the
Speaker 1: mining industry. It's essentially waste. So the other component in
Speaker 1: this particular approach is an acid called an stick with
Speaker 1: me guys an through quine known disulfonic acid and I'm
Speaker 1: sure I mess that up, but it's a q DS
Speaker 1: is how everyone refers to it, because no one wants
Speaker 1: to say that name. Now, one major advantage of this
Speaker 1: entire approach that the University of Southern California researchers have
Speaker 1: suggested is cost because the components are plentiful and they
Speaker 1: are inexpensive, so it brings down the cost per kill
Speaker 1: a lot hour of providing electricity using this method, and
Speaker 1: that's a big deal. Now. In addition, these batteries again
Speaker 1: have different cycle capacities, so that whole discharge recharge cycle
Speaker 1: redox flow batteries typically have hundreds or thousands of cycles,
Speaker 1: sometimes between ten and twenty thousand cycles, which means that
Speaker 1: you can use the same supply of liquid electrolytes over
Speaker 1: and over. In fact, some people say that they effectively
Speaker 1: have an indefinite number of recharge icals. It's really the
Speaker 1: other components that you have to frequently swap out, like
Speaker 1: you will eventually have to replace the pumps or you
Speaker 1: may have to replace the electrodes or the membrane, but
Speaker 1: that the electro light fluids for a very long time
Speaker 1: will just be stable. The redux flow battery is good
Speaker 1: for the load balancing applications that I mentioned earlier with
Speaker 1: power grids, and compared to some other battery technologies like
Speaker 1: lead acid or lithium ion batteries. Redux flow batteries tend
Speaker 1: to have lower power and energy densities. They can't hold
Speaker 1: as much, but they work well with large applications like
Speaker 1: power grids, and they scale right, so there's a balance there. However,
Speaker 1: the requirements of the redux flow battery are such that
Speaker 1: they are not good for smaller applications, which you could
Speaker 1: easily imagine. Right, you're not going to have these for
Speaker 1: your cell phone. They're not good for portable or tiny applications.
Speaker 1: The requirement of the reservoir tanks means this tech does
Speaker 1: not scale down well. You would want this for large
Speaker 1: stationary applications, so you could pair it with stuff like
Speaker 1: green or energy technologies like I had mentioned before the break,
Speaker 1: like the solar panel farm, because with wind power or
Speaker 1: solar power, redox flow batteries can help balance out the
Speaker 1: natural drawbacks of those methods. We know the sun doesn't
Speaker 1: shine all the time because that slacker takes practically every
Speaker 1: single night off, nor does the wind always blow. So
Speaker 1: using energy storage to help balance the load during times
Speaker 1: where you cannot easily produce electricity directly is critical. You
Speaker 1: need some way to store the energy when you're producing
Speaker 1: a lot of it and some way to release the
Speaker 1: energy when you're not able to produce it. And that's
Speaker 1: really one of the key elements for going with a
Speaker 1: renewable green energy source. Bringing the cost down on that
Speaker 1: energy storage makes renewable energy solutions much more viable. It's
Speaker 1: a it's a key component of doing that. And as
Speaker 1: I mentioned earl here, if you have a renewable method
Speaker 1: to generate electricity and you have one that relies on, say,
Speaker 1: fossil fuels, and you've got a pretty high price tag
Speaker 1: for your renewable energy, it's hard to get a lot
Speaker 1: of people to switch, or maybe hard to get large
Speaker 1: power companies to switch. After all, the economically viable option
Speaker 1: is to go with the lower cost so you get
Speaker 1: higher return. You don't want to spend more money and
Speaker 1: make less money, at least not from the perspective of business.
Speaker 1: If we take that from a perspective of environmental impact,
Speaker 1: there's a different argument to be made. But we have
Speaker 1: to remember we live in the real world where all
Speaker 1: of these factors are playing a part making the whole
Speaker 1: enterprise economically advantageous. By enterprise, I mean renewable energy. That's
Speaker 1: a huge move and we're starting to see it already.
Speaker 1: I mean, we've already seen the price of energy production
Speaker 1: through renewable technologies to come down significantly to the point
Speaker 1: where it's actually very competitive with fossil fuels, in some
Speaker 1: cases more advantageous. And having this component, the energy storage component,
Speaker 1: be part of that is critical. But that's pretty much
Speaker 1: all I have to say about REDOS flow batteries. To
Speaker 1: get into more detail would really just involve talking about
Speaker 1: the specific ion exchanges with each pairing of electrolyte materials,
Speaker 1: which would become a chemistry lesson, or talking about how
Speaker 1: much energy those individual electro LTEs hold per unit of
Speaker 1: volume and how expensive they are, which would becomes sort
Speaker 1: of a cost benefit analysis of the different types of electrolytes.
Speaker 1: And really I'm not keen to do either of those things.
Speaker 1: But the important things we've covered the basic technology of it.
Speaker 1: So you're not likely to encounter a flow battery for
Speaker 1: home use, but some large buildings might take advantage of
Speaker 1: one as part of a load balancing UH strategy or
Speaker 1: backup generator strategy. More likely, power plants and renewable energy
Speaker 1: facilities will use them, as I've said, but you never know.
Speaker 1: But I do think it's a pretty interesting technology, one
Speaker 1: that relates very closely to those others that I mentioned before,
Speaker 1: but is different enough where I thought it was cool
Speaker 1: to really tackle it. If you guys have any suggestions
Speaker 1: for me to cover in future episodes of tech Stuff,
Speaker 1: whether it's a specific technology, maybe it's a company or
Speaker 1: a person in tech, Maybe it's just a trend in
Speaker 1: tech that you want to know more about, let me know.
Speaker 1: You can reach out to me on Twitter or Facebook.
Speaker 1: The handle for both of those is text stuff H
Speaker 1: s W and I'll talk to you again really soon.
Speaker 1: Text Stuff is an I Heart Radio production. For more
Speaker 1: podcasts from I Heart Radio, visit the I Heart Radio app,
Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.