Tech Talk - Gaskets in Fuel Cells - Hydrogen Technology Explained - Hyfindr Hickmann
Hello, my name is Steven. Welcome to Hyfindr Tech Talks, where we aim to understand the technology that makes the hydrogen economy work. Today, we will be speaking about gaskets. Now, gaskets have it in themselves as they say and I will be speaking about this topic with someone who's really revert.
He has earned several innovation prizes and he's CEO and managing director of Eisenhuth, a company that works in the hydrogen sphere obviously but also on the medical side and for automotive manufacturers have made gaskets for years and he's been working in this area really a lot. It is my very special pleasure to welcome Dr. Thorsten Hickmann. Yeah, hello. Welcome Thorsten. Hello. It's great to have you here and yes, today we want to talk about gaskets. So, let's start from the basics. What
is a gasket? Well in fact the gasket is the most underestimated part in the fuelcell or an electrolyzer because you always think of the membrane of the bipolar plate and then just put it together and gasket is no big thing, but then the story begins or the problem occurs. So, we have to see, we have to find a solution to get a system which has no leakage. No leakage from A to B but also no leakage of intern to extern. So, this is a function of the gasket to take care that there is a material inside and doesn't go out and keeps on the place where it should be. Okay. Well. So, that means essentially it is a seal. Right. It is sealing the system and if we
look at the slide, I can also explain it a little bit in a small drawing. Yes. You see here on the right side, you see here a cut through a fuel cell or a cut through an electrolyzer. Yes. Okay, sorry for the abbreviations but BPP is Bipolar Plate. Yeah. GDL is gas diffusion layer. MEA is Membrane Unit and well which is not abbrevated is a gasket but this is just by occasion,[I crlearly see what's important to you] that's true but at the end of the day, well this the community uses the abbreviations. So, I stick to them as well. However, you see in the drawing
here, what is the gasket doing. So, you have the mayor in the middle and then you have the gaskets so and then you have the bipolar plate. So, first role; first function is or what is this doing is that it is responsible that the gases which come from the bipolar plate go into the direction of the membrane that they stay there. Yeah. The second function you can see on the drawing as well is that there's no gas going
outside. Yes. Well sometimes when we have graphetic bipolar plates also gas kick here in between so that they are between two bipolar plates, however, in this picture it is not the case but then you have the gasket as well. Yeah. I see you both also brought one with here which I'm very grateful for. So, we just saw this. So, is this
what we are seeing here? And we need to hold it a little bit closer. Yeah, basically it is, you see here's a blue thing and you see here the inlet and the outlet area and then the flow field and well this is also showing that here on the bipolar plate, it is important that here in the manifold the material comes from the outside through different plates and then here it goes into the flow field area but the way must be go beneath the plate into this area so that's all that's the way how it is working but it is not allowed that goes from here directly to the flow field. So, we have the connection. Yes, exactly. Yes, it's keeping that. Okay, so, where do we find gaskets in the hydrogen economy. Yeah. Well, basically
all over. I really watched your interesting stories about valves and all the other things. So, also here you have a gaskets and sealing. So, you have it basically in each component but today I focus on the stack and in the stack you have it between the bipolar plate on the one hand and the membrane unit on the other end basically. Yes. Alright. So, you have different
kinds obviously as far as I understand. Well at the end of the day, I mean the one thing is to have a solution the other thing have a solution which is also very cost effective. Yes. So, when we are talking about big volumes then the issue is that we want to have it integrated with other components. Okay. And I have here a small slide, which we can explain it again.
So, here we have on one picture, the different options you have. I start in the corner here on the below. So, this is the first option where you start with this is separate gasket, yes. Maybe we can also have a look at it. Like here you see it. So, this is flexible this is and then this is the way we do and later on we can discuss again. Yeah, that's the way. Yeah, okay. Okay but then the community says we are but this is very difficult to handle and so on which is only the half of the truth. However, there
are a lot of action to integrate it on the other components. So, what other components do we have. We have the bipolar plate. We have the GDL and we have the membrane unit. So, that's what we see on here. We see on the left corner here the MEA. Yes. We see the graphatic bipolar plate, where we have also shown a picture of it, then we see here the metallic bipolar plate and you see here in the corner that there is a gasket all around and another option is to use instead of the MEA, the GDL. So, this is then stick to the GDL and this will be added to the MEA on a separate step later on after the gasket is on it, but then we do not have any longer two components or a separate component for the gasket but we have only an integrated solution with an already existing component. That's the idea. Is this
what we see here? Yes, this is in fact maybe for a smaller system on the GDL integrated and this is already; this is also a gasket for electrolyzer test system. So, we do it here already at the even at a low volume to have integration here and you see that there is no material flowing into the GDL. So, there's an exact line between the gasket on the one side and the GDL on the other side. So, this is working quite nicely. Okay. Yeah. So, I know I mean when we're talking about these kind of things, I mean we've seen some material here and what kind of materials are we talking about? Is anything good for hydrogen? Well, yeah maybe, we can look at another slide again. Yes. So, in fact when we talk about gaskets or sealing, you see well it even it is hard to read all the names but you see by the circuits already there a bunch of different materials and I have I've added 3 arrows here.
So, the red one is a so-called VMQ. So, VMQ. This is for silicon. This is very often and very well used material. However, for higher temperature you can use a Fluor Elastomere material or what we very often use, because it has a better pricing and has a better performance against hydrogen, is the so-called EPDM. So, it is kind of a synthetical rubber. Okay. Well, I will not explain you the
detail what is EPDM. It is very complicated. I mean however I see you I have a couple of abbreviations going. Well, this is what let's say the rubber expert use. However, you see already that there's a big range of possible material. We stick to the three materials, where we have good experience and it is also question, how to produce them and the reason why we have the red the silicon is in fact the material, which is very often used and it has a very good process options. And you brought this thing here. Is this silicon? This is yeah. This is a sample, how to explain
a different, I mean if we talk about gasket the story already begins. The first thing was a material, but now we talk what kind of gasket and then we talk about hardness. So, this is the gasket world. The gasket people they have a special value for it. It is shore. Okay. However, you do not need to remember it, but what is important is it's a different hardness type is and you see here on this, on this video and on the screen that the transparent silicon is very soft material and if you look on the other corners, it's the black material. This is very hard. It's almost not bending. Yeah. So, the question is what to use, the experience says good
is always in the middle because then you can do good processing. So, these numbers are they the shore value. Yeah, there are numbers written on it. I don't think you can see it on the screen but the transparent is 10 and 20 and so on and the middle ones is between 50 and 60 the green and the blue ones, which are the ones which we usually recommend to our customers, because then you have a good way, how to produce them and a very good way how to make a sealing on it. Yes. So Thorsten, if you can
please just take us maybe one step deeper and get into like you know like putting the gasket on how does it hold? And I mean I've also wondered like how does it actually prevent you know this gas going through? And how do you put it in place? Yeah. Well. Maybe we can look at the next slide again. So, one option is that you use kind of O-ring shape or also a flat gasket and here you see on the left side this original design and then this is a compressed version so under pressure and then this on the right side is the so-called compression set that means what is happening, if the gasket is going back when the system is opened. You usually do not want to have the system open. However, this is a very important value because if you look at
the long usage application or a long time usage, then you want to have that the performance will be not only at the beginning, it must be also after 5000 or 10,000 hours. So, this is very important and you see, it is already very important, how to do here and I don't think it is necessary to deep now what to consider at the O-ring. There's also a lot of literature in the internet you can see. So, this is a very good way to start and to get used to it. Yes, but this is like a cross-section of O-ring and essentially is lying on some material and and when it gets compressed, it changes the shape. Yeah. So, that's very important. So, if you design a system you must consider that you have enough space, which is here. So, it is not good to go to the
original size of the ring and then press it into the plate and what will happen the material is like water. So, it cannot be compressed. It can only go to the side. So, you have to have enough side that it is able to be compressed. Okay. So, this is very crucial that you have enough space on the left and right side of the gasket or the sealing. That in this case o-ring but this is a
general rule. So, that it is able to be compressed but the dimension or the the area will keep the same since cannot be compressed but it will be get thinner, let's say. Okay and well I mean like the other gaskets that we saw they were they were not old they were flat. Yes. So, is these other kinds of gaskets? Well. The thing is I mean, if you in this case you can see in the literature, when you read it, it's good if you have two components. The O-ring is perfect. You compress them and then it's nice, but we're talking about the stack. So, we have hundreds of plates on
it on top of each other and then you have the force for compressing it at exactly is the same area 400 times and this means you need to have a lot of energy and if you have graphatic plates, they might break. Yes. Metal plates might work. However, it's not good for them but this is not, it's an option but there are also other options, let's say this way around and the other option is that if we see now at the next slide is that we take a kind of profiled gasket. Okay, this is again a cut. So, you must imagine that it is going all around it with this shape and here and you see is a dimension on the right side it's very small only 1.26 mm
and there's even a foil in between for for better stability, which is also used in the community. However, we talk about 0.7 millimeter. So, if we look also it's a connection. Here's a blue connection in the middle, then there's not much 0.3 or 0.4 millimeter, which is enough and if you look at the next slide, you can see when it is compressed, you can see it very nicely. So, the especially on the top here's a blue, that's where the force is. So, that's the area where the gasket is, now doing is 100% function. So that means, you have
the material pressing from the top here and you have this little area here that we can see here that is having enough force to seal that and here and here and here again. So, you get four times. Four times. Four times a tiny area. It was only a little force. So, if we compare it is about 10 or 20 % of the force, which is needed for an O-ring at this area. So, that's the idea, yeah. So, this is working and we had a customer, who had a kind of O-ring solution before and his stacks were not were not gas tight and they were leaking and then we offered him this solution and then well I've been proud of it, then they called them the Eisenhuth stacks, although we did only the gasket because they were working. Okay. However, this was one story to tell but however, that's the way how to approach. If you have the right design and have the right thinking, then this will work and I mean we have always a lot of tolerances in the system. Yes. So, the one thing is a bipolar plate then the MEA
as a membrane as a pure but most challenging is gas diffusion layer and you have to compress the gas diffusion layer and with this all different tolorences and if you have a gasket which is flexible to live with this different tolerances, which are competitively quite big then this is a good solution to do this approach here. Yeah, I mean we have also in this is series talked about stacks various times and then we see I mean you know the more you stack them I mean the more and depending on what's happening between the plates, you know gaskets changes the whole characteristics of the stack, you know, and especially when it is you know in a dynamic environment, you know, we had a gentleman talking about it when it when it's in trains for example, that's like you get really hard shocked, you know, and you don't want the thing to be like what is it the musical instrument. And then you have the issue with temperature as well. Yeah. I mean if we talk in the automotive world, we have so-called cold temperature -20° C or -30° C or -40° C so, then the function must be still the same this is not the operation temperature of the stack. Yes. However, you start from this point and start slowly to get temperature higher and then the gasket must also be able to do this. Okay. So, actually I have two more very quick questions
and one thing I've always wanted is, so you have a gasket like let's say like this one here. Yeah. Okay. How do you put it in place, you know? Because, I must imagine it to be quite fiddly to go through every plate and then fiddle this thing into there. How is that done? Okay.
The one approach is that if you have integrated solution, then you have to consider a kind of area, where you can put it in. So, the gasket is laying in there and this is U-shaped area in the plate usually you do it. That's an option or if you go on the gas diffusion layer or the MEA, you have to connect them with holes. So, that the material is going through the holes and then there is a connection between the GDL or the MEA. That's the first option. The other option is again, these are and so if you have a separate gasket and I think we have also a picture on the next one, like here this could be things. So, you see these two little holes here here and here. So, you stack the system and put some needles outside and then you put one gasket after
another and then bipolar plate in between and once you're ready, you tear the things out and it is working. Yeah, okay. So, there is some extra. Yeah. So, this is also a thing and that's also an issue to do this. Yes. Okay. So, there we go so that means actually the main thing is brains design try and like design that problem out or at least somehow combat it. Okay, so Thorsten then my last question was, so I know that stacks obviously are a core element, whether it electrolysis or a fuel cell system and everyone's talking about the you know the cost of these things and obviously I think the gasket being essential to that is contribution to that. Can you tell us a little bit about you know the cost side of things? What makes gas gets expensive? Well, at the end of the day material and process cost, okay. So, we are working quite hard on this topic. However, if we look at this slide again, maybe we start at the very beginning.
So, even if we only have one piece, we can offer the customer solution, because we make a kind of picture frame and then we cut out the final design out of it. So, it's very costly and later on when we do it by the right processing technologies, like injection molding, full automatic and so on then that's the way to go here. However, it must be considered that the stack is not a topic of MEA, bipolar plate, this is also a topic of the gasket and sealing solution. So, you have to look have a look at it and to find a good solution here. Okay. So, just to mail you a little bit on that costing. So, you say when you have one that you can cut it out, that is okay, but then when you go into injection molding and so on, that is more cost effective. Well it
is definitely more cost effective. You have a kind of startup invest in order to have to have a mold and automatization technology but if you have this you can start at the very beginning at a very low cost basis. So, that's the answer for this question I mean if we have the right production technologies, then we can also make very good costly. Okay, cool. I guess that's a perfect point to end the message to all our stack manufacturers by the way, you know of course we know that there's like lots of things to be managed but I mean the gasket is very important. I know from fitting systems myself. The first thing you take a test on is
like is, is it leak proof you know. Is it leaking or not and that's always the thing. So, it's for that it's been a great pleasure, Thorsten. Unfortunately, we've come to the end of our time that you've been here to talk about this. We hope you've enjoyed this
session as much as I have. If you did, please leave us a line or a like or follow our channel. Also, you need to know on www.hyfindr.com, you can get in contact with Thorsten and many other people, who are making the hydrogen economy work. You can find the right components and services. Take a look there. Yeah and other than that I would like to say thank you again for coming.
Yes, thank you for watching. May you have a wonderful day. Okay. Thank you. Bye-bye.
2023-08-28 05:58
