Tech Talk - Cell Voltage Monitoring Systems for Fuel Cells - Hydrogen Technology - Schuster Hyfindr
Hello, my name is Steven. Welcome to Hyfindr Tech Talks. Today, we have a topic called CVM and when I was a project manager many years ago, we had a huge fight. Whether we need CVM or what are we going to do without CVM. And so I am particularly happy that we'll be talking about that today. It stands for Cell Voltage Monitoring and we have an expert to talk about this today. It's a guy who basically has been in electrochemistry since high school. He
has a doctors degree in that and now works for Smart Testsolutions. So I'm very pleased to welcome Markus Schuster. Hello, Markus. Hello Steven, great to be here today. Perfect. Thank you. So I see you didn't come alone. You brought some components with you. What do you have here?
So first of all, I brought some Cell Voltage Monitoring devices with me to take a look on it. So I got on one side a modular device for research and development. We have a single board solution that's mainly for serious applications. And we have the second component that is important in that context as well. Cell Voltage Pickup. Cell Voltage Pickup. Okay. Because here is monitoring. Yes, here is getting the voltages out of the
bipolar plates. Okay. So we have Cell Voltage Monitoring and Cell Voltage Pickup? Okay. So let's take it one by one. What is Cell Voltage Monitoring? So a CVM system is first of all, a monitoring device that measures individual cell voltages or cell group voltages within a bipolar electrochemical stack, it can be a fuel cell or an electrolyzer. Okay. I see you have this mock up here, if I may take that. Which essentially this is sort of like a set of cells that you have here. And when you say cell voltage monitoring,
where would you be monitoring here from where to where? So the monitoring is done within the electronic component. Okay. Yeah, but you have to get the voltages out of the stack. So measurement or what would you call that? We call it cell voltage pickup. Pickup that is okay. All right. Exactly. And if you see a mock up of an electrochemical stack. Yes, it's a fuel cell. You'll see here the cell voltage pickup component that is here. Yeah. So in reality, it looks like this. Yes. And we have here the pinholes. And
these pinholes are the interface that we use for getting the voltages out. So we stick the cell voltage pickup component inside the pinholes so that goes in there. Yeah. Okay. And every contact has a directly electrical connection to the bipolar plate.
Okay. We measured the potential of every bipolar plate. Yes. And our cell voltage monitoring devices get the data and calculate the differential voltages between two neighbored pinholes. Okay. And that is the cell voltage. Okay. So that means we have a cell at the bordering. Every cell is the bipolar plate. And that's
exactly where you pick up that voltage and essentially measure that between. Ok. Now I've used the word measurement. Is cell voltage measurement the same thing as cell voltage monitoring? Correct. Okay. CVM is a sensor. It has no influence on ICU control tasks. We are just a sensor providing data. Okay. So we've seen this is the.. So we'll talk about pickup in a minute, but just take us a little bit deeper with the monitoring part.
So say we have now the electric potential, you call it, between the two cells. What how does the monitoring part work? What how does that go? The monitoring part collects all data. Yeah. Normally fully parallel because for our customer, it's very interesting to see hundreds of voltages. Yes. Fully parallel in real time. Yeah.
That's an important topic. And the data summary is done within the CVM systems. Okay. So when you say your customers want to see this, so who wants to see the result of this? Where are the typical applications for cell voltage measurement? First of all, wherever you need an bipolar electrochemical stack. Okay. Fuel cells, electrolyzers,
batteries. A CVM can be needed, sometimes is required and therefore all markets are widespread. So we have automotive customers. We have customers in the aviation field, in the train field, in the in the truck field, in the ship field. So everywhere. But as well in the industry for Electrolyzers, that's a growing business at the moment because it makes no sense having fuel cell driven cars. Yeah, but no way to get the hydrogen. Okay. So that's why you need electrolyzers to make the hydrogen. Yeah. Okay. So I think we'll let's go into this one more because I think you've already said whether you need that, I would like to understand a little bit more. So, cell voltage monitoring,
again. We said pick up the voltage and then, and then what happens? You know what are the components that actually lead to us having a measurement result. So here I have a slide where we can have a short look. So, first of all,
you have the cell voltage monitoring device. It's the board, it's the same. So that's this, that's okay. And this has on it. I see several ICs and okay, okay. Yeah. This is a board with 170 channels. So here you can measure 170 cell voltages. So 170 cell stack could be connected to this or battery cells. Okay. Yeah, exactly. So this
is the, the core component, within the system. Then you have here the cell voltage pick up unit. So yeah, here is a reality part of this. So this connects to the actual cell and this transmits the current and then this one this does this stick right on here? This is the connection to the right so to the cell voltage monitoring board and it's just.. okay there you go. And you have to connect all the data. So, if I had a stack, I just attach this on the stack and then. Okay, so this can be near the. Okay. Does it matter how far, how long the distances can be. It could be five centimeters. It can be five meters.
Oh really. Okay. No matter here. So but when you just have these components, you need to fix them. Yeah. Close to the stack, then. That's the mechanical framework that we need as well to mount the components on the stack or at the side of the stack. Mm hmm. And last but not least, we have a harness. Yes. For power supply of the electronic device and for getting the data out. Okay. So this will, this will.. What kind of power does this need? How much power would this consume and what voltages
are we talking about? That means we are working here in the normal 12 volt or 24 volt grids. Okay. Inside test stands, inside vehicles. Okay. Very good. Okay. So that means essentially you connect all the cells with this. You have several of these. And then I see here, Yeah, this would be your connection to the OK. Yeah. I must say here,
so there are two philosophies. Yes. So you can take the power for the CVM out of the stack. Yes. Or you can use an external power supply. Okay. So our approach is an external power supply because we want to see the cell voltages directly when the system is switched on. Okay. Other solutions that use the stack power is that they can stop measuring when the stack is on load. Yeah, okay. That's true. And I mean, I don't know the nitty gritty of it, but I would assume that then they are also part of the load themselves.
You know, if you are that okay. So okay. So we've seen the the different components. And so how does then the result of this look? So the result within the CVM is we call it bar graphs. Okay. All right. So here I have some examples that may happen or that may not happen. So you have the normal operation. That means all bars are.. have almost the same. Ok. They are a bit gitteringjittering. Ok. So like if this were our cell set up again you'll be measuring
all of them.. and then they are all running at a nice same voltage. Ok. And everyone's happy. Everybody's happy. Yeah. Exactly. So, so in reality it's a little bit different. Ok. At the borders of the stack, the voltages are a little bit lower than in the middle. Why is that? Oh, that's a good question. Okay. Well okay. All right. Thats
a secret of our customers. But that is the consumption with the gases in the fuel cell. Right. Okay. Yeah. There is an circulation there. Okay. Understood. Okay. But because they have or if they have cell voltage and they can see that. If they don't, they can't see that? Exactly. Okay. So okay, so here you see, you have.. this is a normal operation. Okay. So, in this way, what we see here is an important security aspect of a CVM. When you have a loss in connection. Yeah. For example, with one cable. Ok,
Yeah. Then you have a kind of cable break event. Okay. The same is demonstrating this. Okay here then the bus are missing. Okay so this would be if I, if I pull this one out, you know basically okay you have to it's a little bit hard. But okay. But obviously that's trying to prevent that.
We need to fix it on the stack. Yeah I can see it's really.. it's almost hard for me to get this off. Yeah but yeah. So that's okay. So that would.. Ok. Then this would goes out then. Okay. The bus to disappear. Yeah. Okay. Yeah. As well. We can detect critical operation tasks within the fuel cell stack. What no fuel cell likes is a negative cell voltage. Okay. So and this can be detected with a voltage monitoring device. So when you just measure the stack
voltage. Yeah. And one cell is negative. Yeah. That it's very, very difficult to see this one negative cell. It's impossible, isn't it. Almost impossible. Imagine you don't know what's this. Yeah. With this CVM. Yeah. You can detect there is a cell with a negative voltage and you can locate where it is as well. So essentially, each bar here represents one of these cells. So, and what we have here.. That's another display of, the measurement data. So on the one hand we have the bars and we have tables. And in the tables we can give limit values.
If a measured value is above or below a limit, then it's marked red. Okay. So that means okay. And so now we have talked about seeing this. I know you also have, I think you brought a little video how this is in action. Can we see that one? Maybe. That's probably going to help our users. Yeah. Okay. Yeah. So. Okay, this is. This is running. So this, this is. This is showing all the cells running at 0.5 volts. More or less. Exactly. That's an example for a stack on full load. Okay.
Okay. So exactly. So it's going on that way. Okay. And I see the little bit of jitter here, you see. Yes. That's normal that you see a little bit jittering in the cells. And you see the minimum voltage, the maximum voltage, the average voltage and the stack total voltage in this field that can be calculated by the CVM as well. Okay. And I saw it. Oh yeah. From time to time you see like this little one that jumps up. Is that normal when you, when you're measuring as well?
It's normal. Yes. That, that comes from, EMC disturbances on, the stack on the system. There we can see the table again with all the different values. Okay. So just before we get into the interpretation, again, tell me a little bit about the pickup aspect, because I know, you know, we saw the one graph where we had, if I may, we had this thing that, you know, we had an interruption here.
I know that there are different techniques to actually touch or get to the cell to measure it. First of all, we must say that we consider the cell voltage monitoring device is kind of a standard device. Okay. So the cell voltage pickup is a completely customer individual design. You have lots of different designs. This represents our.. so we have some types of bipolar plate interfaces. So this is a kind of pinhole. Yes. We have pockets. It’s a solution
like this. It's not a hole. It's just a flat version. They're laying in the pockets. Then the contacts are laying on the stack. And I have no example for but the third group is a flag that comes out of the. So if we can have a look at here. So you have pinhole. So pinhole is like this one. Yeah. Okay. Then we have pockets. And the pocket solution was this one that we saw here. So essentially we see these, okay. They're literally kind of laying in there, like laying between the cells and
they must be pressed on. Oh, they must be pressed to get the forces. Okay. Right. The context, will remain in shock and vibration conditions. So that's the pocket. Okay. And then this is the flag. Okay. Yeah. Where you can stick it on top. Okay. And this is also a.. What is this one? It’s also
pinhole or? This is also a pinhole. A pinhole geometry. We can take one out. You can see that. Okay. And that's kind of grabbing. So such designs we can have wired designs like here and we can have flex cut designs. Flex cut cards when we do not have so much space. Then we need flex cutscards. And here this means the cell pitch is different to the measurement CVM pitch. Okay, okay. Understood. So that means here we have essentially, let me say the hardware aspect of it that you know. How do I contact the cell so that it does not,
you know, that contact doesn't break because I want a continuous measurement. Now, Markus, I know you've been in this industry for a while. So why, why should one do this? Because like I said, we had a huge fight, you know, because this costs extra. I know if you are, let me say a manufacturer of cell voltage monitoring systems, I guess I would know your position if one needed. But at least like, why does it make sense? And I know that, for example, I think the Toyota models, the first ones of.. They all had cell
voltage monitoring. And then I know some other manufacturers brought out their vehicles without cell voltage monitoring. So can you tell us a little bit about the pros and cons of, you know, one having this and what not? So first of all, I must agree, a cell voltage monitoring system costs extra money. Yes, that's true. Yeah. But you get benefits from this system because you can have a deep look inside the stack. Yes. And you see, we call it the state of health
is whether everything is fine with your stack or not. You'll see operation states that are critical. Okay. But sorry if I interrupt you there. But if I you know, let's say a vehicle or a system has been running for, you know, 2000 hours, you know, and there's a driver driving along the highway and then there's a cell voltage monitoring running. And what does he.. What does the driver benefit from that? You know. Okay. If that tells me like cell 27 of 100 that you have under but is just losing voltage. What can the driver do? The driver shouldn't see the cell voltage monitoring just the control unit.
Okay. Let's see the data. And then what happens? What do you do? As a for example, I can give you an example here. So for example, when you have a fuel cell car. Yeah. And you, you let it outside is in winter night, cold -20 degrees. And in the morning you leave
your house and then you start the car and then the problem begins when you do not have a CVM. Because when the whole system is frozen it may happen that the hydrogen channels. Yes. That the gas can reach the the electrodes. Okay. Is blocked by a frozen water droplet.
All right. Right. And then this cell is not supported with hydrogen. And when you start the engine and start driving, the fuel cell gets the power to the car. Yeah. But when this cell has no hydrogen the electrochemistry is looking for another reaction partner. Yeah. Okay. That's obviously detrimental to that particular cell. And that are irreversible processes that destroy the cell. Okay, so what would the cell voltage monitoring help in this case? To just start the system or what? No. The cell voltage
monitoring system is detecting. Oh stop. I have one or more negative cell voltages, so it's not allowed to get to the fuel cell stack under load. Okay. And as in the battery in the electric cars, there's the heating elements around the
stack. Then you switch on the heater. Yeah. And you start driving with your battery. Okay. And then you warm up the stack. Warm up the stack. Get it all right. And then go gently on it. Okay. So it's essentially part of the wellness program of the stack. Right. Okay. So. I know that this is a good example. But I see that there's been lots of development also with AI and all these kind of things and predictive this and that. I mean,
because I have heard these arguments as well would say, okay, I can learn and then I don't need my cell voltage monitoring again. So can you give us a little bit of an outlook how you see the whole topic of cell voltage monitoring as well? You've been in it for a while, and I know that in the development space, surely it will be able to give us a general outlook for me. First of all, Smart Testsolutions is in this field since more than 30 years. All right. So and let me just tell what our customers are telling us, since 30 years. More
than 30 years. Oh, yes. At the beginning, research and development, we want to to start to learn, to know our stack. Then we need a cvm CVM later on. We don't know exactly anymore. But these customers exactly. They are still using cell volatage monitoring systems. Yeah. Okay. Yeah. But for the outlook. The CVM was a long time just a research and development sensor. It was nothing more. It's therefore we have modular designs with a flexible number of channels. Yeah, but we see in the last years that we get into small,
serious applications. We have more projects that are dedicated to serious applications and that means new requirements on the system. But we see this this progress. Okay. So probably also your costs coming down, the system's getting probably cheaper. Yeah. And that's making it more attractive to have that in. And I guess from the
engineer's perspective, you knowing what's going on in the system is always an advantage. And plus, I mean, this is used in fuel cell and hydrogen and electrolyzer systems, but also in battery systems. And so this is also of relevance, I guess. Yeah. So I guess there's a big future for
all of this. Thank you very much, Markus, for explaining us and taking us into this world of cell voltage monitoring. I hope you have enjoyed this and have learned as much as I have about monitoring and pickup and measurement and all these little things. And jitter. If you liked it, then please give us a like subscribe to the channel. And actually one thing, if you want to find more stuff like this or anything related to the hydrogen economy go on Hyfindr.com, you can find the products of Smart Testsolutions there and also get in touch with people like Markus. And yeah, hopefully you can find great solutions for the hydrogen economy.
Thank you very much for watching and enjoy another video on this channel. Have a lovely day. Thank you. Thank you, Steven.
2024-04-04 21:23
