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 work

s  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 sec

ond 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. Ex

actly. 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 mea

sured 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 ve

ry 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 th

ink  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 th

e 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 w

ell 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 essen

tially 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 ca

n 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 ca

n 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 thi

nk 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 yo

u 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 interpr

etation, 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 p

ocket 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  pi

nhole 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 on

es 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 losin

g 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 syst

em 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 irreve

rsible 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 t

hen 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 lit

tle 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 o

ur 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 appli

cations 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 gues

s.  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.