Panasonic Relays for EV Chargers and Automotive Battery Management Systems: Tech Chat | Mouser
(calm music) (cheerful upbeat music) When I think about someone handling power transmission cables that operate at one kilovolt and may carry peak short circuit currents approaching 2000 amps, I imagine licensed electricians or utility line workers using specialized safety equipment. However, with the rapid adoption of EV cars, these types of powers are being handled by distracted people on their cell phones and my elderly parents. Today we'll learn about advances in electronics that are helping to keep us all safe in automotive and industrial applications.
Welcome to Tech Chat, sponsored by our friends at Mouser Electronics. On Tech Chat we meet with engineering experts to learn about the latest technical innovation that are shaping and reshaping our world. Today I'm happy to welcome Jeffery Katz, senior product manager, and Bakir Abdus-Sabur, senior product engineer at Panasonic Industry. Welcome to Tech Chat, gentlemen. So what are we gonna be talking about today? So today we're gonna be talking about Panasonic Relay technology and how it relates to EV chargers as well as automotive battery management systems.
Well that's a hot topic so I'm really excited to get started. So let's jump right in. Sounds great. So first I'd like to talk a little bit about the EV charging system and the different modes there are as well because the solution will depend on the type of electric vehicle charging station that it's being designed into. So generally the way EV chargers are categorized in are, they call it Mode One, which is generally a slow AC charging such as maybe a wall outlet in your garage. And these types of charging will pretty much take your car overnight to get a full charge out of.
Generally most of the innovation and new technology coming out today will fall into the other type of modes modest two, three, and four. So modes two and three would be considered your faster AC charging. Mode Two is specifically in cable type of charger where you'll actually see the relay in the cable. And what's unique about this application is that cable can be dropped so you need a relay in there that's very robust against shock and vibration.
And then Mode Three, which is probably the most common fast AC charging station, is a standalone charger where the relay is mounted in the charger itself. And that's going to be either single phase or three phase system depending on where it's installed. And there's different solutions depending on the type of charger there. And then the final one is called Mode Four, which is your DC Fast Charge. And for this one you're gonna be able to get a full charge in a matter of minutes, which is much more efficient for those charging their car from empty to full. However, the solution there will require a combination of both AC and DC contactors.
So this slide here shows a little bit about navigating the different standardization for electric vehicle charging and there's quite a wide web of charging standards between IEC and UL standards. Generally AC charging will fall under two different branches, whether it's IEC 61851, which is for the overall system. And then within that there's different standards for modes two and three. Also for UL in North America, generally all the standardization falls under UL 2231. And so a lot of what these standards are going to have an effect in terms of your relay performance will be dealing with things such as short circuit current ratings as well as the ability to detect if your contacts are welding right. Jeffery, it seems that these systems have the potential to exposing people to currents that they're not gonna run into typically in their home.
That's correct. So most of these charges are not gonna be designed for the home. They're likely to be designed in public places, whether it's commercial buildings or storefronts or hospitals or even on your highway. So you're gonna be dealing with much higher currents and much higher voltages than you would normally see in a residential home, But you're still having untrained professionals that are gonna be using them. That's correct.
So safety is very critical in this type of application and so is the ability to monitor and make sure that the insulation is functioning properly as well. So I mentioned before about how IEC and UL standards do have direct impact on relay design. Generally the IEC 61851 requirement will have certain requirements for the relay such as needing double or reinforced insulation, a minimum cycle load operation of 50,000 operations, and the ability to handle certain inrush currents as well. It does deviate a little bit between the different modes. So for example, Mode Three, a typical three phase system will require also a minimum contact gap of three millimeters and also have 4500 amp short circuit current capability as well, and it also has the requirement for mechanical coupling as well, which is the ability to be able to monitor the position of the contact.
That's gonna be really critical to know if there's welding involved and if the relay needs to be replaced. In Mode Two, which is your in circuit cable relay, it does have a contact gap requirement. It's not quite as large, it's only one and a half millimeters. And then there is a short circuit capacity as well which is 6000 amps squared per second.
in the UL 2331 application, this is again Mode Three for single phase systems. This is generally a North American requirement, so we're looking at UL rather than IEC in this case. Does have some short circuit capacity requirements, usually 5000 amps and it does typically require auxiliary contacts, however, sometimes it can be done externally and sometimes it can be be done in the relay.
So it's really a customer preference, although from my experience customers do prefer to be able to have that auxiliary contact within the relay because it's a simpler design, doesn't require external components such as components necessary to measure the current your voltage and also requires less complicated firmware. In this slide you can see the different styles of charging as well as the Panasonic solution. So the AC Level One charging, not gonna talk about these relays today because these relays are pretty much general use type. The amount of current in a level AC relay is not very high and so there's a wide amount of solutions available for Level One charging.
A lot of our development is focused more on the AC Level Two type of designs. And we have several generations of products for the AC Level Two, mainly the requirements for this application have has been changing over the years in particularly the ICNUL requirements. So in order to keep up with this requirement, we've had several generations of product. And also I'd like to discuss a little bit of the DC Fast Charging solution as well.
There's both an AC and a DC component to this type of charger and as of today we are focused more on the AC portion of it. Now you mentioned that the you've had to create new generations to accommodate changes in the regulations. Have those new generations also been moving up in the current capacity as these chargers become faster and faster? Correct.
So the trend in AC charging and DC charging, for that matter, is increased power to help speed up the charging and reduce timing to charge. And so we have had to increase carry current capability as well as short circuit capability for these type of chargers. So before I go into the specific series of products, I'd like to talk a little bit more in general about why Panasonic Relays are especially beneficial for the EV charging space. Historically, EV charging has been done using larger contact relays and we've been able to replace these larger contactors with our relay technology and there's several of inherent advantages to moving towards a relay. For one, they tend to be smaller in size and require less power freight.
The way that we're able to reduce the size but still carry large continuous amounts of current through the terminals is through what we call wide blade terminals. So if you look at the output terminals, they have these much wider blades that are able to dissipate the heat much better. Also, traditionally relays have not used a lot of auxiliary contacts in the designs. This is a feature that's very common in traditional contactors. However, our newest generations are starting to implement the auxiliary contact and that's gonna allow you to monitor the contact welding state. Lastly, a lot of our relays, they also use pick and hold coil operation.
So essentially once you energize the relay you can reduce the coil holding power and that's gonna alleviate some of the power consumption that's needed to keep the relay in the energized state. And it's also going to reduce the amount of heat that's introduced to your application due to oil temperature rise. This slide here shows a little bit about how auxiliary contacts work. Essentially what this means is you have your main load current going through the normally open contacts and these normally open contacts are mechanically coupled to a normally closed contact. And so if you have welding that occurs on the normally open contact, your normally closed contact isn't going to be able to close again, it's gonna remain in the open position. And so using this open position auxiliary contact, you can send a signal to your system to let it know that you have contact welding and that the relay needs to be replaced.
So let me make sure I understand that. So one side is carrying the current and the other side is, like, sending a communication signal and because it doesn't get through, because it's open, it can detect that everything is working or if it shouldn't be in the state not working. That's exactly correct. This slide here shows the different methods in which Panasonic relays can make use of our low oil holding voltage. So again, the advantage here is energy saving for the system because this is an application where relay is gonna be continuously energized and also you're gonna improve your heat dissipation because you're generating less heat from the coil.
But essentially after 100 milliseconds of the relay being turned on, you can reduce that coil holding voltage to reduce the operating power. And that can be done in a variety of ways. The first method would be to use a CR circuit. Another would be to implement the switch type method. And probably the most common way of doing this is the third example here, which is using pulse width modulation.
So generally for this we would recommend a pulse with modulation to duty ratio of 50% and to use a frequency between 20 and 100 kilohertz. So you have values here of percentages of voltage and therefore the power. What kind of a scale are we talking about that these relays were consuming during holding? So this slide here shows the different relay solutions we have for each electric vehicle charging station. In Mode Two where the relay is inside the cable, we don't have a product in production right now, however, we do have a design and samples available for a product that we'll be launching next year.
What's unique about this product, it does have the auxiliary contact and it does have the mechanical shock and vibration robustness that's required for dropping of the cable. For products that we have available today, for single phase AC charging we have three different generations of product. Originally we had the HE-S series. From there we've migrated towards the HE-R as a second generation product. And we'll be introducing the HE-A series coming this July. Here you can see our AC charging lineup by current and by contact arrangement.
So in our portfolio we actually have AC contactors that go up to 120 amps. However, for AC charging most of the applications don't tend to exceed 80 amp current. So we tend to recommend products that are similar to that range such as our 100 amp HE-A or our 90 amp HE-PV series. When it comes to contact arrangements, we do have a variety of contact arrangements and depending on whether it's a single phase or a three phase system, we have different recommendations. But generally we would recommend either a 1 form A or a 2 form A with auxiliary contact options.
So this is the first application I'd like to present our solutions for, which is Level Two AC charging for single phase. This requirement is generally a North American requirement. The chargers tend to have a range anywhere between as small as 40 amps to 80 amp chargers. So you're looking at about 9.6 to 19.2 kilowatts or so.
And auxiliary contact's generally preferred in this type application as well. So our original solution, the HE-PV Y6 series was a 1 form A solution. It required two pieces per charger and it did not have any auxiliary contact.
Since then we've released two new product. The first one is our HE-R series. So for this product it was released as a two form a plus an auxiliary contact option.
So with this solution you can replace the two pieces and just have a single piece solution. And the advantage to having a single piece solution is now you only have one coil generating heat so you're gonna reduce your coil temperature rise just simply by reducing from two pieces to one. Now our latest product, which is released in July, has a lower contact resistance compared to the original HE-PV series but it maintains the same exact size and footprint. Just we added two additional pins so we can incorporate an auxiliary contact onto it as well.
So this is our detailed spec for the original HE-PV series, which is a 90 app relay. And again, I'd like to point out this is a PCB type relay. So it's very friendly when it comes to mass production assembly. Doesn't require any wiring terminals or screw terminals traditional contactors have and also does incorporate a lower coil holding power. So your nominal power would be 1.92 watts and once energized you can reduce that to about 480 milliwatts.
This solution is our HE-A relay. This is our newest solution released in July. And again, as I mentioned, we increased the power of this relay so it's actually capable of handling 100 amps continuous current. We added an auxiliary contact to it as well.
And the short circuit current rating for this has been increased as well so now it is 5000 amp. And this is really necessary to keep up with the latest UL standards for short circuit current rating in this application. Again it still incorporates the low coil holding power.
So this one has a maximum coil holding power of 310 milliwatts and it still has the same footprint as the HE-Y 6 but with the additional terminals for the auxiliary contact. Well, it's really impressive that you guys continue to drive up the current handling capacity of it. But then the packages themselves are getting smaller. You know, you've mentioned temperature as being a challenge.
You know, all those things are kind of fighting against each other so the fact that you're able to optimize all of them is pretty impressive. So this is the inside of the construction of our HE-A relay a little bit up close. So you can see the main contacts are, actually, it's a twin contact which you can find on the bottom of the relay.
It has basically two movable arms that are connected to each other and that creates your normally open contact. But what you'll also see is that if you follow the hinge spring upwards, you'll actually see that on the top surface of the relay is the auxiliary contact, which obviously is much smaller in size 'cause it's only connecting signal across it. However it is mechanically linked and that's how you get this mirror contact structure which allows you to detect the welding of the normally open contacts. Well, that's pretty neat to get to see inside these, it's something that I've never been exposed to on the technology side.
So there's a lot of complex mechanical and intellectual engineering going on inside. This slide shows our introduction of our HE-R relay. Now this relay comes in two different types, actually. For now, just keeping with the single phase EV charger, we recommend the 2 form A with auxiliary contact for this application.
This has a continuous current load of 80 amps across the contacts. Again, this has two normally open contacts, so you would only require one relay, and it does have the optional auxiliary contact as well. The nominal operating power for this, once you reduce the coil power to about 35% of the nominal voltage becomes 490 milliwatts. The next application I'd like to discuss is the 3-phase AC charging application.
So for this one you're now required to cut off three lines plus neutral, which is going to require four separate contacts to do it. Generally the current for these types of chargers doesn't go as high as a single phase charger. Looking at typically the maximum somewhere around 50 amps. But could be as low as 32 amps as well for contact. So our original solution for this type of charger was our HE-S relay and this was a 2 form A solution with an auxiliary contact option.
However, since the release of this relay, the need for faster charging and higher current and higher short circuit current requirements have increased and so we've introduced what is called our HE-R series. Before, earlier we looked at this series as a solution for single phase. However we also released a 4 form A version with an auxiliary contact and that's used specifically for three phase charging.
And so this has all the contacts in one relay, so you're reducing from two pieces to one piece. And it also has higher carry current capability and it also has a higher short circuit current rating as well. One thing I'd like to mention is just the difference in structure between the 4a1b and the 2a1b. These relays essentially are the same size, we've just increased the number of contacts for the 4a1b. So if you were to look at the data sheet, you will notice that the 4a1b does not have as much current capability as the 2a1b. However, because the three phase system doesn't require as much current as compared to the single phase system, it actually works out perfect for each application.
And the three phase here is, while the individual currents are gonna be lower, aren't you still passing as much or even more power through the relay? Yes, in three phase systems you are actually drawing more power compared to the single phase. However you've got that spread across four different contacts. So you actually have less carry current per contact than you would compared to the 2 form A version for single phase. So as a follow on to that, I would say that that you didn't have to deal with more heat generated in this small package so making that design challenge for you guys at Panasonic even more difficult.
That's right. And also I might also note the switching voltage for the single phase versus the three phase is also going to be different. And so the relay is designed to withstand the switching voltage that's necessary for three phase systems. So here's the HE-R 4a1b relay, a little bit more detail. It does have a 50 amp maximum carry current rating and it does have a nominal coil holding power of 490 milliwatts. Again, it's a PCB solution, so very friendly for mass production, and it does satisfy the short circuit current rating as dictated by IEC, 3000 amp.
So here's the last mechanical relay solution that I wanted to present today, which is the DC Fast Charge application. Now it requires several different types of contactors. It requires a DC contactor, it requires AC contactor, and unfortunately we don't have a solution for either of these.
However, we do have a solution as a pre-charge on the AC contactor side. So generally the AC contactors go up anywhere between 400 to 690 vols AC and about 367 amps or so. This exceeds the switching capability of our relays.
However, we can use some of our relays such as our HE-R or the HE-A that I presented earlier as a solution to, as a pre-charge for the AC contactors. So essentially this is protecting the AC contactor and extending the life of that contactor. Up until this point we've been talking about our mechanical relay solutions and I would like to switch gears a little bit and ask my colleague to talk a little bit more about our PhotoMOS solutions. This could also be used in EV charging, particularly DC Fast harging, as well as in a large array of automotive applications, which include battery management systems.
Thank you Jeffery, for the introduction. My name is Bakir Sabur and I'm our senior product engineer for our PhotoMOS devices. So here at Panasonic we have two types of devices. We have our mechanical relays, which are contact types, and we have our solid state switching devices or otherwise known as our PhotoMOS.
And these are products without physical moving contacts. So some key advantages when using our PhotoMOS. Very long, wide, small size, high contact reliability, high switching speeds, and also no sound noise. We have a wide variety of different sizing options for these particular devices.
Our TSON being our smallest device all the way up to our AQZ, which are more higher capacity type of devices. Now for the applications that we'll be discussing today, we have a smaller portfolio which I'll cover in a couple of slides. And it is important to note that these devices can also control both AC and DC loads. So moving on to the comparison between electromechanical relays and our PhotoMOS, just to highlight some key differences. In terms of the output configuration, mechanical relays are a lot broader in terms of its different footprint. For example, 1 form A, 1 form B, 1 form Cs.
Our semiconductor products are limited at the moment, but we are looking to expand into different contact arrangements. Output current is not terrible. Approximately 10 amps is the highest we can switch for our semiconductor devices. Output voltages are high. Quiet operating sound noise due to not having any internal moving components.
Long contact life, high contact reliability. Good for switching smaller little currents and also switching a very high switching space. So these are some inherent advantages when adopting the semiconductor technology over the traditional electromechanical release.
So our value proposition for our PhotoMOS devices is that we are able to propose the best solutions through our wide variety of different options and also technical consulting using our spec reviews, which I'll get into and do a couple of slides after I review our automotive PhotoMOS lineups. Also very flexible with custom development. So we offer a number of different custom part numbers for wide variety of different requests. So please do not shy away if you don't see any particular products on our current portfolio. We may be able to provide you with a custom solution tailored specifically to your needs. And we also have a very special quality control and reliability test for automotive, using different types of special materials from our assembly, having dedicated production lines, and also passing AEC stress tests.
Now as I mentioned, we have a very wide portfolio for our PhotoMOS products. Our products specifically tailored to the automotive grade are a little bit more niche and a smaller sect from our entire portfolio. So we have a wide variety of different applications in the EV or automotive market ranging from battery monitoring systems for battery monitoring, leakage detection, with the inverter side for switching DC link discharge and in the battery disconnect unit for any type of relay welding detection and specifically an EV chargers leakage detection application.
So without further ado, I'll get into some of our products and also specific applications within this market. So for DC Fast Charging, we recommend our PhotoMOS for installation leakage detection. Simply how this works is if our PhotoMOS is turned on and there is leakage passing through the device, it will alert that there has been some leakage within the system. For this specific application, we recommend our HE High Voltage Type.
This part number is our AQV258H5. This device is pretty unique as it has a removal of the fifth pin. This increases the distance between the output terminals, further increasing the isolation voltage capabilities.
So this part is a 1500 volt part. Load current of about 0.02 amps. And an isolation voltage of 5,000 volts. Again, the typical applications for this can be used in battery monitoring systems and specifically for leakage detection within these EV or DC Fast Charge devices. So that's interesting there.
So this is a DIP 6 package where you've removed one of the terminals specifically for improving the performance in these applications. Yes, that is correct. For our next slide here, again, the first slides were kind of covering our applications in the DC Fast Charging applications, but there's also similar applications within the automotive or any industrial mobility type of devices.
So similar to the last slide, we also recommend our PhotoMOS for leakage detection in these areas. Now you may notice if you look at the part numbers on the bottom left, they have a designation at the end, C*9. This indicates that this is a custom part. So currently all of our PhotoMOS for automotive applications are custom parts.
None of them are standardized just because they're tailored specifically to each automotive application. So again, we recommend our PhotoMOS for leakage detection, if any insulation is deteriorated in the section current passes when the relay is on and that will signal an alarm output. So for this specific application, we offer two types of devices, one at 900 volt. If you require higher voltages, we also offer 1500 volts. So could you elaborate a little bit on the customization? What would a customer need to bring to you to allow you to customize for their solution? Yes, so I'll cover this a little bit in more detail in the later slides within our spec review process, but just to briefly mention, safety and reliability are very important when designing, again, our PhotoMOS within these automotive applications.
So there's a couple of things that go into it to ensure that the customer is operating these devices properly, including de-rating voltage, so ensuring that you're not overdriving the device, for example. So when looking at leakage detection and where our PhotoMOS provides value in compared to different solutions in the market such as Discrete or Reed Relay, as you can see, our PhotoMOS provides a very simple circuit. So there are two devices. You're able to save space. And there's a also a singular guaranteed spec.
As we're looking at discreet solution, you're using multiple components. So you may be using a driver along with two other MOSFETs. So you have many parts within Discrete solution system. Six pieces total versus the PhotoMOS which will be only two. And this also takes up a larger size, so approximately 140% larger versus the PhotoMOS. And when using traditional Reed Relays, these are inherently a lot larger in size because they are mechanical relays.
So approximately 198% increase versus our PhotoMOS. Along with Reed Relays, you have very limited contact life, low switching speeds, and low contact reliability. So overall our PhotoMOS proves to be very advantageous to use in design in within these applications. We also offer PhotoMOS for BDU. I mentioned in the earlier slides about the relay welding detection. So some of the benefits of using our PhotoMOS in these devices, you're also able to save space.
We can support up to 1500 volt battery packs. And due to not having any internal moving components, there's no welding in the contacts. And again, similar lineup as the previous slide, we offer our AQV219, which is a 900 volt part, as well as our AQV258, which is a 1500 volt part. So we also have PhotoMOS for Inverter applications. So you may notice a common theme with the advantage of using our PhotoMOS versus other solutions in the market.
For example, we have a lot simpler circuit within this design. Using a singular PhotoMOS there's no need for any additional power supply lines nor any capacitor Zener resistors. So all in all, you're able to also save space due to reducing the amount of components that needed to be used. And we're also able to support up to 900 volt battery packs.
Now you may notice that the part listed below is rated at 1200 volts and the reason why there's a difference between the 1200 volts and 900 volts alludes to what I was talking about earlier with the de-rating. So we typically recommend de-rating the voltages when using these devices to ensure safety and reliability, to ensure that you're not overdriving the part numbers, not overdriving the PhotoMOS. Next we also offer our PhotoMOS for battery monitoring systems. Here we have our AQV219, which is a 900 volt part, and also our AQV258, which is a 1500 volt part. The advantages of our PhotoMOS within these applications ensure a healthy battery life.
So we have high voltage, very small size, long life, and higher reliability to be designed into these application. So lastly, on the list of applications, we have a PhotoMOS for LiDAR and fan control. Again, using our PhotoMOS, you're able to simplify the circuit. No need for any additional power supply lines or capacitor resistors, and ultimately you're able to save space reducing the overall footprint and board space needed to design these products in. For this specific application, we recommend slightly different products that we've been seeing here.
This will be our AQY, which is our SOP four pin package. Slightly smaller than the AQVs, the DIP sx pin packages that we've been mentioning in the previous slides. And this is also our AQW, which is a SOP eight pin, a dual channel PhotoMOS device, which is a 2 form A, also rated at 60 volts and 350 milliamps.
So here shows our complete product lineup for our automotive PhotoMOS. Now we're continuously seeking new development and improving our product lines. This includes being able to drive higher voltages, especially in the future. Because we do have to de-rate the products we can't operate at the maximum value so we are pushing the bounds of technology in further developing products with higher voltages so we're able to continuously improve as the customer demands are increasing. So as you can see, the absolute maximum ratings are listed above. For example, we have 600 volts, 900 volts, and 1500 volts.
Actual recommended usage conditions will be at 400 volts for the first product, 600 volt for the 900 volt type, and 1000 volts for the 1500 volt type. And this will ensure a good, or this is our recommended de-rating to take into consideration the product reliability and the overall life cycle for optimal usage. This here just goes into a little bit more of the electrical characteristics of these specific devices.
All of these values can be found in our data sheet and it goes over, for example, LED operating current on a resistance, switching speeds and again, these can all be found within the product data sheet. So this here is our Spec review, which will be the most important part of designing in our automotive PhotoMOS. Safety and reliability is Panasonic's number one concern.
So we always ensure that the customer to fill the Spec review out. That way we can ensure that there is proper usage and operating conditions when using our device. So overall, our PhotoMOS can be used in a wide variety of different automotive applications and provide unique advantages when compared to different mechanical relay solutions in the market.
If you have any further questions, we will love to be in contact. So please reach out and we can talk about some different applications or customers that you may be interested in showing our automotive PhotoMOS to. Excellent. Well that was definitely an interesting technology that I'm not familiar with, so thank you for that, Bakir.
Thank you guys for being here today. That was a really great introduction to the technologies that are kind of underlying advances in the EV charging industry. And so I was excited to learn these things. I think our audience will be too. Thank you. I did as well. And as we end today's Tech Chat, we wanna thank our sponsor, Mouser Electronics.
If you're looking to purchase any of these great Panasonic Industry products, please head over to mouser.com to help them continue to support educational presentations like this one. And join us again next time on Tech Chat where we chat with the leading technical experts like Jeffery and Bakir from industry leading companies like Panasonic Industry who are changing our world every day. (gentle music)
2024-10-04 00:23
