- For decades, automotive accessories have been powered by a 12-volt electrical system. Now, as an ever-growing list of accessories demand more power, automakers are beginning to shift to 48-volt architectures.
- Replacing 12-volt systems with 48-volt systems increases efficiency, reduces waste heat, and allows wiring harnesses to be shorter and lighter.
- The transition to 48 V applies to all vehicles, but it’s especially relevant to EVs, because increasing efficiency and reducing weight translates to longer range. Furthermore, certain accessories that are powered by belts or by waste heat in ICE vehicles are powered by electricity in EVs, so more electrical power is required.
- The transition to 48 V is proceeding in concert with a transition from centralized architectures to zonal architectures, which allow designers to reduce the number of wiring harnesses and electronic control units (ECUs) needed in a vehicle.
Q&A with TE Connectivity’s Helio Wu and Pradeep Moorthy
A vehicle has always been more than an engine and a set of wheels. Lights, windshield wipers, heaters—these have been essential equipment since the days of hood ornaments, and over the years more and more accessories have come to be seen as indispensable. Power windows, power locks, cruise control, heated/cooled seats, and now infotainment systems and Advanced Driver Assistance Systems—the list grows longer every year. And of course, accessories include not only gadgets for the driver’s comfort, but also systems essential to the operation of the vehicle (e.g. in the old days, alternators and water pumps, nowadays battery management systems).
For decades, electrically-operated accessories have been powered by a 12-volt electrical system, and components, connectors and wiring have all been designed to operate on 12 volts. In recent years, as power demands have increased, automakers have been moving towards 48-volt systems. This is a trend that applies to all types of vehicles, but as TE Connectivity’s Product Manager Helio Wu and Senior Manager of Product Management Pradeep Moorthy explained to Charged, there are several reasons why the transition to EVs is accelerating the transition to 48 volts.
Charged: Why are automotive manufacturers shifting to 48-volt architectures? What are the advantages?
Helio Wu: The major driver is that power requirements keep increasing, and because of the higher power requirement, the current level keeps increasing as well. The higher current level requires wires with larger diameters, and that is creating a substantial challenge in wiring harness routing. Increasing voltage to 48 volts can reduce the electrical current by three quarters, assuming the same power requirement, and thus we can save a lot in both the wiring harness weight and cost.
Charged: If the power remains the same, then the wires can be smaller and lighter. But at the same time, we’re asking for more power. So, is there generally a net reduction in the size and weight of the wiring harness?
Helio Wu: Yes. The power requirement is increasing, but it doesn’t increase by four times, so overall, we still can expect a lot of weight reduction and cost savings from this transition. Meanwhile, this transition will take place along with a transition to a zonal architecture. The zonal architecture itself can optimize the overall electric architecture in the vehicle and shorten the wiring harness length, because previously automakers used a centralized star topology. Now it’s decentralized, and the power equipment is managed within the zones, so the total length is going to be reduced.
Increasing voltage to 48 volts can reduce the electrical current by three quarters. Power requirements are increasing, but they don’t increase by four times, so overall, we can expect a lot of weight reduction and cost savings from the transition.
Charged: In a recent video from Rivian, their engineers explained that they were able to reduce the number of controllers and the vehicle weight significantly, mainly because of the move to a zonal architecture.
Pradeep Moorthy: I remember watching some videos recently about the things that Rivian’s doing in that space. What we are doing there is consolidating multiple controllers into one in each of the different zones of the vehicle, and we are packaging a lot more of the computing capabilities that were in multiple controllers into one—this drives up the power requirements for those controllers, which justifies the switch to 48-volt, so they definitely are correlated.
Charged: So the shift to 48-volt kind of enables the shift to the zonal architecture?
Pradeep Moorthy: Absolutely.
Charged: The transition to 48-volt is taking place across all types of vehicles, but tell us about how the rise of electric vehicles is specifically driving the move.
Pradeep Moorthy: The switch to 48-volt is not just for electric vehicles. The benefits are shared regardless of what the propulsion mechanism is. On the EV side, though, there are a couple of specific things. First, every kilogram you can shave off the weight of the vehicle is more valuable in an EV from a range standpoint, so EVs have more to gain from switching to 48-volt. Second, younger OEMs that focus on EVs are more open to step changes in their architectures. With the switch to 48-volt, you do need to make a significant change because most devices throughout the vehicle need to be updated to work on 48 V rather than on 12 V. From an implementation standpoint, the way OEMs are structured today, the EV-specific teams are better positioned to make that jump.
Helio Wu: There’s also another reason why we see EVs leading this transition. An internal combustion engine not only drives the vehicle, but also provides power to many auxiliary applications. If we talk about EVs, all those applications traditionally driven by belts now become electric-driven, and they are power-hungry devices. And the more power-hungry it is, the more benefit we can expect if that application can be converted to 48-volt.
An ICE not only drives the vehicle, but also provides power to many auxiliary applications. In an EV all those applications traditionally driven by belts now become electric-driven, and they are power-hungry devices.
Charged: Obviously, OEMs that are more innovative, more forward-looking, are moving faster with electrification. Are those also the ones that are more interested in 48-volt?
Pradeep Moorthy: Apart from an innovative mindset, organizational will to implement disruptive changes is necessary. A few OEMs leading the way on electrification are better structured in that regard. But that’s not to say that the other OEMs are not interested—they are looking at ways to switch to 48-volt as well. The steps taken to switch and the timing will likely be different, though.
Charged: What are some specific components we find in EVs that are driving the move to 48-volt systems?
Helio Wu: I can give you an example. Earlier this year I had a conversation with a customer engineer and he told me that for him, the biggest advantage from 48-volt is thermal management. In his next-generation vehicle, we have so many electronic components running at high power that if we do not increase the voltage level, the heat generation and the temperature would rise to a level that is unmanageable.
Switching to 48-volt reduces the energy dissipation and the heat dissipation, so it can help reduce the temperature of those modules within the system. And it helps a lot in guaranteeing the longevity of those devices, making sure they can work properly through the vehicle life. We talk a lot about the wiring harness weight and cost savings, but reduced heat generation is another major benefit that the OEMs can get from this transition.
Charged: Tell us more about how a 48-volt system can improve energy efficiency, something very important for EVs.
Helio Wu: It’s simple physics. When we talk about the energy loss dissipation in the wires, it’s W = I2 * R, right? Suppose we use the same wire, same wiring resistance. If we reduce the current level to 1/4 of the previous value, that means the energy dissipation can be reduced to 1/16. That’s a lot of reduction, and therefore we improve the energy efficiency and the power delivery efficiency in the vehicle system. This is a direct benefit. Indirect benefits include weight reduction, so we can have a longer range.
Charged: Both 12 V and 48 V systems can coexist within the same vehicle, but will 12 V eventually be phased out?
Helio Wu: I believe that 12-volt and 48-volt will coexist for a period, maybe three years, maybe five years. Not everybody will be ready for 48-volt. That’s just a reality. Going forward, gradually suppliers’ readiness will be improved, and then eventually, I believe 12 V will be eliminated from the current low-voltage system, and 48 V will be the norm.
Charged: That sounds like a pretty quick transition. Within five years, you say, everything’s going to be 48-volt?
Helio Wu: That’s my hope, because we believe it will not only benefit the OEMs, but also provide more advanced functions to the end consumer so we can have more exciting vehicles.
We believe that 12-volt and 48-volt will coexist for a period, maybe five years. Gradually suppliers’ readiness will be improved, and then 48 V will be the norm.
Charged: Your company is all about the connectors, so tell us more about the role that connectors play in enabling the 48-volt architecture.
Pradeep Moorthy: From a connectivity standpoint, it’s primarily about safety, when you go from 12 V up to 48 V. With the higher voltage, we want to make sure that there is sufficient insulation between circuits and there are safety mechanisms in the vehicle architecture to ensure that people working on their vehicles are protected as well. What we are doing today is looking at our existing portfolio to see which products are already safe to be used in 48-volt applications. We are also building a whole new portfolio of connectors that are designed specifically for use in 48-volt applications.
Charged: Will this eventually mean redesigning your product lineup?
Pradeep Moorthy: Not necessarily all of it. I think it will be more of an evolution. The key things here are what we call creepage and clearance, which refers to the distance between adjacent circuits to provide sufficient insulation and preventing any kind of arcing or current creepage. Because of how they were designed, higher-power connectors for 12 V happen to be safe for 48 V already, so there is a significant part of our portfolio that can be used in 48-volt applications without any changes. In the smaller end of our portfolio, where we have very low-power and signal applications today, those connectors tend to be optimized for 12 V applications, so they’re not ready to be used in 48 V applications. In those spaces we are developing new products to fill out the portfolio.
Charged: Some of these connectors are just powering devices, some of them are sending data, and some are doing both, right?
Pradeep Moorthy: Yes, that’s right. Helio and I are both part of the Signal and Power Connectivity Group within TE’s automotive business, and that covers all our products up to 48 volts as an upper limit. The products within this portfolio historically were tailored specifically for low-voltage power and signal connections, and then we have a whole other group of products that are specifically designed for high-speed data. More recently, with innovations in the market and the switch to zonal architectures, the lines between these different categories have started blurring. We have controllers now that are power-hungry, so they need high-power connections. They bring in information from multiple sensors—it’s simple signals, but they also need to be able to communicate with other controllers and devices like cameras, so there’s high-speed data connections in there as well. We are working on a portfolio of what we call mixed and hybrid connections, which have signal, power, and high-speed data connections, all in a single connector.
Charged: What about wireless data? I’ve heard about wireless battery management systems. Is that a trend?
Pradeep Moorthy: We have seen them in specific instances, but they’re not broadly adopted yet. Even in the battery example, the wireless connections are inside the battery pack, but there are still wired connections from the pack to the rest of the vehicle. If there are routing challenges, packaging space-related concerns, then it might make sense, and we’ll probably start seeing more wireless connections. But purely from a cost standpoint and from a security standpoint, implementing those will be hindered for some time to come.
Helio Wu: I also think the functional safety is another point to consider. Because the battery is such a critical module, we need some kind of redundancy. I think for wireless communication, maybe we need two connections—one wireless and the other using actual wire as a backup.
Charged: As auto manufacturers and suppliers move towards 48-volt architectures, what are the biggest challenges they are going to face?
Pradeep Moorthy: As I said, an overall switch to 48-volt is still a monumental exercise to take on. There are so many things, not just the connectors, but the devices within the vehicle, that have to be modified to accept 48 volts. Simply from a resource standpoint, there needs to be significant investment in making that switch. And there’s the classic chicken-and-egg problem—the OEMs are not willing to switch unless the suppliers are ready to support that switch to 48-volt with their devices, but the suppliers may not be willing to make that investment until the OEMs are ready to bring 48-volt vehicles to market.
A good first step to overcome this challenge is the coexistence of both 12 V and 48 V in the short term. This will enable OEMs to use 48-volt for specific applications which are particularly power-hungry, where they can get a significant benefit from copper reduction, thermal management and the different advantages that we spoke about, without necessarily changing every single device within the vehicle.
Charged: I’m sure you work closely with auto OEMs, and you’re probably advising them on how to make the transition. What’s an important piece of advice that you would give to an automaker to help them more easily transition to 48-volt?
Pradeep Moorthy: I’d say the most important thing is to keep the system-level benefits in mind, and to communicate that effectively to all levels. The switch from 12 V to 48 V does mean redesigning and replacing familiar devices and components. This could lead to higher costs at a component level, but we cannot lose track of the big-picture net savings.
The switch from 12 V to 48 V does mean redesigning and replacing familiar devices and components. This could lead to higher costs at a component level, but we cannot lose track of the big-picture net savings.
Charged: There’s also talk of a transition in the overall vehicle architecture from 400 volts to 800 volts. Does that have any relation to the 12 V/48 V transition, or are these two separate areas?
Pradeep Moorthy: They’re definitely separate areas. The 400 and 800 V architectures are for EV powertrains. Helio and I are in the Signal and Power Connectivity Group, working with low-voltage applications that are non-powertrain-related, but TE Connectivity does offer connectivity solutions for both 400 and 800 V applications.
Charged: Some people find it hard to understand why an EV still has an ordinary lead-acid battery. I try to explain to them that all the accessories are designed to run on 12 volts. Does the shift to 48-volt bring us closer to the day when that lead-acid battery can go away?
Helio Wu: Yes. If in the future 48-volt becomes the single power source in the low-voltage system, then that 12-volt battery will go away. The 48-volt battery would be a new technology, maybe a lithium-ion battery.
Pradeep Moorthy: Right. But it’s important to remember that you’ll still have a second battery for 48-volt. You’re not going to drive all the devices on the vehicle from the main traction battery, because there are still going to be applications in the vehicle that need to be running when the vehicle is turned off, and you do not want to be drawing power from the main battery all the time.
Charged: I know when a new technology is developing, the role of standards is very important. What’s the state of industry standards when it comes to the 48-volt transition?
Helio Wu: Because this is a new transition, standardization is important because it helps everybody to scale up faster. And the earlier we can scale up, reach the higher operational scale, the better we can realize those economy gains for everybody. That’s why TE has developed a standard interface for a 48-volt connection system, and we are actively working with different OEMs as well as device makers, to try to help everybody to connect the dots. That’s what we do, connectivity.
From my perspective, I think the standards have been well established, looking back several years, roughly from 2016 or 2017. At that time, 48-volt was also a hot topic, but in a different context. At that time, people were talking a lot about 48-volt in mild hybrid vehicles because that is a low-cost entry point for vehicle electrification. Still today we can see a lot of 48-volt mild hybrid vehicles in the European market or in Asia. Now the interest in 48-volt is being driven by the low-voltage architecture for powering accessories. However, due to the activity several years ago, we already have a lot of established standards and technical requirements from organizations such as SAE, ISO, etc.
Charged: What are some exciting innovations coming up in the near future?
Pradeep Moorthy: For TE as a company, harness connectors and terminals are our core business, but we also have several other solutions that enable the switch to 48-volt. We are working on data/signal hybrid connectors on both harness and device sides that will package better as our customers switch to zonal architectures. We also have heat-shrink tubing, relays, EMI filtering products, etc, and we are making sure to have all of them 48-volt-ready as well. When an OEM is ready to make that switch, TE can be a one-stop shop.
