Zonal Electrical Architectures Cut Vehicle Wiring-System Cost, Complexity - Tech Briefs

Multiple trends are driving the evolution of electric vehicles (EVs), hybrid-electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). Urbanization and sustainability pressures have spurred governments worldwide to issue supportive regulations, benefiting manufacturers, while tax incentives have motivated consumers to adopt electrified models. All-electric vehicles will reach 13 percent of all light-vehicle sales in 2023 and five countries are leading the way. In Norway, EV sales represented 80 percent of all passenger vehicles in 2022; in Iceland, it was 41 percent; Sweden, 32 percent; the Netherlands 24 percent, and China 22 percent.

The quick pace of innovation for high-voltage propulsion systems and vehicle electrical architectures now is driving a radical rethinking and redesign of low-voltage electrical and electronics (E/E) architectures and these platforms’ associated wiring and connector components. Many global vehicle programs already have shifted from the legacy distributed E/E architectures to domain-centralized E/E architectures – and will require another change to zonal E/E architectures to accommodate the inclusion of complex, high-voltage systems powering ADAS and automated-driving functionality.

Although just 2 percent of vehicles currently have zonal E/E architectures, by 2034 the proportion is predicted to be 38 percent. Auto manufacturers such as BYD, Nio, Stellantis, and Tesla already offer vehicles with zonal architectures, pushing others to move faster in adopting them.

Today, manufacturers of electrified vehicles use software not only to improve safety, comfort, and infotainment features, but also to enable increased electrification, ADAS/AV features, shared-mobility services, and interconnected transportation systems. In the future, vehicle functionalities and the related software will be developed independently from the hardware on which it operates and will be updated throughout its entire vehicle lifetime – leading to the “software-defined vehicle” (SDV).

To make this happen, the automotive industry is learning software architectures and development methods well-known in the telecommunications and computer industries and adopting them in a more sophisticated way. The challenge is to transfer the advantages of the tech industry to more intensive requirements of the automotive industry, and at the same time to orchestrate the necessary design changes and hardware developments in a complex supply-chain environment.

Here’s how the electrical distribution system, including its wiring and connections, is impacting changes to vehicle E/E architectures:

Moving away from “distributed architectures.” With distributed architectures, auto manufacturers could drop in new functionality by adding new electronic control units (ECUs) – space permitting. Luxury models with distributed architectures use more than 100 ECUs and have up to 4 km (2.5 miles) of wiring harnesses under the hood.

However, distributed architecture no longer is the right fit for the future, due to cost and safety considerations. On one hand, new software-based functions, for example, using sensor information from different domains, drive higher integration costs. On the other hand, more “connected” ECUs offer more chances for cyberattacks due to multiple potential digital access points from the outside. A revision of the E/E architecture – and thus of the electrical distribution system – has become necessary.

Adopting domain architectures: Domain architectures enable systems to be logically organized and are suitable for cloud connectivity. For example, ADAS, infotainment, telematics. and gateway systems all are grouped, each with its own processor. Although a major advancement over distributed architectures, domain architectures increase the amount of wiring and connections, therefore increasing vehicle weight and cost. As a result, these domain architectures ultimately are not the most efficient way to organize vehicle electrical systems.

Shifting to zonal architectures: With zonal architectures, systems are logically and physically grouped into zones that can be efficiently organized. In each zone, all systems are managed by the same processor, have their own power distribution unit, and are connected to the Ethernet via a gateway, then to the central vehicle computer. A few ECUs can manage the entire vehicle while at the same time enable advanced functionality. Luxury models will have more zones to deliver more-advanced capabilities, while basic vehicle will have fewer zones and systems. In addition, low-voltage data connectivity and high-voltage drive systems are segregated but work in parallel.

In zonal arrangements, because the ECU is closer to actuators and sensors, less wiring and fewer connections are required. Manufacturers benefit by enabling efficient connectivity, reducing weight and cost, and enhancing overall reliability.

Zonal architectures support powerful functionality and capabilities:

Enabling complex applications: Zonal architectures promote control via well-structured, clean, and safe software code that at the same time can bring new, complex software functionalities, e.g., higher levels of driving automation, which can help auto manufacturers more quickly develop and deploy high-level driving automation.

Over-the-air (OTA) updates: OEMs can easily update software by simply “flashing” new features or updates to improve software stability and security.

Subscription services: Software-defined vehicles unlock the ability to deliver onboard subscription services. Consumers might opt for basic, mid-level, or luxury packages when buying a new vehicle. However, OTA means they also can add or cancel other services whenever desired. For example, consumers might opt for heated seats in the winter or add a luxury infotainment package for a road trip.

Zonal architectures offer auto manufacturers and consumers multiple benefits:

Reduced cost: Wiring lengths are drastically shortened through optimized device placement and some cables are eliminated through functional integration. Alternatives to the round stranded conductors such as flat flexible cable (FFC) and flexible printed circuit (FPC) increasingly enter the market and enable increased automation in production and handling. As the industry continues to standardize, new solutions that offer greater functionality at lighter weights will continue to deliver operational efficiencies and cost savings.

Accelerated innovation: With zonal architectures, hardware and software are separated. That enables OEMs to innovate in parallel, as well as push new features and services via OTA.

Functional integration: There are fewer devices with more integration due to centralization and zonal architectures. Integrating multiple functional systems into one device decreases the packaging space and reduces complexity of the connections.

More assembly automation: Automation becomes a driver to lower cost and increased quality. Lighter wiring harnesses are easier to install with robots, which also don’t fatigue, driving throughput. In addition, OEMs can standardize sub-harnesses, simplify operations, and reduce development costs.

Greater flexibility: The market will move to standardized, modularized solutions, enabling auto manufacturers to save space for other systems. Sub-harnesses will be installed in these modules and then integrated into vehicle architectures. For OEMs, that means gaining greater freedom in where and how assembly occurs.

Improve driving range: Lighter-weight vehicles also benefit consumers, providing greater fuel efficiency for combustion-engine cars and extended driving ranges for electrified models.

Electrification represents a seismic shift in how vehicles are designed, integrated, and delivered. Changes required to liberate the promise of zonal architectures include:

New partnerships: For high-voltage applications, battery, motor, power electronics and materials, providers will collaborate to design new systems. On the low-voltage side, semiconductor manufacturers, materials, and component providers will work together to reduce costs and improve reliability.

Software-driven development: Historically, auto manufacturers and their Tier 1 suppliers have designed hardware, focusing on what software is required to enable new systems. With zonal architectures, the reverse is true. OEMs will design and evolve software to control zones and then consider how hardware needs to change to support it – the hardware must follow the software. This enables a transfer of software development sovereignty from Tier 1 to the OEM. The strict separation of hardware from software through a middleware layer enables independent software/hardware development processes and lifecycles.

Standardization and modularization: OEMs, which will control most software development, will help lead the drive to standardize and streamline hardware distribution. They’ll also modularize systems such as electronics. This will provide greater value to auto manufacturers, enabling them to use systems across more model ranges. OEMs will benefit by increasing operational efficiency and reducing costs.

Higher-voltage power systems: 12V power systems have for decades been the norm. With zonal architectures, 48V will be needed to support systems’ higher power consumption and redundancy requirements. The 48V power net delivers lower power loss and enables lighter wiring harnesses.

Increasingly, OEMs are on notice that they need to innovate more quickly. More auto manufacturers have announced their commitment to SDVs, which require zonal architectures. The speed of development of new E/E architectures will be accelerated to be compatible with the already achieved state-of-the-art in the telecommunications and digital industries. Consumers no longer accept lower standards.

Consumer and business’ growing appetite for electrified vehicles means there is something for everyone. Auto manufacturers and OEMs can collaborate to develop and equip new zonal architectures that enable the advanced functionality and services that buyers covet, unlocking more revenue and subscription-income streams.

Ultimately, zonal architectures require a fundamentally reorganized software structure that allows the OEM to independently, quickly, easily, and modularly adapt the control of the entire vehicle while minimizing the complexity in the wiring harness and the number of control devices. In the meanwhile, more and higher-performance functions and services can be offered to the end user. TE supports this progress with highly efficient and automated high-speed data connections, combined power and data connections, advanced sensors, and a variety of progressive e-mobility solutions.

This article was written by Qiong Sun, Global Vice President, Automotive E-mobility Business, TE Connectivity (Berwyn, PA). For more information, visit here .

This article first appeared in the December, 2023 issue of Battery & Electrification Technology Magazine.

Read more articles from this issuehere.

Read more articles from the archives here.

SUBSCRIBE