Electrical/Electronic Architecture (EEA)

Electrical/Electronic Architecture (EEA) refers to an integrated vehicle-level electrical and electronic solution that unifies various onboard sensors, Electronic Control Units (ECUs), wiring harness topologies, and electrical distribution systems to manage computing, power, and energy distribution. If a vehicle is likened to the human body, the mechanical structure acts as the skeleton and the powertrain serves as the limbs, whilst the electrical/electronic architecture functions as the nervous system and brain—the key enabler for data communication and complex vehicle functions.

Origins of the Concept

The EEA concept was first pioneered by automotive tier-1 supplier Delphi in 2007. Prior to this, automotive electronics were merely piecemeal additions of standalone functions, lacking top-level systematic design. By holistically designing and optimising all electronic-dependent hardware and software—ranging from engine management and power window controls to in-car entertainment systems—Delphi fundamentally resolved the communication bottlenecks and efficiency limitations in automotive electronics.

Core Components

EEA encompasses onboard computing and control hardware, software, sensors, communication networks, and power distribution systems. Governed by specific logic and engineering standards, it seamlessly integrates individual subsystems into a cohesive whole to execute complex functions, comprising:

• Hardware Layer: Physical components such as sensors, ECUs, and actuators

• Software Layer: Embedded software, middleware, and application algorithms

• Communication Layer: In-vehicle network protocols including CAN, LIN, FlexRay buses, and Automotive Ethernet

• Electrical Distribution Layer: Power management, wiring harness topology, fuse, and relay systems

Architecture Evolution: From Distributed to Centralised Computing

The evolution of EEA represents a steady shift towards centralised computing power, serving as the essential foundation for vehicles to transition from "fixed hardware functionality" to "software-defined vehicles". The evolutionary roadmap proposed by Bosch has been widely adopted across the industry and is divided into three primary phases:

Distributed Architecture (Modular → Integrated): Dedicated ECUs are deployed for individual functions, with each ECU operating independently. As vehicle features multiplied, ECU counts escalated from dozens to over a hundred, resulting in intricate wiring harnesses, soaring production costs (for instance, the wiring harness in the Audi Q7 stretched over 6 km and weighed up to 70 kg), and tightly coupled hardware-software stacks that prevented carmakers from delivering independent Over-the-Air (OTA) updates.

Domain-Centralised Architecture (Centralisation → Domain Fusion): Systems are categorised into functional domains (powertrain, chassis, cockpit, ADAS/smart driving, etc.), where high-performance domain controllers consolidate multiple ECU functions. By upgrading from a distributed layout to a domain-based architecture, XPeng consolidated over 30 standalone ECUs into just 4 domain controllers. The Tesla Model S stands as a classic early benchmark.

Centralised Architecture (In-Vehicle Central Computing → Vehicle-Cloud Computing): Built around a high-performance central compute platform paired with 2 to 4 physically located Zonal Control Units (ZCUs) forming the vehicle's core backbone. With this architecture, the Tesla Model 3 reduced its wiring harness length to 1,500 metres, while the Cybertruck further slashed it down to 500 metres. This layout genuinely decouples software from hardware, allowing the vehicle to continuously evolve via OTA updates.

Future Outlook: EEA is rapidly transitioning from "functional domains" to "physical zones", advancing towards the ultimate setup of "central computing + zonal control". High-speed Automotive Ethernet is replacing conventional CAN/LIN buses as the primary backbone network, whilst Service-Oriented Architecture (SOA) enables software features to be flexibly configured and continuously iterated. EEA is not merely a technological upgrade, but the vital architectural foundation empowering carmakers to transition from traditional hardware manufacturers into software-driven service providers.