Power & Data Matter: 4 Design Considerations for Electric Vehicle & Autonomous Driving Applications

Professional Engineer Works on a Computer with a 3D CAD Software and Tests the Electric Car Chassis Prototype with Wheels, Batteries and Engine Standing in a High Tech Development Laboratory.The evolution of electric vehicles and autonomous driving capabilities has led the auto industry to rapidly pursue technological changes that represent a paradigm shift in how vehicles are made.

Results of a recent Molex survey conducted by third-party research firm, Dimensional Research, of 230 automotive manufacturing decision-makers revealed 91% of the respondents believed that by 2030 all newly purchased cars will be either fully electric or hybrid. Further, 94% stated they expect new cars will all have some degree of autonomous functionality within the same timeframe.

This means that within a decade or so, nearly all cars and trucks will be technologically unrecognizable when compared to their predecessors, and two of the most significant challenges from a design standpoint are in the areas of DC power and high-speed data. So, what are the key considerations the electric and autonomous designers must take into account to ensure proper functionality, performance and competitive capability given their complexity?

Design Consideration #1: High-Voltage Powertrains

Two Automotive Engineers Working on Electric Car Chassis Platform, Taking Measures, working with 3D CAD Software, Analysing Efficiency. Vehicle Frame with Wheels, Engine and Battery.

As electric vehicles in their various forms replace mechanical and hydraulic systems, there is greater demand for DC power, which can’t be delivered by the typical 12V DC systems. Even internal combustion engine and “mild hybrid” vehicles are seeing an evolution of basic electrical systems with increases commonly quadrupling voltages to 48V DC, and power requirements for all-electric vehicles start at 400V DC.  In turn, higher voltage delivers greater efficiencies, realized by the need for smaller-diameter wire, decreasing cost and weight, and reduced charging times.

To ensure proper safety in the high-voltage environment of an electric powertrain, interconnects require greater degrees of isolation. Additionally, the harsh operating environment of a vehicle powertrain requires strong connections that can withstand various heat, moisture and vibration conditions. Operational reliability is also critical in preventing vehicle failures and the associated repair costs.

Design Consideration #2: Keeping Power Under Control

The battery management system (BMS) plays a key role in ensuring the safety and reliability of electric vehicle batteries, as it monitors the health and charging state of the battery cells. The BMS relies on sensors distributed throughout the battery that monitor current output, temperature and other factors. As a result, interconnects play a vital role in ensuring that nothing occurs to disrupt this relationship.

Power Connectivity Solutions

Tier 1 suppliers face the challenging opportunity of providing a growing number of BMSs and powertrain motor control modules to automakers, who are racing to meet the market demands for hybrids and EVs. In response, Molex leveraged its automotive industry expertise along with consumer device experience to develop micro-interconnect solutions with design features needed for the latest EV technology while also being robust enough to perform reliably under harsh conditions.

For example, Molex has designed FPC-to-board connectors for use in BMS applications that have a low-profile and contacts that are slightly recessed so they cannot be damaged if the mating shell is ‘scooped’ into it during mating. Additionally, the dual-beam contact delivers integrity of the connection even under high levels of vibration and thermal shock. As a result, customers can have confidence these high-caliber micro-interconnect products provide dependable and robust power for battery management.

For high-voltage powertrains, Molex has designed compact 1.00mm-pitch high-power board-to-board connectors with a dielectric withstand value of <100mA (when voltages under 500V are applied), plus >100 Megohms insulation resistance (below 1,000V AC/1,600V DC). Additionally, these connectors have a deep wipe length of ±1.75mm and dust-proof terminal covers to help mitigate the risk of short circuits, delivering the reliability and safety both automotive and consumer device customers have come to expect from Molex.

Design Consideration #3: Meeting Data Requirements

Automotive sensing system concept. Autonomous car. Driver assistant system. Adaptive cruise control.Turning the focus to high-speed data, cars have relied on controller area network (CAN) and local interconnect network (LIN) technology for decades. However, the data rate limitations of these protocols make them incapable of handling the amount of data produced by electronic control units (ECUs), cameras, radar, lidar and the other data-producing devices within today’s vehicle. Therefore, the widespread adoption of Ethernet-based connectivity and zonal architectures will enable more efficient data transmission throughout the vehicle, reducing cabling weight and cost. In zonal architecture, ECUs will be replaced by domain controller units (DCUs), which are expected to proliferate.

 Design Consideration #4: High-Performing Cameras

As vehicles move toward higher levels of autonomy, the number of ADAS cameras inside and outside the vehicle is increasing, with some car models already having 10 to 12. These cameras also will require high-speed data transfer and low latency to quickly inform driver safety systems of potential hazards. Additionally, cameras must provide 8-megapixel resolution, compared to the 1.3-megapixel-resolution cameras generally deployed today.

As camera modules get smaller, they require single PCB arrangements, which creates additional electromagnetic interference (EMI) due to more densely packed components. Finally, both the camera and cabling must operate reliably under harsh conditions, including high degrees of shock, vibrational forces and extreme temperatures.

High-Speed Data Solutions

To accommodate these high data rate requirements, Molex camera cable assemblies have bandwidths from 3 to 6 GHz, and they include features that deliver a robust connection, such as retention force capabilities to withstand 110 N. Integrated plastic backshells (rather than heavier aluminum ones) also prevent EMI from impacting signal integrity performance. At the board level, Molex connectors for PCIe Gen 4 have up to 200 contacts and support data rates up to 20 Gbps, more than enough bandwidth to accommodate in-vehicle networking requirements.

Recognizing and resolving these four key considerations early in the design phase will help optimize performance and capabilities to drive EV and ADAS/AD applications to achieve their highly anticipated potential.

You can learn more about Molex automotive micro-interconnect solutions in our tech briefs: “Micro-Interconnect Solutions Addressing Electric Vehicle Demands” and “Micro-Interconnect Solutions for Increasing Vehicle Autonomy”.

Director of Advanced Micro Products