Key Applications of Flexible PCBs in Automotive Electronics

In today's rapidly evolving automotive industry, electronics have become the backbone of vehicle innovation. From advanced driver-assistance systems (ADAS) to electric vehicle (EV) power management in modern cars. Flexible printed circuit boards (flex PCBs) stand out as critical components in design freedom.

Automotive electronics now account for about 40% of a vehicle’s total manufacturing cost, a figure that is expected to rise to 50% by 2030. In this article, we explore the pivotal role flexible PCBs play in modern automotive electronics.

1.    What Are Flexible PCBs?

Flexible PCBs are circuit boards made from flexible base materials like polyimide or polyester films. Similar to rigid PCBs, FPCs can bend, twist, and fold to fit into smaller shapes. They can be single-sided, double-sided, or multilayered all discussed below.  They can be combined with rigid sections to create rigid-flex circuits for even greater versatility.

2.    Types of PCBs Used in Automotive Applications

Automotive applications need high-performance PCBs that can tolerate conditions like extreme temperatures and vibrations. The primary types of PCBs used in automotive systems include:

3.    Innovations in Automotive PCB Technology:

FPC promotes the development of cutting-edge automotive technologies. These days we have tech like organic light-emitting diode (OLED) displays, flexible touch screens and flexible sensors inside the car. PCBs are now being designed to integrate artificial intelligence (AI) and the Internet of Things (IoT), enabling smarter and more connected vehicles. Not only that nowadays we have advanced camera systems, ADAS, control over wheel pumping, head-on-display and much more. These advancements enhance functionalities such as predictive maintenance and real-time monitoring.

Types of Flex-Rigid PCBs:

⦁ Semi-flexible PCBs: They are made from thin FR-4 material, suitable for applications with low flexibility requirements and lower manufacturing costs.

⦁ Multi-flexible PCBs: It uses polyimide material, suitable for applications with high dynamic flexibility requirements.

Multi-flexible PCBs consist of a hybrid structure where rigid and flexible substrates are connected using electroplated vias. The flexible part consists of a copper foil on a polyimide substrate which ensures high mechanical stress resistance.

4.    Advantages of Flex-Rigid PCBs in the Automotive Industry

Increased Quality and Reliability: By reducing the number of connectors and solder joints, the risk of electrical failure is minimized. This increases the overall reliability of automotive control systems.

Simplified Maintenance: Flex-rigid PCBs combine rigid and flexible parts, allowing for compact and precise integration into small spaces.

Greater Flexibility in Design and Assembly: With this designers can focus on the layout of the rigid parts of the PCB, and the flexible parts can serve only for interconnection.

5.    Why Automotive Systems Demand Flexibility

Modern vehicles are becoming increasingly compact and feature-rich. Designers must integrate more electronic functions into smaller spaces without extra weight. Here’s why flexible PCBs are uniquely suited for automotive applications:

1. Space and Weight Reduction:

Space is always premium in modern automotive designs, particularly with the rise of EVs. Usually if there is any space left we want to utilize it for more power or battery backup. With the usage of FPC circuits can be folded or contoured along the vehicle’s structure. This leads to significant weight savings in terms of wiring, which improves fuel efficiency and extends EV range.

2. Reliability Under Harsh Conditions:

Automotive faces extreme temperatures, vibration, mechanical stress and moisture. In FPC materials like polyimide provide high thermal resistance (up to 250°C) and chemical durability. Which ensures long-term reliability even under severe operating conditions.

3. Design Freedom and Complexity Management:

Flexible PCBs provide three-dimensional routing capabilities. Complex assemblies like camera modules, infotainment systems, and battery management systems can be put more efficiently using flex circuits. By reducing the number of interconnects the rate of failure of devices also decreases.

6    Key Applications of Flexible PCBs in Automotive Electronics

The versatility of flexible PCBs is leveraged across multiple automotive subsystems:

1. Advanced Driver-Assistance Systems (ADAS)

ADAS technologies rely heavily on PCBs to process and transmit data from cameras, radar, and lidar sensors. They provide functions such as lane-keeping assistance and adaptive cruise control.

2. Electric Vehicle (EV) Battery Management Systems (BMS)

The shift towards electric mobility has created a significant demand for PCBs. They are essential in EVs for managing high-voltage power distribution and battery management. The ability to handle high current loads and operate in thermal cycling conditions makes FPC ideal for BMS applications.

3. Lighting Systems

FPC is used in LED lighting systems, including adaptive headlights, tail-lights, and interior ambient lighting.  Their ability to fit into slim and custom-shaped housings. Which enables innovative lighting designs that improve both aesthetics and safety.

4. Engine and Transmission Control Units

PCBs are integral to the operation of engine control units, transmission control units, and other powertrain systems. They ensure precise control and monitoring of engine performance.

7.    Challenges and Considerations

Despite their advantages, the use of flexible PCBs in automotive electronics comes with certain challenges:

⦁ Cost: Flex circuits can be more expensive to design and manufacture than traditional rigid boards. The cost depends upon production volumes.

⦁ Manufacturing Complexity: Handling and assembly of flexible substrates require specialized processes to prevent damage.

⦁ Material Selection: Choosing the right adhesive systems, coverlays, and surface finishes is crucial to ensuring performance under automotive stresses.PCBs in automotive applications are exposed to extreme conditions, necessitating the use of specialized materials and designs to withstand stress.

⦁ Testing and Validation: Automotive PCBs must comply with strict standards to ensure safety and reliability. This requires advanced testing and certification processes, which can increase production costs. Usually to meet automotive quality standards like AEC-Q200 and ISO 26262 compliance are the main criteria.

Conclusion

Flexible PCBs are no longer a niche technology in automotive electronics; they are a core enabler of modern vehicle functionality. As automotive technology continues to advance, the demand for flexible PCBs will only grow. Emerging trends such as:

⦁ Autonomous vehicles

⦁ Vehicle-to-everything (V2X) communication

⦁ Augmented reality (AR) head-up displays

⦁ Smart interiors with haptic feedback surfaces

This article provides valuable insights into the critical role automotive flexible PCBs play in driving automotive innovation. With applications and future prospects in the automotive industry. Flexible PCBs will be an integral part of shaping the future of automotive innovation.

As the automotive industry advances, leveraging high-quality PCB suppliers such as JLCPCB can provide the competitive edge needed for successful innovation, thanks to their expertise in flexible and rigid-flex PCB manufacturing