1. Definition and Classification of Automotive Electronics
Automotive PCBs refer to printed circuit boards made for use in vehicle electronics. Car electronics fall into two main groups. One group is body electronics control systems. The other group is in-vehicle electronics control systems. Body control systems can be broken down further. They include engine control systems, body control systems for doors and lights, and chassis control systems. Body control systems connect car mechanical parts with electronic parts. They let electronics make mechanical parts work better. They help the car run smoother and safer.
In-vehicle electronics systems include the car multimedia system, navigation system, driving recorder, reverse parking radar, and other systems. These systems make the car easier to use and add entertainment features. They change how drivers and passengers use the vehicle. They improve the overall user experience.
2. Growing Demand Driven by Automotive Intelligence
As cars get smarter, use of automotive PCBs goes up. Signals run faster and at higher frequency. So PCBs must be efficient and very reliable at the same time.
3. Core Advantages of Automotive PCBs
PCBs are used more and more because they have many strong benefits. They allow high density of parts. So they evolve with the higher integration of integrated circuits and with better mounting technology. They are also very reliable. Many inspection, testing, and aging tests help make them work for a long time without failure. The most important point is that PCBs can be assembled. PCBs make it easy to mount standard parts. They fit automated and mass production. You can assemble PCBs with other parts to make larger modules, systems, and whole machines.
4. Higher PCB Demand in New Energy Vehicles
Compared with traditional cars, new energy vehicles use more electronic panels. On one hand, the electronic systems in new energy cars need more electronic control than in traditional internal combustion drive systems. On the other hand, the core of new energy vehicles is the battery, motor, and electronic control. These parts raise the electronic content much higher than in conventional cars. These two factors increase how many PCBs a car needs. They also push PCB types from low-cost boards to higher value boards. The per-vehicle value of automotive PCBs keeps rising.
Process Requirements for Automotive PCBs
1. Material Selection
For any PCB, the material quality strongly affects the whole product quality. When making an automotive PCB, you must think about how car environments affect materials. So choose high quality materials for automotive PCBs. Pick materials that can handle high and low temperature, high pressure, and other harsh conditions.
High-Tg substrates: Use epoxy resins with Tg ≥ 170°C. (Normal FR-4 has Tg around 130°C.) At 150°C, the flexural strength drops to only about one sixth of what it is on ordinary substrates.
Polyimide (PI): Use PI substrates with Tg up to 260°C near turbochargers. PI can handle short-term extreme environments up to 200°C.
Choose materials for strength and long-term stability. Choose materials that resist heat, moisture, and chemical stress. These choices help the PCB keep stable electrical and mechanical properties in the car.
2. Design Rules
Making automotive PCBs is a complex process. To make a proper automotive PCB, follow many design rules and manufacturing standards. PCB designers must know these rules. Designers must follow standards closely.
Table of common process challenges, solutions, and results:
| Common Challenges | Solutions | Results |
|---|---|---|
| Vibration failure | Thick-wall plated through holes (copper layer ≥ 25 μm) and rounded corners. | No detachment after one million vibration cycles (ten times the consumer level). |
| Heat bottleneck | Embedded copper blocks and micro-hole arrays (hole diameter ≤ 0.2 mm). | Local thermal resistance drops by 35%. IGBT junction temperature < 125°C. |
| Soldering risk | Use SAC305 lead-free solder (melting point 217°C) and gold-plated pads. | Solder joint strength retains over 95% at 150°C. |
Design work should also cover layout, spacing, pad sizes, vias, and thermal relief. Use rounded trace corners and proper via placement. Pay attention to mechanical mounting holes and board edges. Add reinforcement where the board mounts to the chassis. Make sure the board meets the vehicle’s vibration and shock requirements.
3. Process Flow
During automotive PCB manufacturing, follow a set of standardized process steps. This ensures a smooth production cycle. Watch the details at each step. Add quality checkpoints at key steps to make sure the final product meets requirements. Do visual inspection, dimensional checks, electrical testing, and environmental testing at defined points. Use automated optical inspection (AOI), x-ray, and flying probe tests to find defects early.
4. Technical Development Directions
Beyond the process needs above, watch emerging PCB technology trends. Electric vehicles, advanced driver assistance, and self-driving cars push PCB technologies forward. Main future directions include:
Multilayer board design: As signal quality demands grow, multilayer designs become more common. More layers help with signal routing and grounding and help control impedance.
High-speed signal transmission: Cars need faster information exchange. High-speed signal design is a core technology. Control impedance, use controlled dielectric, and place ground planes properly.
Miniaturization and lightweight design: Car bodies push for smaller, lighter parts. PCBs must meet new cost and stability needs. Thinner boards and compact designs help save space and weight.
Overall, automotive PCBs require high technical and process standards. You must consider many aspects to meet these needs. Only then can you guarantee PCB performance and quality. As technology advances, the automotive industry will keep getting smarter. The PCB industry will also keep innovating and improving.
Power and Ground Routing for Automotive Electronic PCBs
In car audio and video systems like CD and VCD players, many CMOS digital devices and mixed-signal analog devices are used. When these devices work at the same time, they cause power and ground level changes on the PCB. These changes lead to signal spikes, overshoot, or damped oscillation.
A proper power routing layout aims to reduce voltage drop and high-frequency electromagnetic conversion noise caused by lines and impedance. Do not design power traces with thin middles and thick ends. That pattern can cause big voltage drops. Use large radius bends instead of sharp turns. A rounded arc shape is better. Make vias larger where allowed. Add filter capacitors near vias when possible.
Ground routing helps electromagnetic compatibility (EMC) in two main ways. First, ground reduces signal loop area. That reduces radiation and improves immunity to interference. Second, ground reduces crosstalk between traces or circuits. Ground gives electromagnetic energy a good return path back to the source. This keeps energy from reaching protected conductors.
The characteristic impedance of PCB traces directly affects board immunity to interference. Lower resistance reduces common impedance and then reduces ground line interference.
Divide the board into functional zones. Link the ground lines of each zone in parallel and then tie them to a single point. If the board has multiple circuit units, give each unit its independent ground return loop. Then connect each unit to a single common ground point. This keeps the ground current of one unit from flowing into others. It avoids mutual crosstalk.
Make power and ground traces as wide as possible. For devices with 0.5 mm pitch, keep trace width no less than 0.3 mm (12 mil). On mixed-signal boards, separate digital ground from analog ground. If not, electromagnetic radiation and signal crosstalk can increase sharply. That causes EMC problems. So place digital and analog circuits in different zones for layout and routing.
Signal Routing in Automotive PCBs
In cars, wire bundles are common. Different voltage levels, current sizes, and directions are bundled together. Poor placement of sensitive components, or low quality components, can create electromagnetic interference (EMI). Bad signal routing can cause noise. When you layout signals, pay attention to these rules:
Avoid sudden impedance changes on signal traces.
Reduce signal loop sizes to cut radiation.
Make sure traces on adjacent signal layers are orthogonal to each other.
Place high-speed digital and low-level analog signal traces next to ground planes. Put low-speed and high-level analog traces on layers farther away.
Avoid parallel routing of input and output lines. That reduces feedback coupling.
Use differential pair routing for high-speed signals. That lowers electromagnetic radiation.
Application of FPC in New Energy Vehicles
1. Limitations of Traditional Copper Wire Harnesses
Collector lines are essential parts of the BMS (battery management system) in new energy vehicles. They monitor cell voltage and temperature of power battery cells. They connect data collection and transmission and often have overcurrent protection. They protect battery cells and disconnect automatically on short circuits.
Before, battery collector wiring used traditional copper wire harnesses. Each harness used copper insulated by plastic. When many current signals exist, many harnesses were needed. That takes up space. In the pack assembly step, workers fixed harness ends manually to the battery pack. That gives low automation.
2. Advantages and Details of FPCs
Compared with copper harnesses, FPCs (flexible printed circuit boards) have advantages. They are highly integrated, very thin, and highly flexible. These traits help in safety, light weight, and neat layout. Also, FPCs are thin and can be custom fit to the battery pack. During assembly, robot arms can pick and place them directly on the battery pack. That makes automation easier and supports mass production. FPCs clearly tend to replace copper harnesses.
Advantages and details:
Safety performance: FPCs use metal foil to connect to busbars. They can include fuse protection design. This ensures high-speed signal paths. If a short happens, the FPC fuse melts and cuts the line. This prevents fire or explosion in other parts of the battery pack.
Lightweight: Compared to wire harnesses and some PCBs used for signal collection, FPCs take less space and weigh less.
Process flexibility: FPCs remove many manual connector steps. They allow ultrasonic welding, soldering, and other processes. In thickness, the circuit area can be 0.34 mm and the NTC area 2 mm. They can bend 90° or 180°. These features give strong design freedom.
Automated production: FPCs have regular shapes and high integration. They reduce manual wire routing. They suit mechanical, large-scale production. This greatly cuts assembly time and labor. They support automation for battery pack assembly.
Automotive PCB Market
1. Market Drivers and Key Certifications
In recent years, the rise of new energy vehicles has driven PCB industry growth. PCBs are the structural base for electronic parts. They play key roles in power control, safety control, body electronics, and infotainment systems.
New energy vehicles need more electronic control than traditional fuel cars. Trends like electrification, intelligence, and network connection increase demand for high-end automotive PCBs. This demand has strict reliability requirements. Often the PCBs must pass long tests. Tests can last one to three years before a part gains supplier approval.
The automotive electronics industry has strict standards for car-grade products. Key certifications include AEC-Q100, IPC-6011, and IATF 16949. These standards raise the barrier to entry and create a technical moat for qualified PCB suppliers.
Global automotive PCB market continues to grow. New energy vehicle adoption is a key driver. As a global leader in electric vehicles, Tesla uses a large amount of PCBs per car. In Tesla Model series, inverter parts and BMS use many PCBs. That increases the PCB value per car.
Electrification and intelligence trends will keep pushing the market. The Asia-Pacific region and China will continue to see strong growth. Domestic manufacturers in China still have room to grow in the global market.
2. Types of Automotive PCBs
Automotive PCBs include multilayer PCBs, flexible PCBs (FPC), HDI boards (high-density interconnect), high-frequency PCBs, and other types. Each type has different materials and uses. Each fills a role in different scenarios.
3. Market Data and Trends
Market numbers and trends (summary from industry data):
A forecast showed the global automotive PCB market was $8.84 billion USD in 2022. It is expected to reach $13.39 billion USD by 2030. The compound annual growth rate (CAGR) is 5.6%.
In the Asia-Pacific region, the market was $4.42 billion USD in 2021. It rose to $4.83 billion USD in 2022.
New energy vehicle growth is the main factor driving PCB demand. In 2019, single-vehicle PCB values were roughly: low-end cars $30–40, mid-range cars $50–70, high-end cars $100–150. With electrification and other trends, per-vehicle PCB value should rise sharply. A forecast predicted the global automotive PCB market would reach $12.48 billion USD by 2028. The CAGR from 2020 to 2028 was about 5.3%.
Another forecast estimated the global new energy vehicle PCB market size would reach RMB 30.095 billion by 2025. Its CAGR is much higher than for traditional fuel vehicles. By contrast, the traditional fuel vehicle PCB market was expected to fall to about RMB 32.925 billion by 2025.
Automotive PCB demand is concentrated in multilayer boards and HDI high-end areas. Market competition is larger in the mid and low end.
Data from Jycircuitboard on PCB type share in the automotive market shows:
1–2 layer PCBs: 26.93%
4-layer PCBs: 25.70%
6-layer PCBs: 17.37%
8–16 layer PCBs: 3.49%
HDI boards: 9.56%
FPCs (flexible PCBs): 14.57%
IC substrates: 2.38%
These numbers show multilayer boards are the main need in vehicle electronics. HDI and FPC have important roles in high-end applications.
Closing Summary
Automotive PCBs face strict technical needs. You must choose the right materials. You must follow tight design rules. You must use controlled manufacturing steps and strict testing. You must focus on power and ground routing and on proper signal routing. FPCs are becoming more common in battery systems. The market grows with vehicle electrification and intelligence. High-reliability, multilayer, HDI, and FPC boards will be in strong demand. Manufacturers need to meet standards and test cycles. Doing so will let suppliers take part in the growing automotive market.