Technical Analysis of High-Reliability New Energy PCBA with SiC Devices for 800V High-Voltage Platforms

　　With the rapid evolution of new energy vehicles towards high-voltage and high-efficiency architectures, the 800V high-voltage platform has become a core trend to enhance charging efficiency and extend cruising range. Silicon Carbide (SiC) devices, boasting superior properties such as 3x wider bandgap, 3-5x higher thermal conductivity, and 8-10x higher breakdown electric field compared to traditional silicon materials, have emerged as the pivotal components in 800V powertrain systems, including main inverters, On-Board Chargers (OBC), and DC/DC converters. These devices enable the inverter efficiency to be improved by 10% to 15%, directly extending the vehicle's cruising range and supporting the 800V platform to achieve "5-minute charging for 200km" fast charging performance. The PCBA (Printed Circuit Board Assembly) integrating SiC devices serves as the critical carrier for the stable operation of 800V high-voltage systems, and its reliability directly determines the energy conversion efficiency, thermal management performance, and overall safety of the vehicle. Compared with traditional Si-based PCBA, 800V SiC PCBA faces more stringent challenges in high-voltage insulation, electromagnetic compatibility (EMC), and thermal cycling resistance, especially due to the ultra-high switching frequency and high power density of SiC devices. Leveraging its profound accumulation in precision manufacturing and automotive electronics, Szchaopin has developed a full-process high-reliability PCBA solution tailored for 800V SiC applications, providing robust technical support for the large-scale adoption of 800V high-voltage platforms.

　　Core Reliability Requirements of 800V High-Voltage Platform SiC Device PCBA. The integration of 800V high-voltage systems and SiC devices imposes unique and rigorous reliability demands on PCBA, primarily stemming from four key aspects: First, enhanced high-voltage safety margins. The 800V platform typically operates with a maximum voltage exceeding 900V, requiring PCBA to have excellent insulation performance. The creepage distance and electrical clearance must strictly comply with automotive safety standards, especially to withstand transient voltage spikes caused by SiC's high-speed switching characteristics (a critical issue as SiC MOSFETs generate larger voltage spikes due to higher di/dt during turn-off). For commercial vehicles evolving towards 1000V+ platforms, the PCBA must even accommodate 1700V-class SiC devices, further elevating insulation requirements. Second, superior thermal management capability. While SiC devices exhibit lower losses than Si-based IGBTs, their high power density still leads to significant localized heat generation. The key thermal bottleneck often lies in the bonding layer and thermal interface materials (TIM) rather than the SiC chip itself. Thus, PCBA must effectively dissipate heat to maintain SiC device junction temperature within a safe range (-40℃~+175℃), avoiding performance degradation or failure due to overheating. Third, robust EMC and signal integrity. SiC's ultra-high switching frequency (up to MHz level) generates intense electromagnetic interference (EMI), which can disrupt the normal operation of sensitive components such as BMS sensors. PCBA must achieve efficient EMI shielding and impedance matching to ensure stable transmission of control signals and high-precision sampling of millivolt-level signals. Fourth, enhanced mechanical and thermal cycling reliability. 800V systems are often subjected to harsher operating conditions, requiring PCBA to withstand wide-frequency vibrations (10~2000Hz) and repeated thermal cycles, ensuring no solder joint fatigue or component detachment.

　　Core Technical Implementation Path of Szchaopin's 800V SiC Device PCBA. Aiming at the unique requirements of 800V SiC applications, Szchaopin has constructed a full-chain reliability guarantee system covering design, material selection, process, and testing, fully unlocking the performance advantages of SiC devices:

　　1. SiC-Optimized Refined Design. In the PCB design stage, Szchaopin adheres to the "minimum power loop" principle to match SiC's high-speed switching characteristics, which is crucial for minimizing parasitic inductance. By leveraging High-Density Interconnect (HDI) technology and optimizing the topology of power loops—such as arranging switching tubes, inductors, and input capacitors in a compact triangular layout and adopting star grounding for input capacitor and switch tube grounding—the stray inductance is reduced to ≤10nH, minimizing voltage spikes during switching and reducing dynamic losses. For high-voltage interfaces and SiC device peripheral circuits, a three-dimensional insulation design is implemented, with the creepage distance increased to >15mm to meet the safety requirements of 800V+ systems. Additionally, DFMEA (Design Failure Mode and Effects Analysis) is integrated to conduct risk assessments for potential issues such as thermal runaway and EMI interference, and redundant designs are adopted for key circuits to avoid single-point failures. For embedded SiC module applications, the PCB structure is optimized to realize direct chip embedding, and the SW node copper area is strictly controlled to balance conduction loss and EMI radiation, with sensitive signal lines kept at least 3mm away from the SW node to enhance signal integrity. Furthermore, array thermal vias (0.3mm aperture) are arranged under the chip heat pad to create low-resistance heat dissipation channels, effectively improving heat transfer efficiency.

　　2. High-Performance Automotive-Grade Material Selection. Core materials are strictly selected to match the high-voltage and high-temperature characteristics of SiC devices. The PCB substrate adopts high-Tg (≥170℃) ceramic-filled copper-clad laminate or silicon nitride (Si3N4) AMB substrate—silicon nitride substrate has gradually replaced traditional aluminum oxide (Al2O3) substrate due to its excellent thermal conductivity, high hardness, and thermal stability, enabling it to withstand greater thermomechanical stress. These substrates exhibit excellent dimensional stability and thermal conductivity, effectively reducing thermal resistance. SiC devices, including power MOSFETs and diodes, are all AEC-Q certified, ensuring stable performance in the -40℃~+175℃ wide temperature range. The PCB surface is treated with ENIG (Electroless Nickel Immersion Gold) process to improve the oxidation resistance and mechanical strength of solder joints, ensuring reliability after thousands of thermal cycles. Furthermore, professional three-proof coating (conformal coating) is applied to the PCBA to resist moisture, salt spray, and chemical corrosion in the engine compartment, while enhancing insulation performance. For high-power SiC modules, nano-silver sintering technology is adopted for the connection layer (sintered at temperatures below 250℃ and pressures of 5~20MPa), which forms a high-density, high-thermal-conductivity bonding layer, reducing thermal resistance by 95% and improving reliability by more than 5 times compared with traditional soldering.

　　3. Precision Manufacturing Process for SiC Applications. Relying on more than 50 sets of high-precision CNC machine tools and advanced SMT equipment, Szchaopin achieves micron-level precision control in SiC device placement. For SiC modules with high pin density and BGA packaging, 3D AOI and X-Ray inspection technologies are employed to strictly control solder joint quality, ensuring the BGA void rate is ≤5% to meet the high thermal conductivity requirements of SiC devices. In the soldering process, a high-precision reflow soldering process with real-time furnace temperature curve monitoring is adopted to avoid device damage caused by excessive temperature. A full-process traceability system is established, integrating component batches, placement parameters, soldering data, and inspection results of each PCBA into the MES system, realizing full-process controllability. For high-power SiC module assembly, laser welding technology is adopted for the connection of electrode terminals, with specialized plastic insulators providing structural support during welding to ensure tight contact between copper terminals and reliable welding quality. For embedded SiC chip packaging, Cu clip bonding technology is adopted to enhance current-carrying capacity and reduce thermal resistance, further unlocking the performance potential of SiC devices.

　　4. Comprehensive and Strict Reliability Testing. Szchaopin has built a full-cycle testing system tailored for 800V SiC PCBA, simulating actual operating conditions to conduct multi-dimensional reliability verification. Key tests include: high and low temperature cycle testing (-40℃~+175℃, 2000 cycles) to verify thermal cycling resistance; high-voltage withstand testing (≥1500V DC) to ensure insulation safety margins; EMC testing to confirm compliance with automotive EMI standards, effectively suppressing interference from high-speed switching of SiC devices; vibration and impact testing (10~2000Hz, 30g acceleration) to verify mechanical robustness. Additionally, referring to the T/CASAS 041—2025 standard, a dedicated inductive load aging screening test is conducted, simulating inverter operating conditions to screen out early failure devices. A 48-hour full-load functional aging test is also performed to verify the stability of SiC device performance and PCBA circuit reliability under long-term high-power operation. For PCBA applied in OBC systems, additional efficiency testing is conducted to ensure the comprehensive conversion efficiency exceeds 96% and the peak conversion efficiency reaches over 97%, meeting the high-efficiency requirements of 800V charging systems.

　　Practical Value and Industry Empowerment. In a mainstream new energy vehicle enterprise's 800V main inverter project, the SiC PCBA customized by Szchaopin has achieved excellent performance in practical applications. Test data shows that the PCBA effectively reduces the stray inductance of the power loop by 75%, reducing SiC switching losses by 30% compared with traditional designs—consistent with industry data that full SiC MOS solutions can reduce switching losses by up to 70% compared to pure Si IGBT/FRD. Under continuous high-power operation, the maximum temperature rise of the SiC device junction is controlled within 40℃, ensuring stable operation efficiency. After 2000 high and low temperature cycles and 1000-hour constant temperature and humidity testing, no solder joint failures or insulation degradation occurred. The PCBA supports a maximum charging power of 600kW, reducing the vehicle's fast charging time to less than 20 minutes. This solution not only meets the ISO 26262 functional safety standard but also helps customers improve the overall efficiency of the electric drive system to 99%, extending the vehicle's cruising range by more than 3% and shortening the product development cycle by 40%. Moreover, the PCBA design is compatible with the integrated layout requirements of "800V DC-DC converter + high-voltage battery pack + SiC motor controller", contributing to a 20% reduction in the volume and 15% reduction in the weight of the vehicle power system.

　　Conclusion. The popularization of 800V high-voltage platforms and the wide application of SiC devices are driving a profound transformation in the new energy vehicle industry—an 800V high-voltage pure electric vehicle requires more than 100 SiC devices, and the market demand is growing exponentially. As a core component, 800V SiC PCBA's reliability and performance directly determine the competitiveness of high-voltage vehicles. Szchaopin's 800V SiC device PCBA solution, built on precision manufacturing, advanced material technology, and strict quality control, accurately addresses the core pain points of high-voltage insulation, thermal management, and EMI interference in 800V systems. In the future, with the large-scale mass production of 8-inch automotive-grade SiC chips driving cost reduction, Szchaopin will further deepen collaborative R&D with SiC chip manufacturers, integrate digital twin technology to optimize PCBA design and testing processes, and develop solutions compatible with 1000V+ high-voltage platforms and 1700V-class SiC devices, providing more efficient and reliable core support for the high-quality development of the new energy vehicle industry and promoting the popularization of SiC technology in mid-to-low-priced models.