High-Voltage Resistance of High-Power Application in New-Energy Vehicles
By Kuang Mei Juan & Wang Jun, Shenzhen Kinwong Electronic Co Ltd, Shenzhen, China
With the automotive industry diversifying, new-energy vehicles such as EVs and hybrids are developing very quickly, and the application of high power is inevitable. PCB, as the critical electric interconnecting component, plays a vital role in automobile assembly line and its high power application requires high-voltage resistance (≥1,000V).
Kinwong, a professional and experienced PCB manufacturer, has accumulated a range of high voltage resistance experience for automotive PCBs based on manufacturing processes and customer feedback, and has performed many DOEs during the past 20+ years.
Based on Ishikawa, Kinwong performed the DOE for high voltage resistance, the main factors of which were different base material, dielectric thickness, conductor spacing and solder-mask thickness. Qualification boards with dedicated test patterns were used to check base material and corresponding prepregs; the influence of conductor spacing and solder-mask thickness was also checked by qualification boards with specified base material and base copper. There were four types of unique test patterns (trace-to-trace, trace point-to-trace point, annular ring-to-annular rings, and annular ring-to-trace) to validate the conductor spacing.
The conclusions below are based on the findings of DOEs.
For Stack-up Design:
Three sheets of prepreg (including a CORE) is a must.
Dielectric thickness≥0.09mm (Remark: 500V per 0.025mm dielectric thickness).
For Base Material Use
Middle or high Tg material is preferred.
For S/M Thickness Requirement
Printing twice ensures thick S/M thickness on the whole board, even at the knee of the conductor.
For Profiling Method Use:
If copper images applying Hi-pot on internal layers to outline≤1mm, that area should be routed. V-cut is not allowed there, because delamination will happen to the prepreg layer when de-panelling at these v-cut lines.
For Engineering Design
Hi-pot requirement vs. copper image spacing below (including copper image to outline on internal and external layers) is for your reference.
Finally, for high-voltage application, Kinwong can supply general heavy copper boards or special ones with POFV, buried and blind vias. Cu inlay or pure copper layer sandwiching and metal PCBs are all available. For heavy copper boards, the maximum base copper is 6oz, layer count reaches maximum 18L and final board thickness is maximum 5.0mm for mass production.
Kinwong will be exhibiting on booth 424 at Electric & Hybrid Vehicle Technology Expo Europe.