Powering the Future: Performance Is Won in Assembly
Connect the Dots: Total Value Manufacturing Solutions
Fresh PCB Concepts: IPC-6012 Class 3 and High-reliability PCB Manufacturing
EV reliability is often discussed at the vehicle or system level, but many of the most persistent failures begin at the materials level. Semiconductor devices, ceramic substrates, die attach materials, wire bonds, clips, thermal interface materials, laminates, coatings, seals, and coolants define the electrical, thermal, and mechanical limits of the hardware.
Once EV architectures move toward higher voltages, switching speeds, and power density, and longer service life, those materials are pushed harder, and small weaknesses can turn into large field problems. Wide-bandgap devices can raise efficiency and reduce mass, but they also place more stress on gate oxides, passivation, interconnects, insulation systems, and cooling paths.
Figure 1: Examples of materials comprising a power module (Semikron-Danfoss).4
This matters because materials failures rarely stay local. A single degraded interface can raise thermal resistance, increase current crowding, alter switching behavior, damage neighboring parts, and shorten the life of the assembly. In the field, the result may appear as reduced range, charging interruption, inverter shutdown, isolation fault warnings, intermittent behavior, derating, or complete module failure. Current crowding occurs when electrical current does not flow uniformly through a conductor, but instead concentrates in localized regions such as edges, corners, contact interfaces, or narrowed geometries.
This effect increases local current density, even when overall current levels appear to be within design limits. In EV systems operating at 400–800 V and at high current, it becomes even more severe because small design imperfections get amplified and lead to faster degradation. In his presentation at the EV Special Session at APEX EXPO 2025, Dr. Olaf Schoenfeld noted that material interfaces are a common source of reliability issues due to improper surface preparation and cleanliness.5 In short, the road to reliability starts well before final assembly; it starts with what the system is made of.
To continue reading this article, which appeared in the June 2026 SMT007 Magazine, click here.
