Environmental, economic and social factors are affecting the choice of future vehicle design and powertrain. Given the carbon dioxide (CO2) emissions policy, tax incentives and the development of charging infrastructure, the strategic layout of the power system will undergo significant evolution in the short and long term. Power semiconductors are key components of powertrain systems for electric vehicles (EVs), hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). It is understood that the semiconductor content of each electric vehicle may exceed $750 compared to the average semiconductor content of $330 in a fuel vehicle, most of which is powered by the main inverter, car charger and DC-DC converter. Equipment occupied. As the number of electric and electric vehicles (HEVs and PHEVs) increases, so does the demand for complex power electronics solutions that will reduce power loss, system weight and total cost.
Power devices such as MOSFETs and IGBTs based on silicon (Si) technology currently play an important role due to the maturity of technology, manufacturability and the establishment of a supply chain. In general, MOSFETs cover the low voltage (<200V) field, while IGBTs contribute to high voltage (>600V) related applications. In terms of packaging, power discrete packages such as transistor outline package (TO), small outline transistor package (SOT), quad flat no-lead plastic package (PQFN) and high current application (TOLL) packages, they are low power (< 5kW) has been well applied in the field of application. However, for high power (> 50 kW) subsystems, a molded or frame based power module is required. The portfolio of multiple power equipment suppliers includes discrete, molded and frame modules in configurations such as single-switch, half-bridge, full-bridge and three-phase designs.
As electric vehicle (xEV) solutions increase, so does the cost ($/kW) and power density (kW/Kg or kW/l) requirements for power electronics. Currently, the cost control is about $5/kW and the power density is about 12 kW/liter. By 2035, these costs are expected to reach $3/kW and 60 kW/L. Existing semiconductor device technologies, packaging technologies, and system-level architectures are unable to achieve these future roadmap goals. This trend may be split into two paths: a fully integrated solution designed by electric motors and power electronics, or a single power management converter to manage the entire vehicle's power.
To meet the requirements of automotive and system manufacturers, semiconductor suppliers need to provide superior solutions in multiple areas. From a semiconductor technology perspective, silicon power devices will continue to play a key role as performance improves. As a result, new wide bandgap materials such as silicon carbide (SiC) and gallium nitride (GaN) are expected to play a larger role in the coming decades, especially in high power traction inverters and medium power converter applications. As shown in Table 1, these new materials offer better thermal and electrical performance than traditional silicon devices, but present challenges in manufacturability, integration, and cost. In order to maximize the potential benefits of wide bandgap semiconductor materials, advanced components, converter topologies, and integrated circuits need to be jointly developed.
At the package level, high temperature performance, integration and reliability are the three major drivers of innovation. For high-temperature performance of power discretes and modules, better thermal interface materials (TIM), novel substrate concepts, and improved packaging techniques are required for design. In addition, new materials require constant innovation to provide better mechanical stability and robustness, as well as improved bonding mechanisms to better withstand extended power and temperature cycling. As silicon carbide and GaN devices become more popular, but because they cannot completely replace silicon devices, current packaging solutions need to be optimized. For example, with the introduction of wide bandgap materials and the reduction in the number of passive components, significant space savings will be realized, enabling package-level integration solutions with gate drivers and filters.
At the same time, current inverter and converter architectures will increase efficiency due to incremental improvements in existing silicon devices. In order to provide further functionality, such as hybrid strategies for integrating SiC rectifiers or GaN transistors, and efficient design such as distributed architectures will be expected to meet market demands. In the future, in order to fully exploit the potential of wide bandgap devices, further innovation in circuit design, combined with high frequency switches, soft switches and resonant switches, will provide a more efficient, higher power density solution. In addition, the market trend of integrating motors and power converters will present challenging packaging requirements, primarily in terms of mechanical, thermal and electrical performance requirements. For SiC and GaN devices, current-packaging techniques can limit performance by stray inductance that causes switching losses and parasitic capacitance that causes common-mode currents.
From the perspective of trend development, SiC and GaN will be the main force of power semiconductors. With the continuous improvement of high temperature performance, integration and reliability, the active and passive components inside the car will gradually increase. For packaging technology, to follow these steps, it is undoubtedly to achieve technological innovation.