Breakthrough in High-Power EV Modules: 1200A IGBT Design Achieves 800V Capability
In a significant leap forward for electric vehicle (EV) power electronics, a team of researchers has successfully developed a next-generation IGBT power module capable of handling 1,200 amperes at a bus voltage of 800 volts within the widely adopted EconoDUAL package. This new design, detailed in a recent publication in the Journal of Power Supply, represents a pivotal advancement in power density, thermal management, and electrical performance, directly addressing the growing demands of high-performance electric drivetrains and fast-charging infrastructure.
As the global automotive industry accelerates its transition to electrification, the pressure on power electronics to deliver higher efficiency, faster switching, and greater reliability has intensified. Central to this evolution is the Insulated Gate Bipolar Transistor (IGBT), a semiconductor device that acts as the electronic switch controlling the flow of current between the battery and the motor. For years, the industry has relied on standardized packaging formats such as the EconoDUAL, originally designed for lower current and voltage levels. However, the emergence of 800-volt architectures—championed by brands like Porsche, Hyundai, and Lucid for their ability to enable ultra-fast charging—has pushed conventional designs to their limits. The primary bottleneck has been the inherent parasitic inductance within the module’s internal layout, which can cause destructive voltage spikes during rapid switching, limiting both the usable voltage and the maximum current.
The research team, led by Hui Xiaoshuang and Ning Puqi from the Institute of Electrical Engineering at the Chinese Academy of Sciences, has now overcome this challenge with an innovative three-dimensional layout. Their approach marks a departure from the traditional two-dimensional planar design, where power chips are placed side-by-side on a single Direct Bonded Copper (DBC) substrate. This conventional method, while robust, creates long current paths and significant loop areas, resulting in high parasitic inductance—typically around 15 nanohenries in existing commercial modules. This inductance not only restricts switching speed but also generates electromagnetic interference (EMI) and increases switching losses, all of which compromise system efficiency and power density.
The core of the team’s innovation lies in the adoption of a stacked DBC architecture. Instead of a single DBC layer, the new module employs two DBC substrates, one positioned above the other, with the power chips distributed across both levels. This vertical stacking allows for a dramatic reduction in the physical loop area of the main power circuit. By carefully arranging the chips so that the current flows in opposite directions on the upper and lower layers, the design leverages the principle of mutual inductance cancellation. Essentially, the magnetic fields generated by the opposing currents partially cancel each other out, leading to a substantial net reduction in overall parasitic inductance.
The researchers utilized an automated layout optimization algorithm to determine the most efficient placement of the six IGBT and six diode chips within the constrained space of the EconoDUAL package. Each IGBT chip has a current rating of 200 amperes, and when paralleled, they achieve the target 1,200-ampere capacity. The diodes, similarly rated, ensure balanced performance across the half-bridge configuration. The final 3D model was analyzed using advanced electromagnetic simulation software, which predicted an internal parasitic inductance of just 5.89 nanohenries. This represents a remarkable 58 percent reduction compared to the 10.16 nanohenries measured in a conventional 2D layout for the same package size. This level of inductance suppression is critical for stable operation at 800 volts, as it prevents the voltage overshoot that could otherwise damage the semiconductor chips during turn-off events.
To validate the electrical performance of their prototype, the team conducted rigorous double-pulse testing, a standard industry method for evaluating the dynamic behavior of power modules. In these tests, the lower switch of the half-bridge is subjected to a high-current pulse while the upper switch is held in a blocking state. The test was performed at the full 800-volt bus voltage, with a peak pulse current of 1,200 amperes, simulating the extreme conditions found in a high-power EV inverter. The results were unequivocal: the module passed the test with flying colors, demonstrating clean switching waveforms and no signs of electrical overstress. The successful completion of this test under high-temperature conditions further confirmed the robustness and reliability of the design, proving that the high power density did not come at the expense of electrical integrity.
A critical concern in any high-power module is thermal management. Packing more current into the same physical footprint generates more heat, which must be efficiently dissipated to prevent overheating and ensure long-term reliability. The researchers addressed this challenge by integrating a high-performance PinFin water-cooled heatsink directly onto the bottom of the module. PinFin heatsinks feature an array of small, fin-like protrusions that dramatically increase the surface area in contact with the coolant, enhancing heat transfer efficiency. Computational Fluid Dynamics (CFD) simulations were used to model the electro-thermal-fluid coupling within the module, predicting a maximum junction temperature of approximately 150 degrees Celsius under full load, well within the safe operating range for modern IGBTs.
To verify these simulation results, the team performed transient thermal resistance testing on the physical prototype. This method involves applying a high heating current to the device, then rapidly switching it off and measuring the rate at which the junction temperature cools down. By analyzing this cooling curve, the thermal resistance from the semiconductor junction to the cooling water (known as the junction-to-water thermal resistance) can be accurately determined. The measurements revealed an IGBT thermal resistance of 0.084 K/W and a diode thermal resistance of 0.124 K/W. These values are comparable to those of a commercially available 1,200-volt, 900-ampere module in the same EconoDUAL package, indicating that the new, higher-current design does not suffer from degraded thermal performance. This parity is a testament to the effectiveness of the PinFin heatsink and the overall thermal design, ensuring that the gains in electrical performance are matched by equivalent gains in thermal capability.
The implications of this research are far-reaching. By enabling a 1,200-ampere module in a standard EconoDUAL package, the design offers a clear path for EV manufacturers to increase the power output of their drivetrains without having to redesign their entire inverter or cooling systems. This backward compatibility is a significant advantage, as it allows for incremental upgrades and reduces development costs. Furthermore, the ability to operate reliably at 800 volts opens the door to faster charging, reduced cable weight, and improved overall system efficiency, all of which contribute to a better driving experience and longer vehicle range.
The success of this project is a product of a multidisciplinary approach, combining expertise in semiconductor physics, power electronics, mechanical design, and thermal engineering. The team’s use of automated layout optimization tools highlights a growing trend in the field, where complex design problems are solved not by intuition alone, but by sophisticated algorithms that can explore vast design spaces to find optimal solutions. This approach not only accelerates the development cycle but also ensures that the final design is truly optimized for its intended performance metrics.
The work also underscores the importance of fundamental research in driving industrial innovation. While the automotive industry often focuses on end-user features like range and acceleration, the real breakthroughs frequently occur in the underlying technologies, such as power modules. This research, funded by the National Key Research and Development Program of China and the CAS Youth Multi-discipline Project, exemplifies how strategic investment in core technologies can yield tangible benefits for the entire EV ecosystem.
Looking ahead, this new IGBT module design sets a new benchmark for power density and performance. It paves the way for the next generation of high-performance electric vehicles, from sports cars to heavy-duty trucks, that demand unprecedented levels of electrical power. As the technology matures and moves from the laboratory to mass production, it is likely to be adopted by a wide range of manufacturers seeking to gain a competitive edge in the rapidly evolving EV market. The principles demonstrated in this work—3D stacking, parasitic inductance minimization, and advanced thermal management—are not limited to IGBTs and could be applied to other wide-bandgap semiconductors like silicon carbide (SiC), which are increasingly being used in high-end EVs.
In conclusion, the development of this 1,200A, 800V IGBT power module is a landmark achievement in power electronics. It solves a critical engineering challenge by rethinking the internal architecture of a standard package, achieving a dramatic reduction in parasitic inductance while maintaining excellent thermal performance. The successful electrical and thermal testing confirms the viability and robustness of the design. This work not only advances the state of the art in power module technology but also provides a practical solution that can be readily integrated into future EV platforms, accelerating the pace of innovation in the automotive industry.
Hui Xiaoshuang, Ning Puqi, Fan Tao, Guo Xinhua, Fu Jinyuan, Huang Ke, University of Chinese Academy of Sciences, Institute of Electrical Engineering, Chinese Academy of Sciences, Huaqiao University, Zhejiang Xinfeng Technology Co., Ltd, Journal of Power Supply, DOI 10.13234/j.issn.2095-2805.2024.3.72