In the race for fast charging in new energy vehicles, the heat generated by massive currents and voltages is bound to damage traditional electronic components, and conventional heat dissipation solutions are no longer sufficient. Although copper and aluminum alloys have good thermal conductivity, they are also electrical conductors, requiring additional insulation layers that actually hinder heat transfer. In this context, a material that combines the dual characteristics of “superior thermal conductivity” and “perfect insulation” has emerged—the diamond heat sink.
Heat Transfer Accelerator
Diamond’s ultra-high thermal conductivity (20 W/m·K) stems from its perfect crystal structure. Within a diamond crystal, carbon atoms are tightly packed in a tetrahedral arrangement, forming a rigid lattice. When heat is introduced, lattice vibrations (phonons) can propagate with extremely low resistance, achieving heat transfer speeds of 30–100 km/s—more than five times the speed of phonons in copper.
Electric Field Stabilizer
Under high-voltage conditions of 1,000 V, conventional insulating materials are prone to breakdown. Diamond’s wide bandgap (5.SeV) enables it to withstand a breakdown electric field strength of 10 MV/cm—33 times that of gallium nitride and 33 times that of silicon. This ensures the safe operation of electronic components in high-voltage environments.
Thermal Expansion Adapter
Diamond’s coefficient of thermal expansion is only 0.8 × 10⁻⁶, which is comparable to that of silicon (26 × 10⁻⁶ K) and silicon carbide (42 × 10⁻⁶ m). This property prevents diamond substrates from separating from semiconductor materials during drastic temperature changes, ensuring long-term stability.
In megawatt fast-charging systems, diamond heat sinks are strategically deployed at three key locations:
Power module heat sink (the core of the charging station)
In the power conversion module of a charging station, insulated-gate bipolar transistors (IGBTs) and metal-oxide-semiconductor field-effect transistors (MOSFETs) are the most critical power devices.
Diamond Solution:
Diamond-Substrate MOSFETs: Researchers have developed a diamond-substrate-based MOSFET structure, forming a hydrogen-terminated layer on the diamond substrate and placing a gate dielectric layer and gate electrode on the surface.
Innovative Packaging Technology: Heat is efficiently conducted to the heat sink via large-area exposed pads, with 95% of the heat transferred directly to the liquid cooling system.
Battery Pack Liquid Cooling System (Vehicle Core)
Faced with the immense heat generated by 1,000 A high-current charging, new energy vehicles have redesigned their liquid cooling solutions; however, the addition of diamond materials can further improve heat dissipation efficiency by 90%.
Diamond Solutions:
Diamond-Coated Battery Tabs: A 1-micrometer-thick diamond film is deposited on the battery tabs (positive and negative terminals) to reduce contact resistance while accelerating heat dissipation.
Diamond Thermal Interface Layer for Liquid-Cooling Plates: Diamond thermal interface pads are added between the liquid-cooling plates and battery modules, with a thermal conductivity as high as 3.6 W/mK.
3D Diamond Heat Dissipation Frame: Structural components of the battery pack are manufactured using composite materials filled with diamond micropowder, balancing structural strength and thermal management.
Diamond Substrates for 3GaN Devices (Core of Power Conversion)
For gallium nitride (GaN) power devices in onboard chargers and electric drive inverters, diamond substrates demonstrate remarkable performance:
Diamond Solutions:
GaN-on-Diamond Technology: Transferring GaN devices onto diamond substrates via direct bonding technology
Experiments show that, at the same power density, diamond-based GaN devices operate 40% cooler than silicon carbide-based ones, and device lifespan can be extended by 10 times.
At high frequencies of 10 GHz, output power can reach over 10 W/mm, far surpassing the performance of traditional materials.
As diamond processing technologies mature and costs decline, this material—formerly specialized for the aerospace sector—is now making a major impact in the new energy vehicle industry. It is not only the key to breaking the “high-temperature curse” of megawatt flash charging but also a crucial technological pillar driving electric vehicles to comprehensively surpass internal combustion engine vehicles.
