INFAC Corporation has launched a new 800V battery pack design for electric vehicles (EVs) that integrates a high-power 800V-to-48V isolated and regulated DC-DC converter.
Incorporating Vicor’s high-density DC-DC converters and regulators, the design improves vehicle performance, power efficiency and boosts range through the reduction of high-voltage cables and connectors.
Rather than treating the DC-DC conversion stage as a distributed standalone subsystem, INFAC designed the power to be stepped down at the source for SELV distribution throughout the vehicle. The streamlined approach enables cleaner, flexible, more modular 48V zonal designs for various EV platforms without displacing battery cells nor reducing vehicle range.
Internalising DC-DC conversion
High voltage DC-DC converters are typically mounted outside the high-voltage (800V or 400V) battery assembly system (BAS), requiring additional safety and thermal management systems. The EV motor and inverter systems demand hundreds of kilowatts of power and require high-voltage wiring harnesses, brackets and enclosures. Other powertrain subsystems and body and chassis electronics require 3.5–12kW, and can be easily powered from a 48V SELV zonal power distribution network.
Physically separating the high-voltage source and DC-DC conversion power system unnecessarily duplicates power distribution and management systems, which wastes space, weight and cost and doubles the liquid cooling systems required.
INFAC identified that the battery pack already incorporates a robust liquid cooling system for managing thermal loads. By integrating the high voltage DC-DC converter inside the battery and leveraging the existing infrastructure, INFAC eliminated the separate cooling system which traditionally resides outside the battery pack for the DC-DC converter. This departs from conventional “silver-box” design approaches by positioning the battery pack as a central, intelligent power hub rather than a passive energy source.
The change was made using Vicor high-density BCM6135 DC-DC converters and PRM3735 regulators, which provide HV-to-48V conversion and regulation and enable a high-power, fully isolated and regulated bus for the zonal architecture.
Previously, housing the DC-DC conversion function inside the battery pack was impractical as size constraints forced designers to grapple with power management issues, electrical isolation, safety requirements and power module packaging robustness.
Benefits of battery-integrated DC-DC conversion
INFAC observed several benefits that increased system-level performance, after co-locating the DC-DC converter within the battery pack.
By leveraging the battery’s liquid cooling network, the power module eliminates redundant coolant loops and reduces thermal interfaces. High-voltage cable length and thickness are also reduced, simplifying high-voltage harness routing and layout.
The approach also requires fewer brackets, enclosures and cooling components, therefore reducing both cost and weight. Meanwhile, minimising connections and cooling paths reduces leak points and electrical failure risks.
The manufacturing process is also faster and more consistent, as there are fewer external interfaces to contend with.
