OBC charger thermal solution

   Because the integrated and multi-functional vehicle charger will generate additional power load due to the conversion of electric energy, however, AC / DC load (charging mode) and DC load (driving mode) do not occur at the same time. Vehicle charger is an essential core component of new energy vehicles, and the thermal management of vehicle charger has become more and more serious.

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    This makes the thermal design engineers usually let multiple thermal loads in a multi-functional vehicle charger share the same heatsink, the shell of the vehicle charger hardware mold, to reduce the overall size, weight and cost. All electronic components of the vehicle charger need to be packaged in this closed shell environment to prevent environmental pollution. This requires that these electronic devices, chips, MOSFETs, etc. with huge heat generation must contact the inner wall of the shell of the metal mold to effectively realize heat transfer and heat dissipation.

     At present, the most common thermal management material solution is to use thermal insulation sheet or thermal insulation sheet + thermal silicone grease. The thermal insulation sheet has the functions of insulation, voltage resistance and tear resistance. The breakdown voltage can reach more than 6kV, meeting the needs of the vehicle. The extremely low thermal resistance can quickly transfer the heat generated by MOS to the shell radiator of the vehicle charger. Phase change insulating materials can also be used directly. The phase change coating is solid at normal temperature. When the working temperature reaches its phase change temperature, it will change from solid state to fluid state.

   When under the external pressure, the phase change material of the fluid state can fully infiltrate the interface (heat source and heat sink surface) to minimize the contact thermal resistance of the interface, so as to achieve the best heat transfer.