The fundamental source of thermal stress in a 22 kW wireless power transfer (WPT) pad is the aggregate of electromagnetic power losses distributed across multiple physical components operating at high-frequency resonance, typically around 85 kHz. As documented by Harbin Institute of Technology (2022), even at 6.6 kW, the calculation of internal resistance of litz coils, core losses, and eddy-current losses in the shielding aluminum plate must be performed with temperature-dependent material properties — a complexity that scales severely with increasing power.

Resistive I²R losses in the litz-wire coils represent the largest single heat source. Increasing coil turns to maintain coupling at misaligned positions — a common requirement in real-world EV parking scenarios — directly increases litz-wire resistance and therefore I²R heating. At 22 kW, the total dissipated power in the pad assembly is roughly proportional to losses at lower powers scaled by the square of the current increase.

Ferrite core losses present a particularly dangerous failure mode. Research from Southwest University of Science and Technology (2021) shows that at 85 kHz operation and high flux density, MnZn ferrite exhibits non-negligible core loss. As frequency and flux density increase with power level, ferrite loss density rises steeply — creating localized hot spots that can exceed the Curie temperature threshold of approximately 200–230°C for typical power ferrites, triggering irreversible permeability degradation and accelerating thermal runaway. Learn more about materials innovation intelligence on PatSnap.

An important and frequently underestimated heat source is the electromagnetic shielding infrastructure itself. Solid aluminum shielding plates generate significant eddy-current losses that reduce system efficiency and produce localized heating. Research from the State Grid Electric Power Research Institute (2022) shows that substituting a mesh-perforated aluminum plate reduces eddy currents in targeted regions, but the thermal implications of this redistribution must be explicitly modeled. The interaction between shielding design and thermal performance means these two subsystems cannot be optimized independently in a 22 kW pad.

Synthesising over 15 papers and patents, the engineering picture at 22 kW is clear: this power class represents a qualitative shift where every design decision has thermal consequences, and no single mitigation strategy is sufficient on its own. The patent landscape analytics available through PatSnap reveal that the most successful approaches combine architectural choices (three-phase coil distribution) with active cooling (liquid channels) and validated through two-way coupled simulation.

The IEC standards framework for wireless EV charging (IEC 61980 series) and the SAE J2954 standard define interoperability requirements that constrain pad geometry — making the thermal problem harder to solve through dimensional changes alone. Engineers must work within fixed footprint and air gap tolerances while managing heat fluxes that demand active cooling.

The trend across all contributing institutions points toward co-simulation environments that simultaneously resolve electromagnetic field distributions, power loss densities, and resulting temperature fields in a single coupled workflow — moving away from sequential, decoupled design processes that consistently underestimate peak temperatures at elevated power levels. See how R&D teams use PatSnap to accelerate this design process.