Conductive 1K Epoxy Adhesive for Low-Stress Solar Cell Connections

The patent employs a composite adhesive formulation combining epoxy resin with conductive filler particles (silver, aluminum, or carbon), creating a material that simultaneously provides mechanical bonding strength and electrical conductivity. The epoxy matrix contributes high mechanical strength and adhesion, while the conductive filler network ensures low electrical contact resistance, resolving the contradiction between mechanical strength and connection reliability.

The patent optimizes the concentration, size distribution, and morphology of conductive filler particles within the adhesive formulation. By controlling these parameters—specifically using 20-80 wt% conductive filler with optimized particle size distributions—the formulation achieves a percolation network that minimizes electrical contact resistance and reduces energy loss while maintaining electrical connectivity.

The patent modifies the adhesive formulation by incorporating functional additives and optimizing the resin-filler matrix composition to adjust the coefficient of thermal expansion (CTE) of the adhesive. This CTE matching between the adhesive and bonded substrates (solar cells and interconnectors) reduces differential thermal expansion, thereby minimizing thermal stress and improving thermal stability during temperature cycling.

The patent employs a heterogeneous filler distribution strategy where conductive filler particles are non-uniformly distributed within the epoxy matrix. Higher filler concentrations are localized in regions requiring enhanced conductivity (near contact points), while other regions maintain lower filler content to preserve mechanical strength and adhesion properties. This spatial variation in filler quality resolves the contradiction between conductivity and strength.