Back-Contact Solar Cell Bus Bar Crossings for Lower Wiring Resistance

The patent applies dimensionality change by forming bus bar electrodes that extend in the longitudinal direction (third dimension relative to the substrate plane) to intersect with finger electrodes. This three-dimensional configuration allows current collection from multiple directions and reduces wiring resistance without increasing the contact area on the substrate surface, thereby resolving the contradiction between minimizing contact area and reducing wiring resistance.

The patent segments the electrode system into finger electrodes for current collection and bus bar electrodes for current transport. The bus bar electrodes are divided into multiple segments extending in the longitudinal direction, each intersecting with finger electrodes at different positions. This segmentation allows distributed current collection points, reducing the total path length and resistance while maintaining small contact areas.

The patent transitions from a two-dimensional peripheral arrangement to a three-dimensional configuration where bus bar electrodes extend in the longitudinal direction and intersect with finger electrodes across the substrate. This dimensional change allows current collection from both sides of the substrate, effectively halving the maximum finger electrode length and reducing wiring resistance without significantly increasing device complexity.

The patent applies local quality by positioning bus bar electrodes at specific intersection points with finger electrodes rather than uniformly across the substrate. The bus bar electrodes are formed to extend in the longitudinal direction at regions where they intersect with transverse finger electrodes, creating localized current collection zones that optimize the balance between simplicity and electrical performance.

The patent uses the longitudinal extension of bus bar electrodes in the third dimension to achieve spatial separation between opposite polarity electrodes. By forming N-type and P-type bus bar electrodes to extend in opposite directions or at different heights, the patent prevents contact between opposite polarity electrodes without requiring insulator films, thereby maintaining manufacturing precision while avoiding additional production steps.

Instead of using insulator films to prevent contact between opposite polarity electrodes (the conventional approach), the patent inverts the approach by using the geometric configuration and directional extension of bus bar electrodes themselves to prevent contact. The bus bar electrodes are formed to naturally avoid contact with opposite polarity electrodes through their longitudinal extension and intersection geometry, eliminating the need for insulator films.