Tesla continues to improve its Solar business. The company is constantly evolving and is applying for new patents. Yesterday, we familiarized ourselves with its new patent 'External electrical contact for solar roof tiles'. In addition to this patent, Tesla also filed for another 'Solar roof tile spacer with embedded circuitry'.

International Filing Date: 31.07.2019
Publication Date: 06.02.2020

The photovoltaic roof tile module can include a first photovoltaic roof tile and a second photovoltaic roof tile positioned adjacent to each other and a spacer coupled to and positioned between the first and second photovoltaic roof tiles. A respective photovoltaic roof tile can include a front glass cover and a back cover, which includes a glass substrate and a pre-laid circuit attached to the glass substrate. The pre-laid circuit is electrically coupled to the plurality of photovoltaic structures. The spacer can include a thermal plastic body and one or more metallic strips embedded within the thermal plastic body, and both ends of a respective metallic strip extend beyond edges of the thermal plastic body to facilitate electrical coupling between pre-laid circuits of the first and second photovoltaic roof tiles.

This disclosure is generally related to photovoltaic (or“PV”) roof tile modules. More specifically, this disclosure is related to spacers used for mechanically and electrically coupling adjacent PV roof tiles within a multi-tile module.

A respective photovoltaic structure can include a first edge busbar positioned near an edge of a first surface and a second edge busbar positioned near an opposite edge of a second surface, and the plurality of photovoltaic structures can be arranged in such a way that the first edge busbar of a first photovoltaic structure overlaps the second edge busbar of an adjacent photovoltaic structure, thereby resulting in the plurality of photovoltaic structures forming a cascaded string with the plurality of photovoltaic structures coupled to each other in series.

In a further variation, positive and negative polarities of the cascaded string are respectively coupled to first and second metallic strips embedded within the thermal plastic body.
The thermal plastic body can include:

• polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE);
• can be formed using a plastic molding technique;
• can include a base and two wings extending from the base in opposite directions. A respective wing of the spacer can be positioned between the front and back covers of a respective photovoltaic roof tile, and the ends of the metallic strips can extend beyond the edges of the wings.

In a further variation, the base of the spacer can include a groove extending along a longitudinal axis on its sun-facing surface, thereby creating a visual effect of a gap between the first and second photovoltaic roof tiles. On this embodiment, the pre-laid circuit can include metallic strips attached to the glass substrate via conductive paste or metallic traces printed onto the glass substrate or a respective metallic strip can include Cu.

Embodiments of the invention solve at least the technical problem of enabling low-cost and reliable electrical interconnections among solar roof tiles within a multi-tile module. More specifically, embedded circuits can be used to electrically connect the multiple tiles within a multi-tile module. In some embodiments, an embedded circuit can include metallic strips or traces that are pre-laid onto the interior surface of the back cover of the multi -tile module. To facilitate inter-tile electrical coupling, a specially designed tile spacer that includes at least a section of the embedded circuit can be inserted between two neighboring solar roof tiles. More specifically, a circuit section (e.g., a piece of metallic strip) can be embedded inside the bottom layer of the tile spacer with both ends of the circuit section extruding out of the tile spacer. The extruded ends can be coupled to pre-laid circuit on the back covers, thus facilitating electrical coupling between adjacent tiles.

FIG. 2 shows the perspective view of an exemplary photovoltaic roof tile, according to an embodiment.

Solar cells 204 and 206 can be hermetically sealed between top glass cover 202 and backsheet 208, which jointly can protect the solar cells from various weather elements. In the example shown in FIG. 2, metallic tabbing strips 212 can be in contact with the front-side electrodes of solar cell 204 and extend beyond the left edge of glass 202, thereby serving as contact electrodes of a first polarity of the PV roof tile. Tabbing strips 212 can also be in contact with the back of solar cell 206, creating a serial connection between solar cell 204 and solar cell 206. On the other hand, tabbing strips 214 can be in contact with front-side electrodes of solar cell 206 and extend beyond the right edge of glass cover 202, serving as contact electrodes of a second polarity of the PV roof tile.

FIG. 10 shows a partial cross-sectional view of a multi-tile module, according to one embodiment.

Multi-tile module 1000 includes solar roof tiles 1002 and 1004 coupled to each other by tile spacer 1006. Each solar roof tile (e.g., solar roof tile 1004) can include a front cover 1012, a back cover 1014, an encapsulant layer 1016, a cascaded string 1018, and a pre-laid circuit 1020. More specifically, pre-laid circuit 1020 is attached to back cover 1014. Moreover, pre-laid circuit 1020 can be electrically coupled to cascaded string 1018.

Tile spacer 1006 can include a circuit component 1022 embedded inside its body, including both the base section and the wing sections of tile spacer 1006. In some embodiments, circuit component 1022 can include one or more metallic strips. The thickness of the wing section can be between 0.3 and 1 mm (e.g., 0.5 mm), and the thickness of the metallic strips embedded within tile spacer 1006 can be between 0.1 and 0. 5 mm (e.g., 0.3 mm).

Edges of embedded circuit component 1022 can extend beyond the edges of the wings of tile spacer 1006 to come into contact with the pre laid circuits (e.g., pre-laid circuit 1020) within each solar roof tile. As a result, electrical coupling can be established between the cascaded strings within the adjacent solar roof tiles. Depending on the configurations of the pre-laid circuits, in-series or in-parallel coupling between the cascaded strings can be achieved.

In the example shown in FIG. 10, encapsulant layer 1016 is mostly positioned on the front side of cascaded string 1018. Alternatively, an additional encapsulant layer can be placed on the back side of cascaded string 1018. However, in such a scenario, openings need be created on the back side encapsulant layer to facilitate electrical coupling between pre-laid circuit 1020 and cascaded string 1018.

Featured image: Solarroof Cool