The solar array for the solar car including encapsulation and cell selection

Scope of Works and Specifications:

The following outlines the specific tasks and requirements for the provision of the solar array. Please note, to receive further information to provide a quotation a Non Disclosure agreement is required to be signed and returned to the University. 

Western Sydney Solar Team will submit the solar array plans of the design for manufacturing following the completion of a Non disclosure agreement. This will be multiple files of the solar cell module layout that will fit into the recess of the aero body top shell. It will include projections the solar cell module placement and area, wiring and cell direction. Furthermore, additional details inclusive of the quantity of cells, required modules thickness and double curvature radius will be outlined in documentation by the Team. The team will be able to collaborate with the vendor to ensure the files are manufacturable to the outlined requirements.

Supply Photovoltaic Cells 

The vendor will have in supply individual Maxeon/Sunpower Pe monocrystalline silicon unencapsulated cells that are both equal or greater than 25.4% power efficient, resulting in 3.94 to 4.02 watts per cell. These cells are approximately 125mm by 125 mm and will have interdigitated back contacts. A total of 1000 Pe class cells must be supplied from the vendor, with the sponsorship of 600 Pe class cells from an agreement supplied by the vendor in tandem with Maxeon/Sunpower.

Dicing Photovoltaic Cells The vendor will be capable of precisely cutting the selected cells in parallel to the interdigitated back contacts, reducing the width equally relative to the centre of the terminal. This will result in a final individual cell with a width of 82.8 mm and 125 mm in length, with a tolerance of +/- 0.005mm in both directions.

Encapsulation and Modules

The vendor will use a non-reflective structure coating on the surface of the solar cell modules. The thickness of the module in addition to VHB tape will be sized to lay planar into the recess determined by the aero body top shell designed by the Team. The vendor will collaborate with the Team to determine the direction and quantity of each unique modular string, which includes non-symmetrical modules.

The tolerances of will all be within a margin of error of less than +/- 0.2 mm per module with each module designed for:

- Cell-to-cell gap of 0.6 mm

- Cell-to-edge gap of 2 mm

- Module-to-module gap of 1 mm

- Module thickness of 0.7 mm

- A lightweight module weighing approx. 1000 grams per square meter

The vendor will have conductive, solderable flat tabs on the terminal points of each module; and will be supplied with the locations of the where terminals and additional tabs are located by the Team. The terminals must also stick out from the laminated underside of the module, and be able to turn normal to this surface for soldering wired connections.

The vendor will be able to laminate cells into modules up to 7 by 6 cells to the specified dimensions, laminate a minimum of 2 by 1 cells to the specified dimensions; and laminate non symmetrical, non-rectangular cell layouts to dimensions provided by the Team. The lamination material must be semi-flexible while maintaining rigidity to conform to the top shell of the car.

Quality Control

Inclusive of the deliverables above, each module produced must be free from any defects. This includes damaged/cracked photovoltaic cells, delamination of the modules, and all performance damaging blemishes that are preventable during the previously mentioned processes undertaken by the vendor. The total apparent surface of all solar cells must not exceed, nor fall short of specified number of permissible diced cells, equal to 579, for the given conditions above.

This is defined by the regulations set by the Bridgestone World Solar Challenge 2025, and is the maximum number of cells allowable to achieve 6m^2 of active cell area when dimensions are 82.8 mm by 125 mm per cell.