A solar cell module is made up with a plurality of solar cells electrically connected in series and/or in parallel with each other with wiring members that are electrically connected to electrodes on surfaces of the solar cells. In solar cell module assembly, connection between the electrodes on the solar cells and wiring members are conventionally made with solder. Solder is widely used because it has excellent electric conductivity and reliable connectivity, i.e., high adherability, and it is an inexpensive material suited for many general-purpose applications.
On the other hand, some wire connecting methods without use of solder are being developed to reduce the influence of heat during the wiring member connection. For example, a well-known method uses a resin adhesive to connect the solar cells and wiring members (see, e.g., PTL 1).
Wire connection with a resin adhesive begins with applying the resin adhesive between electrodes of a solar cell and wiring members and then heating the solar cell and wiring members while relatively applying pressure, thereby connecting the wiring members to the electrodes of the solar cell.
By the way, for the purpose of cost reduction and resource savings associated with solar cells, thinner solar cells are now in increasing demand.
The aforementioned wire connection method with the resin adhesive utilizes relative pressurization to connect the wiring members to the solar cell. The pressure applied for connection is partially transferred to the solar cell through the electrodes, and sometimes, the pressure creates shear stresses on a substrate of the solar cell, the stress being derived from the positional relationship between the electrodes formed on a light-receiving surface and the electrodes formed on a rear surface of the solar cell. The shear stresses cause cracks in the substrate, which lead to yield reduction. It is therefore especially important to deal with the shear stresses in the thinner solar cells.
To solve the above-described problem, the applicant of the present invention has proposed a solar cell module including a plurality of first finger electrodes that are disposed on a light-receiving surface and connected to wiring members and a plurality of second finger electrodes that are disposed on a rear surface and connected to wiring members, wherein the first finger electrodes and second finger electrodes are arranged so as to overlap one another on a projection plane in parallel with the light-receiving surface (see PTL 2).
USPTO Backgrounds
USPTO Backgrounds