A photovoltaic module, comprising a solar cell string, and the solar cell string comprising: a plurality of solar cells cut from a solar cell substrate along a first direction, wherein a number of the plurality of solar cells is N and N≥2, the plurality of solar cells is arranged in sequence along the first direction, each of the plurality of solar cells comprises a single-layer region and an overlapping region, and adjacent solar cells are stacked in the overlapping region; and a plurality of solder strips each being welded to a front surface of one of the plurality of solar cells and a back surface of another solar cell to connect the two adjacent solar cells together, the plurality of solder strips each comprising a reflective section and a flat section connected to the reflective section, wherein the reflective section is located on the front surface of the solar cell and welded to the single-layer region, the flat section is at least partially located in the overlapping region between the two stacked solar cells, a thickness of the reflective section is within a range of 0.18mm to 0.27mm, and a thickness of the flat section is within a range of 0.08mm to 0.15mm; and wherein the photovoltaic module further comprises two protective adhesive layers respectively covering a front surface and a back surface of the solar cell string; a transparent plate covering a surface of the protective adhesive layer on the front surface of the solar cell string; and a back plate covering a surface of the protective adhesive layer on the back surface of the solar cell string; wherein a size difference between a thickness of one protective adhesive layers and a thickness of the reflective section of the solder strip is defined as a first thickness, a ratio of the first thickness to the thickness of one protective adhesive layer is not less than 5% and not greater than 15%. a plurality of solar cells cut from a solar cell substrate along a first direction, wherein a number of the plurality of solar cells is N and N≥2, the plurality of solar cells is arranged in sequence along the first direction, each of the plurality of solar cells comprises a single-layer region and an overlapping region, and adjacent solar cells are stacked in the overlapping region; and a plurality of solder strips each being welded to a front surface of one of the plurality of solar cells and a back surface of another solar cell to connect the two adjacent solar cells together, the plurality of solder strips each comprising a reflective section and a flat section connected to the reflective section, wherein the reflective section is located on the front surface of the solar cell and welded to the single-layer region, the flat section is at least partially located in the overlapping region between the two stacked solar cells, a thickness of the reflective section is within a range of 0.18mm to 0.27mm, and a thickness of the flat section is within a range of 0.08mm to 0.15mm; and wherein the photovoltaic module further comprises two protective adhesive layers respectively covering a front surface and a back surface of the solar cell string; a transparent plate covering a surface of the protective adhesive layer on the front surface of the solar cell string; and a back plate covering a surface of the protective adhesive layer on the back surface of the solar cell string; wherein a size difference between a thickness of one protective adhesive layers and a thickness of the reflective section of the solder strip is defined as a first thickness, a ratio of the first thickness to the thickness of one protective adhesive layer is not less than 5% and not greater than 15%.