A method of welding two pieces of metal together, the method comprising: associating a first piece of metal with a second piece of metal; directing a laser beam toward the first and second pieces of metal; wherein the laser beam initially contacts the first piece of metal and penetrates to the second piece of metal; wherein the laser beam has a wavelength in the range of about 400 nm to about 500 nm; wherein the pieces of metal absorb from about 40% to about 75% of the laser beam; wherein the first piece is a foil having a thickness of from about 5 μ m to about 100 μ m; and, whereby the pieces are welding together; wherein the first piece of material comprises: - a metal selected from the group consisting of copper, copper alloys, gold, gold alloys, stainless steel and aluminium alloy; and wherein the second piece of metal: - comprises either aluminum or copper when the first material comprises aluminium alloy; or - is selected from the group of consisting of materials electroplated with gold, materials electroplated with platinum, and materials electroplated with copper, or - is selected from the group consisting of an aluminum buss bar, an aluminum alloy buss bar, a copper tab, a copper alloy tab, a nickel plated copper buss bar, a nickel plated copper alloy buss bar, a nickel plated aluminum bus bar, and a nickel plated aluminum alloy buss bar, or - is selected from the group consisting of nickel plated materials, nickel plated copper, nickel plated aluminum, nickel plated copper alloys, nickel plated aluminum alloys, and stainless steel. associating a first piece of metal with a second piece of metal; directing a laser beam toward the first and second pieces of metal; wherein the laser beam initially contacts the first piece of metal and penetrates to the second piece of metal; wherein the laser beam has a wavelength in the range of about 400 nm to about 500 nm; wherein the pieces of metal absorb from about 40% to about 75% of the laser beam; wherein the first piece is a foil having a thickness of from about 5 μ m to about 100 μ m; and, whereby the pieces are welding together; wherein the first piece of material comprises: - a metal selected from the group consisting of copper, copper alloys, gold, gold alloys, stainless steel and aluminium alloy; and wherein the second piece of metal: - comprises either aluminum or copper when the first material comprises aluminium alloy; or - is selected from the group of consisting of materials electroplated with gold, materials electroplated with platinum, and materials electroplated with copper, or - is selected from the group consisting of an aluminum buss bar, an aluminum alloy buss bar, a copper tab, a copper alloy tab, a nickel plated copper buss bar, a nickel plated copper alloy buss bar, a nickel plated aluminum bus bar, and a nickel plated aluminum alloy buss bar, or - is selected from the group consisting of nickel plated materials, nickel plated copper, nickel plated aluminum, nickel plated copper alloys, nickel plated aluminum alloys, and stainless steel. - a metal selected from the group consisting of copper, copper alloys, gold, gold alloys, stainless steel and aluminium alloy; and wherein the second piece of metal: - comprises either aluminum or copper when the first material comprises aluminium alloy; or - is selected from the group of consisting of materials electroplated with gold, materials electroplated with platinum, and materials electroplated with copper, or - is selected from the group consisting of an aluminum buss bar, an aluminum alloy buss bar, a copper tab, a copper alloy tab, a nickel plated copper buss bar, a nickel plated copper alloy buss bar, a nickel plated aluminum bus bar, and a nickel plated aluminum alloy buss bar, or - is selected from the group consisting of nickel plated materials, nickel plated copper, nickel plated aluminum, nickel plated copper alloys, nickel plated aluminum alloys, and stainless steel. - is selected from the group of consisting of materials electroplated with gold, materials electroplated with platinum, and materials electroplated with copper, or - is selected from the group consisting of an aluminum buss bar, an aluminum alloy buss bar, a copper tab, a copper alloy tab, a nickel plated copper buss bar, a nickel plated copper alloy buss bar, a nickel plated aluminum bus bar, and a nickel plated aluminum alloy buss bar, or - is selected from the group consisting of nickel plated materials, nickel plated copper, nickel plated aluminum, nickel plated copper alloys, nickel plated aluminum alloys, and stainless steel.