Method and apparatus for pressure welding stacked metal foils

Claim 3

The method recited in claim 1, wherein, with horizontal operation of the welding electrodes, the foil stack is clamped only near the ends to be welded between the holding jaws.

Claim 4

Apparatus for the local joining of stacked metal foils in strip form by electrical pressure welding at both ends of the foil stack, comprising welding electrodes for conducting a welding current through the region of the foil stack to be joined and wherein a means for heat removal from the foil stack is provided, the apparatus further comprising: means for receiving a prepared stack of foils between holding jaws with ends of the foil stack overhanging on both sides; means for transferring the holding jaws from a ready position provided near the welding electrodes into an operating position in which one end of the foil stack protrudes between the welding electrodes and for transferring the holding jaws from the operating position back into the ready position after welding; means for applying the welding electrodes to the one end of the foil stack for conducting a welding current through the stack of foils and for exposing the holding jaws to a coolant; means for turning off the welding current and for disengaging the welding electrodes; and means for tilting the holding jaws for positioning the other end of the foil stack for pressure welding of the other end; and further wherein: said holding jaws comprises two holding jaws which are arranged movably relative to each other comprising highly heat-conducting material which have at least one canal each for conducting a coolant therethrough; the holding jaws having clamping surfaces which are formed so as to interleave, with a curvature in the same direction and forming a substitute form for the shape of the finished, welded foil stack when in use.

Claim 5

Apparatus for the local joining of stacked metal foils in strip form by electrical pressure welding at both ends of the foil stack, comprising welding electrodes for conducting a welding current through the region of the foil stack to be joined and wherein a means for heat removal from the foil stack is provided, the apparatus further comprising: means for receiving a prepared stack of foils between holding jaws with ends of the foil stack overhanging on both sides; means for transferring the holding jaws from a ready position provided near the welding electrodes into an operating position in which one end of the foil stack protrudes between the welding electrodes and for transferring the holding jaws from the operating position back into the ready position after welding; means for applying the welding electrodes to the one end of the foil stack for conducting a welding current through the stack of foils and for exposing the holding jaws to a coolant; means for turning off the welding current and for disengaging the welding electrodes; and means for tilting the holding jaws for positioning the other end of the foil stack for pressure welding of the other end; and further wherein: said holding jaws comprises two holding jaws which are arranged movably relative to each other comprising highly heat-conducting material which have at least one canal each for conducting a coolant therethrough; the holding jaws having clamping surfaces which are formed so as to interleave, with a curvature in the same direction and forming a substitute form for the shape of the finished, welded foil stack when in use.

Claim 6

The apparatus recited in claim 3, wherein at least one of the two cooperating holding jaws is designed divided and the sections thereof can be moved by separate driving means.

Claim 7

The apparatus recited in claim 3, wherein an inner outwardly curved holding jaw and two outer holding jaws which bias the foil stack against the inner holding jaw are provided which cover only the region of the foil stack adjoining the end of the foil stack, and the outer holding jaws can be moved successively such that initially, the first outer holding jaw can be placed against the foil stack; the second outer holding jaw can be moved against the foil stack and subsequently, the first outer holding jaw can be removed.

Claim 10

Apparatus for the local joining of stacked metal foils in strip form by electrical pressure welding at both ends of the foil stack, with welding electrodes for conducting a welding current through the region of the foil stack to be joined and wherein a means for heat removal from the foil stack is provided, the apparatus further method comprising: means for receiving a prepared stack of foils between holding jaws with ends of the foil stack overhanging on both sides; means for transferring the holding jaws from a ready position provided near the welding electrodes into an operating position in which one end of the foil stack protrudes between the welding electrodes and for transferring the holding jaws from the operating position into the ready position after welding; means for applying the welding electrodes to the one end of the foil stack, for conducting a welding current through the stack of foils and for exposing the holding jaws to a coolant; means for turning off the welding current and for disengaging the welding electrodes; and means for tilting the holding jaws for positioning the other end of the foil stack for pressure welding of the other end; and further comprising: a switching device which can be controlled as a function of the temperature of the welding spot for influencing the welding current, the switching device being associated with an infrared detector for obtaining a temperature-dependent control signal.

Claim 11

Apparatus for the local joining of stacked metal foils in strip form by electrical pressure welding at both ends of the foil stack, with welding electrodes for conducting a welding current through the region of the foil stack to be joined and wherein a means for heat removal from the foil stack is provided, the apparatus further method comprising: means for receiving a prepared stack of foils between holding jaws with ends of the foil stack overhanging on both sides; means for transferring the holding jaws from a ready position provided near the welding electrodes into an operating position in which one end of the foil stack protrudes between the welding electrodes and for transferring the holding jaws from the operating position into the ready position after welding; means for applying the welding electrodes to the one end of the foil stack, for conducting a welding current through the stack of foils and for exposing the holding jaws to a coolant; means for turning off the welding current and for disengaging the welding electrodes; and means for tilting the holding jaws for positioning the other end of the foil stack for pressure welding of the other end; and further comprising: a switching device which can be controlled as a function of the temperature of the welding spot for influencing the welding current, the switching device being associated with an infrared detector for obtaining a temperature-dependent control signal.

Claim 12

The apparatus recited in claim 7, wherein two infrared detectors are provided, of which one points to the end face of the free end of the foil stack and a second points to the region of the foil stack near the holding jaws, the switching device having two switching stages operative as a function of the temperature at the free end of the foil stack and being a function of the temperature near the holding jaws, of which the first causes a reduction of the welding current and the second, the interruption of the welding current.

Claim 13

The apparatus recited in claim 7, wherein two infrared detectors are provided which point to the corner regions on the end face of the end of the foil stack to be accepted between the welding electrodes.