System and method of manufacturing high-strength bonded metal sheets for a battery cell are provided. The method comprises providing a stackup comprising a first metal sheet and a second metal sheet. The first and second metal sheets are separated by a first coating layer. The first coating layer comprises nickel-phosphide. The first metal sheet includes a first material of a first melting point and the second metal sheet includes a second material of a second melting point. The first coating layer including a third material of a third melting point. The method further comprises heating the stackup to allow crystallization of nickel in the first coating layer and remove the residual nickel-phosphide defining an enhanced coating layer. The enhanced coating layer comprises crystallized nickel for high-strength solid state bonding of the first and second metal sheets to the enhanced coating layer.

System and method of manufacturing high-strength bonded metal sheets for a battery cell are provided. The method comprises providing a stackup comprising a first metal sheet and a second metal sheet. The first and second metal sheets are separated by a first coating layer. The first coating layer comprises nickel-phosphide. The first metal sheet includes a first material of a first melting point and the second metal sheet includes a second material of a second melting point. The first coating layer including a third material of a third melting point. The method further comprises heating the stackup to allow crystallization of nickel in the first coating layer and remove the residual nickel-phosphide defining an enhanced coating layer. The enhanced coating layer comprises crystallized nickel for high-strength solid state bonding of the first and second metal sheets to the enhanced coating layer.

A current source module for joining methods with current-generated heat support that includes a base body formed monolithically as a single component, having a first immovable attachment element for connecting a first joining tool and at least one formed first receiving space. In the first receiving space, a control element is disposed including a linearly movable second attachment element for connecting to a second joining tool, and in the first or additional receiving space a transformer unit for electrical supply is disposed. Furthermore, a welding gun is provided that includes such current source module, and a first joining tool formed as an immovable electrode arm, and a second joining tool formed as a movable electrode arm, wherein the immovable arm is connected to the first attachment element and the movable arm is connected to the second linearly movable attachment element, wherein the electrode arms include electrodes connected to the transformer.

Provided is a current control method for resistance spot welding in which a plurality of overlapped metal plates are welded together by being sandwiched between a pair of electrodes and energized while applying pressure. The current control method includes sequentially acquiring an electrical resistance between the pair of electrodes during welding; sequentially calculating an expansion amount caused by the welding using a strain calculated from the pressure applied by the electrodes and a stroke of the electrode; sequentially calculating a computational nugget diameter by using the electrical resistance and the expansion amount, the computational nugget diameter being a diameter of a nugget formed during the welding; and sequentially determining a current to be applied between the pair of electrodes during the welding using a difference between the computational nugget diameter and a master computational nugget diameter calculated in master welding in which no gap exists between the metal plates and a nugget with a target diameter is obtained by the welding.

Provided is a current control method for resistance spot welding in which a plurality of overlapped metal plates are welded together by being sandwiched between a pair of electrodes and energized while applying pressure. The current control method includes sequentially acquiring an electrical resistance between the pair of electrodes during welding; sequentially calculating an expansion amount caused by the welding using a strain calculated from the pressure applied by the electrodes and a stroke of the electrode; sequentially calculating a computational nugget diameter by using the electrical resistance and the expansion amount, the computational nugget diameter being a diameter of a nugget formed during the welding; and sequentially determining a current to be applied between the pair of electrodes during the welding using a difference between the computational nugget diameter and a master computational nugget diameter calculated in master welding in which no gap exists between the metal plates and a nugget with a target diameter is obtained by the welding.

The invention relates to an energy supply system for a mobile resistance welding machine for flash-butt welding of track rails, comprising a combustion engine (1) coupled to a generator (2) as well as a charging device (5) for charging an energy store (7), wherein the energy store (7) is a buffer element of an intermediate circuit (13) to which a welding inverter (14) is connected. In this, the energy supply system comprises an island grid to which the generator (2) is connected and which is coupled to the intermediate circuit (13) by a controlled power converter (16).

Provided is a resistance spot welding method. The resistance spot welding method for joining a sheet set including a plurality of lapped steel sheets includes: holding the sheet set between a pair of electrodes; and energizing the sheet set under application of electrode force to thereby join the steel sheets together. At least one of the plurality of lapped steel sheets is a surface-treated steel sheet including a metal coating layer on a surface thereof. The energizing includes: a primary energizing step of performing energization to form a nugget portion; a non-energizing step in which, after the primary energizing step, the energization is suspended for an energization suspension time Tc (cycles); and a secondary energizing step of, after the non-energizing step, performing energization for reheating while the nugget portion is prevented from growing. During the energizing, the relations of a particular formula are satisfied.

Provided is a spot welding method by which welding can be successfully performed while inhibiting occurrence of expulsion. First to third metal plates W1 to W3 were welded in which ratio of total thickness to thickness of the first metal plate W1 is 7. In Example 1, peak current value A1 is 14.6 kA, effective current value A2 is 7.8 kA, peak duration T1 is 0 ms, and no-peak duration T2 is 5.9 ms. As a result, in Example 1, lower limit current value A3 is 6.9 kA, upper limit current value A4 is 8.42 kA, difference A5 between upper limit current value A4 and lower limit current value A3 is 1.52 kA, peak duration T1/no-peak duration T2 is 0, effective current value A2/peak current value A1 is 0.53, and rising time T3/falling time T4 is 0.79, furthermore, no expulsion occurs, and welding result was determined to be OK.

Provided is a spot welding method by which welding can be successfully performed while inhibiting occurrence of expulsion. First to third metal plates W1 to W3 were welded in which ratio of total thickness to thickness of the first metal plate W1 is 7. In Example 1, peak current value A1 is 14.6 kA, effective current value A2 is 7.8 kA, peak duration T1 is 0 ms, and no-peak duration T2 is 5.9 ms. As a result, in Example 1, lower limit current value A3 is 6.9 kA, upper limit current value A4 is 8.42 kA, difference A5 between upper limit current value A4 and lower limit current value A3 is 1.52 kA, peak duration T1/no-peak duration T2 is 0, effective current value A2/peak current value A1 is 0.53, and rising time T3/falling time T4 is 0.79, furthermore, no expulsion occurs, and welding result was determined to be OK.

A multi-tiered weld program that is effective in resistance spot welding of dissimilar materials is disclosed. The process is repeatable across a multitude of grades/thicknesses, and number of sheets of conductive materials, and is possible to perform with traditional weld tooling and electrodes. Different size/different material/different contact face geometries weld surfaces are used to balance thermal properties of the materials, and the process is designed to create a small, consistent Intermetallic Compound (IMC) that is effective in holding two different conductive materials together with a high level of strength that is suitable for industrial mass production. The multi-tiered resistance spot weld process uniformly preheats, welds, and cools the samples to control the formation of the IMC that is formed therein.