The present technology relates to a method for evaluating resistance welding quality of a battery by using eddy current signal characteristics, wherein high reliability can be provided by preventing an error caused by a variation according to differences in physical properties of individual batteries, and an evaluation process is simple and clear by applying a non-destructive method.

A method of resistive joining of metal sheets for a battery cell is provided. The method comprises providing an asymmetrical stackup comprising a first set of first metal sheets and a second set of second metal sheets. The first metal sheets arranged in sequence relative the second metal sheets defining the asymmetrical stackup. Each of the first and second metal sheets separated by a coating layer. The first metal sheets include a first material of a first melting point and the second metal sheets include a second material of a second melting point. The coating layer includes a third material of a third melting point. The first melting point is greater than the second melting point. The third melting point is greater than the second melting point and less than the first melting point. The method further comprises heating the first metal sheets to a first temperature to allow solid state bonding of the first metal sheets and to allow solid state bonding of the first set to the second set. The method further comprises heating the second metal sheets to a second temperature to allow fusion bonding of the second metal sheets.

A bonding probe is used for bonding a cover sheet to a core to form or repair a dual wall structure. The bonding probe includes a body, an attachment end at a distal end of the body, a head at an opposite end of the body, a tip extending from the head, and a cooling passageway. The attachment end couples the body to a resistance welder. The tip extends to form a proximate end of the body. The tip includes a contacting area having a predetermined three dimensional contoured surface. The contacting area aligns with a predetermined area of a three dimensional outer surface of a cover sheet of a dual walled structure. The cooling passageway provides a passageway for a flow of cooling fluid. The cooling passageway extends through the head, and into the tip.

A welded assembly includes a first object or substrate, an interlayer, and a subsequent layer deposited on the interlayer. The interlayer is an ESD coating deposited on the first object, and the subsequent layer is deposited by ESD on the interlayer. The subsequent layer is made of a different materials from the substrate. Both the interlayer and the subsequent layer are subject to peening. In one case the interlayer has a lower either a lower thermal conductivity or a lower electrical conductivity than the substrate and the subsequent layer. In another example, the subsequent layer has a cermet content of greater than 40% by wt.

A workpiece of Ti or a Ti alloy includes a surface with a coating layer of titanium nitride. A region of the surface includes a connection zone of a Ti—N solid solution alloy. A second Ti or Ti alloy workpiece is contacted with the connection zone, and a weld joint is formed across the connection zone with a resistance welding process. The weld joint extends into the first Ti workpiece and the second Ti workpiece.

A system is for bonding a cover sheet to a core to form or repair a dual wall structure. The system includes a cover sheet probe and an inner pedestal probe. A three dimensional contoured tip of the cover sheet probe abuts against a three dimensional contoured outer surface of the cover sheet opposite a pedestal of the core. The pedestal abuts the inner surface of the cover sheet. The inner pedestal probe may be coupled to the core to create a conductive electrical path from the cover sheet probe through at least part of the structure. A flow of electric power is controlled and supplied to the cover sheet probe to heat a junction between the area of the cover sheet abutting the pedestal and the pedestal. A heated area is created in the junction and fixedly couples the coversheet and the pedestal.

Methods for resistance welding, resistance-welded assemblies, and vehicles including resistance-welded assemblies are provided. The method includes providing a workpiece stack-up including first and second workpieces and an intermediate material located between the faying surfaces thereof. At least one of the first workpiece and the second workpiece is formed of a first metal alloy with a first concentration of an alloying element, and the intermediate material is formed of a second metal alloy of the first metal and a second concentration of the alloying element that is less than the first concentration. The method includes bringing electrodes into contact with the workpieces, passing an electrical current therebetween to form a molten weld pool, and cooling the molten weld pool into a weld nugget that forms all or part of a weld joint between the workpieces and has a composition that is a mixture of the workpieces and the intermediate material.

The invention relates to a welding electrode for resistance welding, formed by a welding tool made of a metal, the welding tool having a contact surface that comes into contact with the workpiece to be welded. In order to avoid adhesion between the contact surface and a workpiece made, in particular of aluminum, it is suggested in the invention that the contact surface is made of diamond doped with boron.

A method for producing a secondary battery according to the present invention comprises a step wherein a negative electrode collector, which has a projection having a height of from 0.36 mm to 0.45 mm on at least one of a first member and a second member, said members constituting the negative electrode collector, is resistance-welded with a core multilayer part in such a manner that the core multilayer part is sandwiched between the first member and the second member, while having the projection in contact with the core multilayer part.

A bonding system is used for bonding a cover sheet to a core to form or repair a dual wall structure. The bonding system includes a plurality of bonding probes and controller circuitry. The bonding probes include a three dimensional (3D) contoured tip configured to align with a predetermined area of a 3D contoured cover sheet of a dual wall structure. The controller circuitry comprises processor circuitry and sensor circuitry. The sensor circuitry provides a location of an area of the 3D contoured cover sheet for bonding. The processor circuitry identifies a bonding probe having a contacting area that aligns with the 3D contour of the cover sheet in the location provided by the sensor circuitry.