Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/06—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating by means of high energy impulses, e.g. magnetic energy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/002—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating specially adapted for particular articles or work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/02—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating by means of a press ; Diffusion bonding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/22—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/04—Construction or manufacture in general
  • H01M10/0404—Machines for assembling batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/058—Construction or manufacture
  • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/50—Current conducting connections for cells or batteries
  • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
  • H01M50/514—Methods for interconnecting adjacent batteries or cells
  • H01M50/516—Methods for interconnecting adjacent batteries or cells by welding, soldering or brazing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/50—Current conducting connections for cells or batteries
  • H01M50/543—Terminals
  • H01M50/547—Terminals characterised by the disposition of the terminals on the cells
  • H01M50/55—Terminals characterised by the disposition of the terminals on the cells on the same side of the cell
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2101/00—Articles made by soldering, welding or cutting
  • B23K2101/36—Electric or electronic devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2101/00—Articles made by soldering, welding or cutting
  • B23K2101/36—Electric or electronic devices
  • B23K2101/38—Conductors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/08—Non-ferrous metals or alloys
  • B23K2103/10—Aluminium or alloys thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/08—Non-ferrous metals or alloys
  • B23K2103/12—Copper or alloys thereof

Definitions

• the present invention relates to a welding method and to a welding device for welding to one another a plurality of layers of metal material at least partially overlapped.
• the present invention is advantageously, but not exclusively, applied to the production of a power storage device, to which the following description will explicitly refer without thereby losing generality. Even more in particular, the present invention is advantageously, but not exclusively, applied to welding a plurality of layers of electrode tabs to one another and/or at least one electrode tab layer to at least one terminal metal layer and/or a support structure of a power storage device.
• heat welding systems without filler materials are mainly widespread, such as for example ultrasonic welding systems, where the heat is generated by the friction caused by the vibration with ultrasonic frequency of at least one of the elements to be welded, or laser welding, where the heat is generated by the huge energy provided by the laser beam and concentrated at a given focus.
• the welding of the terminal electrode tabs of the electrode layers to one another and/or to possible terminal metal elements (having greater thickness) and/or to a support structure, made of metal as well typically occurs by means of ultrasonic or laser welding systems.
• the known ultrasonic welding systems entail disposing the layers of metal material to be welded between an anvil and a sound wave emitter (also known as sonotrode) connected to a piezoelectric transducer, or to a converter, designed to convert an electronic ultrasound signal into a vibration which is then transferred (precisely by means of the sonotrode) to the zone to be welded.
• the energy created by the sound waves melts the layers of metal material to be welded, allowing the founding and thus the welding to one another of the layers of metal material.
• Laser welding instead, entails the use of a welding device configured to emit and focus, by means of one or more lenses or mirror galvanometers, a laser beam on the plurality of layers of metal materials to be treated. The intensity, the speed of movement and the frequency of the emitted laser beam varies upon the varying of the material and/or of the thickness and/or of the layers to be treated.
• the maintenance of the abovementioned welding devices is particularly onerous, since the sonotrode has to be frequently replaced due to the great wear and, at each modification, the abovementioned complex setting operations have to be repeated.
• One of the objects of the present invention is to provide an alternative welding method and device for welding to one another a plurality of layers of metal material at least partially overlapped, which at least partly overcome the abovementioned drawbacks ensuring, at the same time, a welding quality and reliability that stands comparison with the welding quality and reliability of the known welding systems.
• an assembling method and an assembling apparatus for assembling a power storage device are provided according to what is claimed in the appended independent claims, and preferably, in any one of the claims directly or indirectly dependent on the independent claims.
• FIG. 1 and 2 schematically illustrate views in lateral section of a welding device, according to a first embodiment of the invention, in two different operating configurations, with several parts removed for clarity;
• FIG. 3 and 4 schematically illustrate views in lateral section of a welding device according to a second embodiment of the invention in two different operating configurations
• FIG. 3a and 4a schematically illustrate views in lateral section of a welding device according to a third embodiment of the invention in two different operating configurations
• FIGs 9, 10 and 11 schematically illustrate perspective views and on an enlarged scale of three different variants of the welding element 5 of the welding device of Figures 1 and 2, or of Figures 3 and 4, or of Figures 3a and 4a;
• Figures 12 and 13 illustrate a schematic representation of subsequent steps of a welding method performed in accordance with the present invention
• FIG. 14 is an enlarged view of a part of Figure 13;
• FIG. 15 and 16 illustrate two power storage devices wherein welds made by a device or by the method in accordance with the present invention are visible;
• Figure 17 schematically illustrates an apparatus comprising a device in accordance with the present invention and configured to perform the method in accordance with the present invention.
• reference numeral 1 indicates, as a whole, a welding device for welding to one another a plurality of layers 2 ( Figures 12-17) of metal material at least partially overlapped.
• the welding device 1 is configured to weld together from 2 up to approximately 80 layers of metal material (preferably 2, or from 20 to 60, more precisely 40).
• the welding device 1 is configured to weld to one another a plurality of layers 2 of metal material at least partially overlapped.
• At least one of the overlapped layers 2 of metal material to be welded has a configuration at least partially planar and has a (total) thickness ranging from approximately 5 pm to approximately 600 pm, even more in particular from approximately 50 pm to approximately 300 pm, more precisely from approximately 100 pm to approximately 200 pm.
• the reduced thickness ensures, in fact, a high deformation of the layer 2 of metal material, facilitating the welding thereof, as will be described below.
• such layers 2 of metal material can each be made of aluminum, or copper, or gold, or brass or any combination or alloy thereof.
• At least one of the layers 2 of metal material to be welded to one another is an electrode tab B.
• the various layers 2 of the plurality of layers 2 of metal material to be welded can be made of different materials, for example one of the layers can be an electrode tab, whereas the other one can be a different metal element, for example a metal plate.
• At least one of the layers 2 of metal material to be welded is an electrode tab B ( Figures 15 and 16), i.e. the portion of electrode (generally copper for the cathode and aluminum or zinc for the anode) protruding from a stack so as to electrically interconnect to one another several layers of a same electrode (positive or negative).
• the welding device 1 comprises a support portion 4 and a welding element 5, in particular a rod, which is coupled in a sliding (and removable) manner to the support portion 4 and has, at one end 6 thereof, at least one welding tip 7 designed to exert a welding action upon the plurality of layers 2 of metal material to be welded.
• the welding element 5 is movable relative to the support portion 4 between at least a first position in a rest configuration I (see Figures 1 and 3) and a second position in an operating configuration 0 (see Figures 2, 4 and 4a).
• the welding element 5 is disposed so as to be in contact with the layers 2 of metal material to be welded.
• the welding element 5 is disposed so as to lightly press (i.e. substantially without deforming them) the layers 2 of metal material.
• the welding element 5 is disposed so as to at least partially penetrate the volume initially occupied by the layers 2 of metal material to be welded.
• the welding device 1 further comprises pushing means 8, which cooperate with the welding element 5 and can be operated, preferably by means of the application of a force from the outside, so as to transfer an impulsive force F onto the welding element 5 so as to cause the welding element 5 to move from the first position to the second position (i.e. from the configuration I to the configuration 0).
• pushing means 8 which cooperate with the welding element 5 and can be operated, preferably by means of the application of a force from the outside, so as to transfer an impulsive force F onto the welding element 5 so as to cause the welding element 5 to move from the first position to the second position (i.e. from the configuration I to the configuration 0).
• the expression "impulsive force” means a force that acts with a high module for a very short lapse of time, for example in the order of hundredths of a second, even more preferably of thousandths of a second.
• the impulsive force acts for a lapse of time ranging from 0.1ms to 200ms (in particular from 0.2 to 100 milliseconds, more in particular from 0.2 to 80 milliseconds).
• the impulsive force F ranges from approximately 500 N to approximately 1400 N, in particular from approximately 650 N to approximately 800 N.
• the impulsive force is generated by means of an impact between two elements of the welding device 1.
• the welding device 1 is configured so that, while shifting from the rest configuration I to the operating configuration 0, the welding tip 7 exerts a welding action upon the plurality of layers 2 of metal material 2 at least partially overlapped such to weld together the layers 2 of metal material 1.
• the layers 2 of metal material are (deeply) plastically deformed in a very short lapse of time; this operation, surprisingly, allows at least partially destroying (or at least generating cracks in) the thin layer of oxide generally present on the outside of the metal surfaces making the distance between the layers 2 of metal material similar to the parameters of the metal lattice of the element by which they are mainly formed, thus facilitating the creation of a strong bond.
• the impulsiveness of the welding force allows preventing the new forming of oxide on the deformed layers 2 of metal material, giving rise to the weld.
• the welding action is a function of the impulsive force F; even more advantageously, welding action means the impact force that the welding tip 7, once subjected to the above-described impulsive force F (transferred by the pushing means 8), exerts upon the plurality of layers 2 of metal material.
• the welding device 1 comprises at least one welding tip 7, advantageously at least two welding tips 7, so as to exert, in use, such welding action upon the plurality of layers 2 of metal material.
• the welding device 1 (in particular the welding element 5) comprises at least four welding tips 7 disposed, for example, on two rows (as illustrated in Figures from 9 to 11), even more preferably six welding tips 7.
• each (or the) welding tip 7 has a polygonal cross section, for example square, or hexagonal.
• each (or the) welding tip 7 has a closed curved section (a simple non-polygon section), for example circular or elliptical .
• each (or the) welding tip 7 extends from the end 6 of the welding element 5 and has, on the opposite side relative to the welding element 5, a flat contact surface 9, which is designed to exert the welding action upon the plurality of layers 2 of metal material at least partially overlapped.
• the flat contact surface is disposed so as to be parallel to the plurality of layers 2 of metal material. More in particular, the flat contact surface is disposed so as to be perpendicular to the direction of the impulsive force F.
• the welding action is exerted upon the overlapping zone, where the layers 2 overlap.
• the flat contact surface 9 has an extension ranging from approximately 0.2 mm 2 to approximately 5 mm 2 (preferably between 0.4 mm 2 and 3 mm 2 ).
• the welding action (pressure) transmitted to the plurality of layers 2 of metal material varies (in particular decreases) in the area of a contact zone 10 ( Figures 12 and 13) between the flat contact surface 9 of the (or of each) welding tip 7 and an outer surface of the overlapped plurality of layers 2 of metal material.
• the welding action (pressure) acting upon the above-described contact zone 10 so as to ensure a correct (plastic) deformation of the various layers 2 of metal material, which will tend to press together and penetrate one another welding to one another (see in particular Figures 13 and 14).
• the welding action (pressure) is controlled by varying the welding element 5, more precisely, by varying the number, the shape and the size of the flat contact surface 9 of the welding tips 7.
• the (or each) welding tip 7 has a trapezoidal (isosceles) cross section, delimited by a major base, in the area of the end 6, and by a minor base, in the area of the contact surface 9.
• the major base and the minor base are connected to one another by means of oblique sides, preferably alike. Between the oblique sides and the minor base, a welding angle is defined.
• the welding angle has a width comprised between 95° and 175° (included).
• the welding angle has a width comprised between 110° and 160° (included). More in particular, the welding angle has a width comprised between 120° and 140° (included).
• the minor base has a length greater than 2/3 of the major base. In other non-limiting cases, the minor base has a length smaller than 2/3 of the major base, in particular smaller than half of the major base, more precisely smaller than one third of the major base.
• the (each) welding tip 7, perimetrically to the contact surface 9, comprises a corner E.
• the contact surface 9 is delimited by the corner E.
• the corner E is a sharp corner, i.e. an edge of rigid material with a radius of curvature (i.e. of beveling) less than 2.5 mm. More precisely, the radius beveling of the corner E is less than 1 mm, specifically less than 0.5 mm, preferably less than 0.2 mm or better 0.1 mm.
• the welding device 1 comprises, more specifically the pushing means 8 of the welding device 1 comprise (in particular are composed of), a spring snapping mechanism 11 which can be operated, advantageously but not limitedly, from the outside, to exert the abovementioned impulsive force F upon the welding element 5.
• the support portion 4 comprises a seat 12 (specifically a recess) suitably dimensioned for receiving the spring snapping mechanism 11, and the spring snapping mechanism 11 is disposed in such seat 12 and is operatively connected to the welding element 5 so as to transmit, once activated, the above-described impulsive force F to such welding element 5.
• the welding device 1, illustrated in Figures 1 and 2 further comprises a sleeve 13 which can slide moving closer or farther to the seat 12, along a direction parallel to a longitudinal axis X of the welding device 1, and is configured to operate the spring snapping mechanism 11, when moved (manually or automatically) closer to the seat 12.
• the welding device 1 also comprises a spring 14 having a given pre-load stretch, advantageously adjustable.
• a spring 14 is operatively connected to the sleeve 13 so as to counter the sliding of the sleeve 13 moving closer to the seat 12.
• such spring 14 is disposed inside the sleeve 13 so that the actuation of the spring snapping mechanism 11 is possible only overcoming the elastic action exerted upon the sleeve 13 by the spring 14.
• the spring snapping mechanism 11 comprises: a triggering element 15 provided, at one end 16 thereof, with an abutment portion 17, and a further spring 18 which has a given pre-load stretch, advantageously adjustable and preferably less than the stretch of the spring 14, and is interposed in contact between the sliding sleeve 13 and the abutment portion 17 so that the sliding of the sleeve 13 towards the seat 12 causes the compression of the spring 18 and a consequent rotation of the triggering element 15, which, when at rest, is in a tilted position relative to a longitudinal axis X of the welding device 1.
• the triggering element 15 moves from an initial position tilted relative to the longitudinal axis X of the welding device 1 (see Figure 1) to a final position in which it is aligned with the longitudinal axis X of the device 1 (see Figure 2).
• the triggering element 15, and in particular the abutment portion 17 of the triggering element 15, abuts against an end 19 of the welding element 5 (in particular opposite the end 6), when the spring 18 is compressed and the triggering element 15 is rotated, so as to be able to transfer onto said welding element 5 the impulsive force (impressed on said coupling element).
• the spring 18 is configured to align, during its compression, the triggering element 15 with the longitudinal axis X of the welding device 1.
• the spring 18 has a countersunk shape along the longitudinal axis X. More in particular, the spring 18 gets narrower while proceeding along the longitudinal axis X towards the welding element 5.
• the triggering element 15 (illustrated in Figures 1 and 2) comprises a main body 20 from which the abutment portion 17 protrudes.
• the main body 20 In the initial tilted position (illustrated in Figure 1) the triggering element 15 is disposed tilted relative to the longitudinal axis X, the main body 20 is surrounded by the spring 18, which (spring 18) at least partially meets the abutment portion 17, so that the compression of the spring 18 determines the transfer of a thrust (generated by the spring 18) onto the abutment portion 17 such to cause the rotation of the triggering element 15 (clockwise, in Figure 1).
• the compression of the spring 18 determines the centering of the triggering element 15 relative to the spring 18 and the alignment of the triggering element 15 with the welding element 5.
• the welding device 1 comprises an impact element 30 (illustrated in Figures 1, 2, 3a and 4a), which is configured to impress the impulsive force F on the welding element 5, in particular on the welding tip 7.
• the sliding sleeve 13 internally has the impact element 30 which is operatively connected to the first spring 14, is configured to impress the impulsive force F (in particular, generated by the movement of the sleeve 13, once overcome the elastic action exerted by the spring 14 by means of the spring snapping mechanism 11) on the spring snapping mechanism 11, in particular on the welding element 5, and comprises a housing 21 which, advantageously but not limitedly, develops parallel to, in particular along, the longitudinal axis X, and is designed to receive a terminal section 31 of the triggering element 15, in particular a terminal section 31 of the main body 20 of the triggering element 15, when the spring 18 is compressed and the abutment portion 17 is in abutment against the end 19 of the triggering element 5.
• the housing 21 acts as guide for the triggering element 15 defining, at the same time, an end-of- stroke for the sliding when moving closer towards the seat 12 of the sliding sleeve 13.
• the above-described impulsive force F is a function of the given pre-load stretch of the springs 14 and/or 18, therefore upon the varying of such pre-load stretch, the impulsive force transferred onto the welding element 5 varies and thus the welding action varies.
• the impact element 30 comprises (at least) a stepped portion 32, which allows (as soon as the triggering element 15, rotating, overpasses the step) impulsively releasing the elastic energy generated by the compression of the springs 14 and/or 18 and impressing the impulsive force F towards the welding element 5, i.e. on the tip 7.
• the impact element 30 springs towards the welding element 5 impressing thereon the impulsive force F.
• the springs 14 and 18 further act as return means 22 cooperating with the welding device 1, exerting a return action upon the welding element 5 so as to cause the shifting from the second position to the first position (i.e. from the operating configuration 0 to the rest configuration I), for example once completed the welding.
• the pushing means 8 coincide with the return means 22.
• the welding device 1 comprises return means 22 (not coinciding with the pushing means 8) suitably configured (only) to exert a return action upon the welding element 5 so as to cause the shifting from the second position to the first position (i.e. from the operating configuration 0 to the rest configuration I).
• the action exerted by the return means 22 is opposite relative to the (to the direction of the) impulsive force F which causes the moving of the welding element 5 from the first position to the second position (i.e. from the configuration I to the configuration 0).
• the welding device 1, in particular the support portion 4, has a substantially cylindrical shape.
• the welding element 5, the housing 21 and, in the final position (configuration 0) also the triggering element 15, are disposed in central position and are coaxial to the support portion 4, i.e. they extend along and symmetrically relative to the longitudinal axis X of the welding device 1.
• the welding device 1 comprises external pushing means, for example an actuator 24 configured to exert the above-described impulsive force upon the welding element 5.
• the actuator 24 is configured to move at least one between the welding element 5 and a different impact element 30 (for example a plate or the support element 4), so as to impress the impulsive force F on the welding element 5 and thus on the tip 7 and make the weld.
• a different impact element 30 for example a plate or the support element 4
• the actuator 24 is operatively coupled (electrically or hydraulically) to an impact element 30 (Figures 3a and 4a) or to the welding element 5 ( Figures 3 and 4), so as to exert the above-described impulsive force upon the welding element 5.
• the actuator 24 is configured to move the impact element 30 ( Figures 3a and 4a) or directly the welding element 5 ( Figures 3 and 4), so as to exert the above- described impulsive force upon the welding element 5 and thus upon the welding tip 7.
• the pushing means 8 of the welding device 1 comprise a hydraulic or electrohydraulic actuator 24, controlled by a control unit 28, for example a (monostable or bistable) solenoid valve, which controls the inlet and/or the outlet of a hydraulic fluid inside, for example, a cylinder.
• a control unit 28 for example a (monostable or bistable) solenoid valve, which controls the inlet and/or the outlet of a hydraulic fluid inside, for example, a cylinder.
• the pushing means 8 of the welding device 1 comprise an electric actuator 24, commanded by a control unit 28, for example a motion controller or an industrial PC, which controls an electric motor 23, in particular a brushless motor.
• a force control so as to be able to vary, based on the format (thickness and number) of the layers 2 of metal material to be welded, the impulsive force F.
• a position control could be carried out so as to vary the first and the second positions based on the format (thickness and number) of the layers 2 of metal material to be welded.
• the welding element 5 and the impact element 30 are configured to slide inside a guide 33, in particular substantially parallel to the longitudinal axis X. More precisely, the motor 23 commands the descent of the impact element 30, which hits the welding element 5, impressing thereon the impulsive force F.
• the (electric) actuator 24 can be operated for moving the welding element 5 or, alternatively, the support portion 4, or a different impact element 30, so as to impact the welding element 5, along a direction parallel to the longitudinal axis X of the welding device 1 and move it between the above-described first and second positions in such a time to allow the application of an impulsive welding action on the layers 2 of metal material.
• the (external) pushing means 8 formed in such manner allow a reduction in the bulks of the welding device 1 (with respect to the embodiment that provides for the spring snapping mechanism 11) and allow adjusting with greater easiness and flexibility the intensity of the impulsive force F, and thus of the welding action to be exerted upon the layers 2 of metal material to be welded.
• the actuator 24 can also be operated to exert the return action, therefore the return means 22 coincide with the pushing means 8 and comprise such (in particular, are composed of such) actuator 24.
• the welding device 1 comprises the support portion 4 and the welding element 5 (of the type described above) coupled in a sliding (and removable) manner to the support portion 4 and having, at one end 6 thereof, at least one welding tip 7, preferably a plurality of welding tips 7, (advantageously of the type described above) for exerting a welding action on the plurality of layers 2 of metal material to be welded.
• the welding device 1 in particular the support portion 4, has a substantially cylindrical shape and the welding element 5 is disposed in central position relative to the support portion 4 and is coaxial to the support portion 4, i.e. it extends along and symmetrically relative to the longitudinal axis X of the welding device 1.
• the pushing means 8 comprise an air piston which can be operated for inducing the shifting of the welding element 5 from the first position to the second position in such a time to allow the application of an impulsive welding action on the layers 2 of metal material to be welded.
• the air piston can also be operated for exerting the return action, therefore the return means 22 coincide with the pushing means 8 and comprise the (in particular, are composed of the) abovementioned hydraulic piston.
• the welding device 1 comprises a contrast element 102, advantageously an anvil, configured to receive the plurality of layers 2 of metal material to be welded and counter the impulsive force F.
• the contrast element 102 is fixed relative to an inertial system.
• contrast element 102 is movable and is configured to perform a movement that opposes the movement of the welding element 5.
• contrast element 102 is made of the same material of the (or of each) welding tip 7.
• contrast element 102 is made of a different material with respect to the (or to each) welding tip 7.
• the contrast element 102 has a planar shape, in particular it is a plate.
• the contrast element 102 has a curved shape or a shape corresponding to the shape of the welding tip 7.
• the welding tip 7 (in particular the welding element 5) comprises portions manufactured, in particular it is totally manufactured, by means of sintering processes.
• the welding tip 7 (in particular the welding element 5) comprises portions made, in particular it is totally made, of widia (i.e. cemented carbide, carboloy).
• the welding tip 7 and the welding element 5 are made in one piece.
• the welding tip 7 and/or the welding element 5 are manufactured by means of additive production techniques.
• a method for welding to one another a plurality of layers 2 of metal material at least partially overlapped is provided.
• the method comprises the step of providing a plurality of layers 2 of metal material (advantageously of the type described above) at least partially overlapped and applying a welding action on an outer surface of such plurality of layers 2 of metal material at least partially overlapped.
• the welding action is applied providing a welding device 1 comprising a welding element 5 which has, at one end 6 thereof, at least one welding tip 7 (advantageously but not limitedly of the type described above) which can be operated, following the application of an impulsive force, for shifting from a first position in a rest configuration I to a second position in an operating configuration 0, in which said welding tip 7 exerts said welding action proportional to said impulsive force upon said plurality of layers 2 of metal material at least partially overlapped so as to weld them together.
• a welding device 1 comprising a welding element 5 which has, at one end 6 thereof, at least one welding tip 7 (advantageously but not limitedly of the type described above) which can be operated, following the application of an impulsive force, for shifting from a first position in a rest configuration I to a second position in an operating configuration 0, in which said welding tip 7 exerts said welding action proportional to said impulsive force upon said plurality of layers 2 of metal material at least partially overlapped so as to weld them together.
• the method comprises a step of positioning the welding device 1 (provided with the welding element 5 and comprising the welding tip 7) in contact with an outer surface 25 of the plurality of layers 2 of metal material in the area of an overlapping zone 40, where the layers 2 of metal material overlap ( Figures 12 and 13).
• the portion of the overlapping zone 40 in contact with the welding tip 7 determines a welding zone.
• the welding device 1 is disposed relative to the layers 2 of metal material to be welded so that the welding tip 7 (or advantageously the plurality of welding tips 7) is (are) in contact with (in particular pressing without deforming) the outer surface 25 of the plurality of layers 2 of metal material at least partially overlapped to be welded.
• the method further comprises a step of operating the welding device 1 by means of the application of an impulsive force F on said welding element 5 so as to cause the welding tip 7 to exert a welding action (at least partially deforming the layers 2 of metal material in the area of the contact zone 10), which is a function of the impulsive force F, so as to weld together the plurality of layers 2 of metal material.
• the method provides for applying a welding action of the type described above on the plurality of layers 2 of metal material to be welded, in particular (at least) on an outer surface 25 of the plurality of layers 2 of metal material, even more in particular in the area of the contact zone 10, in the area of which there is at least one partial overlapping of such layers 2 of metal material.
• the method provides for the application of an impulsive force F, by means of the pushing means 8 manufactured according to one of the variants described above, on said welding element 5 so that the welding tip 7 (even more advantageously as better explained above, the welding tips 7) transfers such impulsive force F onto the layers 2 of metal material to be welded, exerting a welding action, which is a function of the mentioned impulsive force F, upon the plurality of layers 2 of metal material at least partially overlapped so as to weld them together.
• the step of exerting the welding action is performed by means of a welding device 1 of the type described above.
• the step of operating the welding device 1 takes place by applying an external force (for example manually or as explained above by means of automatic actuation means) on the welding device 1 for operating the pushing means 8 of the welding device 1 so as to cause the welding element 5 to move from the first position to the second position (i.e. from the configuration I to the configuration 0).
• an external force for example manually or as explained above by means of automatic actuation means
• a weld W, W' of a plurality of layers 2 of metal material at least partially overlapped is provided, made according to the method described above or by means of the welding device 1.
• Said weld W, W' comprises a plurality of layers 2 of metal material (advantageously such as the ones described above) at least partially overlapped which are welded (i.e. joined) together according to the method described above or by means of the welding device 1.
• the overall thickness of the layers 2 of metal material outside of the contact zone is greater than the overall thickness of the plastically deformed layers 2 of metal material in the area of the contact zone 10.
• the layers 2 1 , 2 11 , 2 111 , 2 IV welded in the area of the contact zone 10 have a variable thickness, in particular decreasing from the more external layer 2 IV , i.e. the one in the area of the outer surface 25 of the layers 2.
• a power storage device 3 is provided.
• the invention can be applied for the production of power storage devices 3, such as for example lithium (ion or polymer) batteries (such as the one schematically illustrated in Figure 15) or capacitors (such as the one schematically illustrated in Figure 16).
• power storage devices such as for example lithium (ion or polymer) batteries (such as the one schematically illustrated in Figure 15) or capacitors (such as the one schematically illustrated in Figure 16).
• a power storage device 3 comprises at least one power storage unit A (or a battery module A') (in particular, an electrochemical cell, in the case of lithium batteries, or a capacitive unit, in the case of capacitors) which in turn comprises at least two electrode (each provided with at least one terminal tab B) layers E (with opposite polarities) and at least two separator layers S, which at least partly face and are in contact with at least one of the at least two electrode layers E, of which at least one is interposed between the at least two electrodes.
• a power storage unit A or a battery module A'
• an electrochemical cell in the case of lithium batteries, or a capacitive unit, in the case of capacitors
• separator layers S which at least partly face and are in contact with at least one of the at least two electrode layers E, of which at least one is interposed between the at least two electrodes.
• the power storage device 3 comprises a weld according to what is described in the foregoing.
• the power storage unit A comprises a plurality of electrode layers E (in white - anode and cathode) and of separator layers S placed so as to be alternated with one another.
• each electrode E comprises at least one electrode tab B coming out of a main body of the unit A on the same side (as in Figure 15) or on opposite sides.
• the unit A defines a stack composed so that all the tabs belonging to the same electrode (anode or cathode), are aligned and overlapped with one another so that they can be welded to one another.
• the electrode layers E are joined to one another by welding electrode tabs B, advantageously by applying the welding method for welding a plurality of layers 2 of metal material described above, and even more advantageously by using the welding device 1 described above.
• the electrode tabs B are welded to one another by means of a weld W, also known as pre-weld.
• the (at least one) electrode tab B is welded (also) to a terminal metal element T (that acts as positive or negative terminal electric pole of the unit A).
• the electrode tabs B are welded to the terminal metal element T by means of a weld W'.
• the power storage unit A comprises a pair of electrode layers E (anode and cathode) and a pair of separator layers S placed so as to be alternated with one another.
• each electrode E comprises at least one electrode tab B coming out of a main body of the unit A, on the same side or on opposite sides (as in Figure 16). More precisely, the unit A defines a wound element.
• the (at least one) electrode tab B is welded (also) to a terminal metal element T (that acts as positive or negative terminal electric pole of the unit A).
• the electrode tabs B are welded to the terminal metal element T by means of a weld
• the terminal metal element T is a suitable metal bar. In other non-limiting cases, the terminal metal element T is obtained on a (metal) support structure 27 of the storage unit A (in particular of the capacitor) .
• an assembling method for assembling a power storage device 3 is further provided, in particular a prismatic or cylindrical (more precisely a lithium ion) battery, or a capacitor.
• the assembling method comprises a feeding step, during which the abovementioned electrode layers E are fed (on a conveying plane P), each provided with a terminal tab B and the above-described separator layers S.
• the method further comprises a placement step, during which such electrode layers E and separator layers S are disposed so as to at least partly face one another and be alternated with one another in order to form a power storage unit A.
• the placement step entails stacking said electrode layers E and said separator layers S on top of one another alternated with one another.
• the apparatus 100 comprises a stacking device 101 configured to overlap, alternated with one another, the electrodes E and the separators S in order to form the power storage unit A (in particular a stack).
• the placement step entails winding together, beside one another and alternated, said electrode layers E with said separator layers S (to form, for example, a cylindrical cell/battery or capacitor).
• the method comprises a first joining step, during which at least one terminal tab B of the power storage unit A is joined (welded by means of the abovementioned weld W, W') to at least one further metal layer B (thus joining the terminal tabs B to one another in a so-called "pre-weld") or 31 (thus forming the battery module A' in Figure 17).
• the first joining step entails an application sub-step, during which an impulsive welding action (i.e. a welding action according to what is described above by means of the application of an impulsive force F) is applied in the overlapping zone 40, where the terminal tab B and the further metal element B, 31 overlap, by means of a welding tip 7, which is operated following the application of an impulsive force F.
• an impulsive welding action i.e. a welding action according to what is described above by means of the application of an impulsive force F
• F impulsive welding action
• a plurality of electrode layers E is fed, each provided with a terminal tab B and a plurality of separator layers S.
• the terminal tabs B of said electrode layers E having a same polarity are welded to one another by means of said impulsive welding action (forming the weld W of Figure 17, mentioned above as "pre-weld").
• the method comprises a second joining step, during which the terminal tabs B welded to one another are in turn welded to a terminal metal element T by means of said further impulsive welding action (forming the weld W' of Figure 17).
• the power storage unit A or the battery module A', is joined (in particular, electrically connected, i.e. welded by means of the weld W') to the covering case 27.
• first and second joining steps can be both or only one of the two can be performed by means of the welding method for welding a plurality of layers 2 of metal material described above, and even more advantageously by using the welding device 1 described above.
• the first joining step and/or the second joining step entail an application sub-step, during which a welding action is applied according to the welding method for welding a plurality of layers 2 of metal material described above, and even more advantageously by using the welding device 1 described above.
• the power storage device 3 is a lithium battery.
• the power storage device 3 comprising a battery module (corresponding to the module A') which, in turn, comprises (in particular is composed of) an assembly of electrochemical cells (which form the storage unit A) each provided with two terminals B, in particular with two protruding terminal tabs B intended to form, in the power storage device 3, an electrical connection.
• Each electrochemical cell can have, in particular, a flat shape.
• Each cell can comprise, in particular, at least one electrode E (for example an electrode sheet) and/or at least one separator S (for example a separator sheet, known per se and not further described herein) which at least partly overlap.
• the cell can comprise one or more separators and one or more electrodes.
• the cell can comprise two electrode layers E separated by at least one separator layer S.
• Each electrode layer E can comprise a cathode or an anode.
• the cells are stacked on top of one another and the respective terminal tabs B are welded to one another (as schematically illustrated in Figure 15) by applying the welding method for welding a plurality of layers 2 of metal material described above, and even more advantageously by using the welding device 1 described above.
• the abovementioned assembling method entails feeding a plurality of electrode layers E each provided with two terminal tabs B and a plurality of separator layers S, and the placement step entails placing them alternated with one another and stacked on top of one another in order to obtain a plurality of electrochemical cells (which form the unit A of Figure 17), which are then electrically connected to one another in assemblies, by welding the terminal tabs B to one another, by means of the welding method for welding a plurality of layers 2 of metal material described above, and even more advantageously by using the welding device 1 described above (forming the module A' of Figure 17).
• an assembling apparatus for assembling a power storage device 3 of this type, in particular a lithium battery is proposed.
• the assembling apparatus comprises: a frame; a feeding device configured to feed a plurality of electrochemical cells (advantageously made as described above), each provided with two respective terminal tabs B; a stacking device configured to stack the electrochemical cells on top of one another and a welding device 1, advantageously of the type described above, for welding the electrochemical cells to one another, in particular the terminal tabs B of the electrochemical cells to one another, so as to form at least one battery module A' (for example such as the one illustrated in Figure 15).
• the power storage device 3 is a capacitor .
• the battery module A' and the power storage unit A coincide and are composed of a capacitive unit comprising (in particular, composed of) an electrode layer E (cathode and/or anode) provided with two terminal tabs B, advantageously in the shape of a band of electrode material E, and a separator layer S, advantageously in the shape of a band of separator material S, wound beside one another, in particular alternated with one another, around a core (not visible in Figure 16) with an oblong shape, so that from said spiral the two terminal tabs B protrude, which are then joined to a support structure 27 (i.e. a covering case - can).
• the terminal tabs B can be welded to the support structure 27 by means of the welding method for welding a plurality of layers 2 of metal material described above, and even more advantageously by using the welding device 1 described above.
• the assembling method for assembling a power storage device 3 described above entails a winding sub-step during which the band of electrode material E and the separator band S are wound beside one another, in particular alternated with one another, around the abovementioned core with an oblong shape, so that from said spiral the two terminal tabs B protrude, which are then joined to a support structure (as schematically shown in Figure 16).
• an assembling apparatus for assembling a power storage device 3 of this type, in particular a capacitor is further provided.
• the assembling apparatus comprises: a first feeding device for feeding at least one electrode band E provided with two terminal tabs B; a second feeding device for feeding at least one separator band S; a winding device comprising a support element for supporting the abovementioned core with an oblong shape and at least one holding member, which can rotate around the support element and is configured to grab the electrode band E and the separator band S, which face one another and are in contact with one another, and to rotate around the support element so as to obtain a plurality of winding loops around the core with an oblong shape in order to generate a power storage unit A; a closing device configured to wrap said power storage unit A with the above-described support structure 27; and a welding device 1 disposed to weld the power storage unit A to the case; in particular, the terminal tabs B to the covering case 27 advantageously by means of the welding method for
• the welding method and the welding device 1 described above have numerous advantages, among which the following are mentioned.
• the welding method and the welding device 1 for welding a plurality of layers 2 of metal material described above allow obtaining in a simple and quick manner an efficient cold weld between the layers 2 of metal material, which subjected to the welding action described above will tend to deform and penetrate one another (as schematically illustrated in Figure 14) firmly joining to one another.
• the power storage device 3 comprises at least one battery module A', provided with a support structure and with a plurality of electrochemical cells electrically connected to one another and to the support structure, each provided with an electrode layer E and a separator layer S at least partly facing and in contact with the electrode layer E and two terminal tabs B; in which the terminal tabs B are welded to the support structure by means of the method for welding a plurality of layers 2 of metal material described in the foregoing.

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• 2021
  • 2021-11-26 EP EP21834882.9A patent/EP4252309A1/de active Pending
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