APPARATUS AND METHOD FOR MAKING A COIL, PREFERABLY FOR AN ELECTROCHEMICAL CELL INTENDED FOR BATTERY PRODUCTION

Abstract

An apparatus (100) for making a coil (B) comprises a feed unit (2) configured to feed at least one strip-shaped article (N) and a winding unit (1). The winding unit includes a plurality of winding heads (10) and a movement device (3) of said winding heads (10) configured to displace said winding heads (10) along a working path (P). Each winding head (10) is configured to wind said strip-shaped article (N) so as to make said coil (B) and is movable along said working path (P). The feed unit (2) comprises a movable portion (20) configured to be displaced along a substantially horizontal displacement direction (d).

Claims

1. An apparatus for making a coil, preferably for an electrochemical cell intended for battery production, said apparatus comprising: A feed unit configured to feed a plurality of strips suitable for making at least one strip-shaped article, said plurality of strips comprising at least one conductor strip and/or one separator strip, A winding unit which includes: at least one winding head; said at least one winding head being configured to wind said strip-shaped article so as to make said coil, said feed unit comprising a movable portion, comprising a movable inlet section from which said plurality of strips enters, a movable outlet section from which said strip-shaped article exits, a coupling roller of said plurality of strips by means of which said strip-shaped article is made and placed upstream with respect to said movable outlet section, said movable portion being configured to be displaced along a substantially horizontal displacement direction.

2. The apparatus according to claim 1, wherein said movable portion moves according to a translation by performing an alternating rectilinear movement.

3. The apparatus according to claim 1, wherein said winding unit comprises a movement device of said at least one winding head configured to displace said at least one winding head along a working path; said winding head being movable along said working path so that said at least one strip-shaped article is submitted to a substantially constant tension during the winding of said strip-shaped article by means of a respective winding head and as a consequence of the movement of said winding head at least in a segment comprised between said feed unit and said at least one winding head.

4. The apparatus according to claim 3, wherein said movement device and said at least one winding head are kinematically independent with respect to said movable portion.

5. The apparatus according to claim 3, wherein said movement device of said at least one winding head is directly constrained to said movable portion downstream of said coupling roller.

6. The apparatus according to claim 3, wherein said movement device comprises a rotatable body configured to rotate about a rotation axis thereof, said movement device comprising a plurality of arms constrained to said rotatable body and hinged at one end thereof to said rotatable body with allowed rotation about a second rotation axis substantially parallel to said rotation axis and wherein, at an opposite end thereof, a respective winding head is hinged according to a winding axis thereof that is substantially parallel to said rotation axis.

7. The apparatus according to claim 5, wherein said movement device comprises a rotatable body configured to rotate about a rotation axis thereof and said at least one winding head being directly constrained on said rotatable body with allowed rotation about a winding axis substantially parallel to said rotation axis.

8. An apparatus according to one or more of the preceding claims wherein said feed unit is configured so as to define a feed zone for each strip of said plurality of strips defined at least partially upstream of said movable portion wherein each strip of said plurality of strips moves along accumulation segments substantially parallel to each other, and a convergence zone, comprised between said feed zone and said coupling roller and internal to said movable portion, wherein said plurality of strips converges by reducing the mutual distances between each strip up to said coupling roller making said strip-shaped article.

9. The apparatus according to claim 8, wherein a strip of said plurality of strips is fed according to a direction substantially parallel to the displacement direction of said movable portion in said convergence zone.

10. The apparatus according to claim 9, wherein said one strip of said plurality of strips is fed according to a direction substantially parallel to the displacement direction also at a portion of said feed zone.

11. The apparatus according to claim 10, wherein said strip fed according to said direction substantially parallel to the displacement direction also at said portion of said feed zone is a conductor.

12. A method for making a coil, preferably for an electrochemical cell intended for battery production, said coil being made by winding a strip-shaped article said method comprising: Arranging a feed unit comprising a movable portion to feed a plurality of strips to a coupling roller by means of which said strip-shaped article is made, providing at least one winding head winding said strip-shaped article exiting said coupling roller by means of said at least one winding head moving said movable portion along a substantially horizontal displacement direction.

13. The method according to claim 12, wherein said at least one winding head is movable along a working path and comprising moving said at least one winding head such that said strip-shaped article is submitted to a substantially constant tension.

14. The method according to claim 12, wherein said feed unit is configured such that it can move each strip of said plurality of strips along respective accumulation segments substantially parallel to each other in a portion of feed zone defined at least partially upstream of said movable portion, and make said plurality of strips converge into a convergence zone, comprised between said feed zone and said coupling roller and internal to said movable portion, by reducing the mutual distances between each strip of said plurality of strips up to said coupling roller making said strip-shaped article.

15. The method according to claim 14, comprising feeding a strip of said plurality of strips according to a direction substantially parallel to said displacement direction of said movable portion at said convergence zone.

16. The method according to claim 15, comprising feeding said one strip of said plurality of strips in a direction substantially parallel to the displacement direction (d) also at a portion of said feed zone.

17. The method according to claim 16, wherein said strip fed according to said direction substantially parallel to the displacement direction also at said portion of said feed zone is a conductor.

Description

[0412] The characteristics and the advantages of the invention will become clearer from the detailed description of a preferred embodiment example thereof, shown by way of non-limiting example, with reference to the appended drawings wherein:

[0413] FIG. 1 is a schematic, frontal view of the apparatus according to the present invention;

[0414] FIG. 2 is a perspective view of an apparatus made in accordance with the present invention;

[0415] FIGS. 3 to 8 are schematic frontal views illustrating the apparatus according to the present invention during different operating steps;

[0416] FIG. 9 is a further perspective view of the apparatus according to the present invention, with some components removed for illustrative clarity;

[0417] FIG. 10 is a schematic view according to a perspective view of an alternative embodiment of the apparatus according to the present invention;

[0418] FIG. 11 is a schematic illustration showing two discordant directions according to the meaning of the present invention; and

[0419] FIG. 12 illustrates an alternative embodiment of a movable portion of a feed unit of the apparatus according to the present invention, while it is moved to accumulate a quantity of strip,

[0420] FIGS. 13 to 14 are schematic frontal views illustrating the apparatus according to the present invention during different operating steps,

[0421] FIG. 15 is a schematic representation of the apparatus according to the present invention during different operating steps,

[0422] FIG. 16 is a perspective view of the movable portion of the apparatus according to the present invention,

[0423] FIG. 17 is a detail of the perspective view of the invention of FIG. 16.

[0424] With reference initially to FIGS. 1 and 2, an apparatus for making a coil B made in accordance with the present invention is indicated as a whole with 100.

[0425] In preferred embodiments, the apparatus 100 is intended to carry out the winding of a strip-shaped article N intended for the production of electrochemical cells.

[0426] However, it is understood that this represents a possible embodiment example and that the apparatus 100 according to the present invention may be intended for winding strip-shaped articles also intended for different uses, even in areas other than those related to the production of electrochemical cells.

[0427] For example, still in the field of energy storage, the present invention can find application in the production of other rolled components intended for batteries or supercapacitors.

[0428] In some embodiments, such as for example the one illustrated in FIG. 1, the apparatus 100 may be used within a line for the production of coils for electrochemical cells, in which the strip-shaped article N is made by a combination of multiple strips N1, N2, N3, N4, preferably overlapped into layers.

[0429] Such strips preferably comprise at least two conductor strips N1, N3 and two separator layers N2, N4, which are arranged alternated to form the strip-shaped article N.

[0430] In this way the separator strips N2, N4 can allow to keep the two conductor strips N1 and N3 electrically separated from each other as they are spirally wound, forming the coil intended for the electrochemical cell.

[0431] In preferred embodiments, the strips N1, N2, N3, N4 are supplied by special dispensing devices 6. By way of example, FIG. 1 illustrates an embodiment example of the dispensing devices 6 of the separator strips, which can be formed by large-sized coils in which the strip is collected so as to be unwound and then supplied during operation of the apparatus.

[0432] The strips supplied by the dispensing devices 6 are then supplied to a feed unit 2 which, in preferred embodiments, takes care of combining the strips between them in such a way as to form the strip-shaped article N before it is wound by a relative winding unit 1, the characteristics of which will be described in detail below.

[0433] Preferably, the feed unit 2 comprises an inlet section 21 preferably adapted to receive the strips from the respective dispensing devices 6 and an outlet section 22 through which said strip-shaped article N transits out of the feed unit 2 and is fed to the winding unit 1.

[0434] Between the inlet section 21 and the outlet section 22 a feed path 8 for the strips is thus defined. It will be appreciated that the strips, before being supplied to the feed unit 2, can transit through further units for example intended to carry out preliminary processing on the strips. For example, the conductor strips may be submitted to preliminary ablation operations to form a relative outer edge in order to favour the connections with the further conductor portions within the electrochemical cell.

[0435] As previously mentioned, the strips N1, N2, N3, N4 can be combined inside the feed unit 2 so as to form the strip-shaped article N to be wound for making the coil.

[0436] For this purpose, it can be provided that the strips N1, N2, N3, N4 are advanced along different directions to converge towards a coupling roller 23, visible in FIGS. 9 and 17, on which they are all partially wound in such a way that, downstream of said coupling roller 23, there is a single multilayer structure forming the strip-shaped article N.

[0437] In preferred embodiments the strips N1, N2, N3, N4 are fed continuously inside the feed unit 2. In other words, each strip, or possibly one or more of the aforesaid strips, is introduced into the feed unit 2 without ever stopping, proceeding with a speed greater than zero and preferably substantially constant.

[0438] However, there may be the need to provide for interruptions of one or more of the strips forming the strip-shaped article N or to slow down the advancement of one or more of the strips for other operational needs linked to the specific processing being carried out.

[0439] For example, while making coils intended for making electrochemical cells, it can be provided that the strips forming anode and cathode respectively are not present in the terminal portion of the strip-shaped article that is wound to form the coil. In other words, it can be provided that the coil has a terminal and/or initial flap in which only the two separator strips are present overlapped. For this and other purposes, it can be provided for the presence of an accumulation device 4, as shown for example in FIGS. 1, 3, 13 and 14, configured in such a way as to accumulate a quantity of at least one of said plurality of strips N1, N2, N3, N4 between the inlet section 21 and the outlet section 22 of the device.

[0440] With reference to FIGS. 13, 14 and 16, a feed zone ZA and a convergence zone ZC comprised in the operating space of the power unit 2 are respectively identified.

[0441] More in detail, for each strip of the plurality of strips N1, N2, N3, N4 the feed zone ZA is defined at least partially upstream of the movable portion 20, in which each strip of the plurality of strips N1, N2, N3, N4 moves along accumulation segments 81 substantially parallel to each other.

[0442] Furthermore, with particular reference for example to FIG. 16, the convergence zone ZC is comprised between the feed zone ZA and the coupling roller 23 and inside the movable portion 20, wherein the plurality of strips N1, N2, N3, N4 converges by reducing the mutual distances between each strip up to the coupling roller 23 making the strip-shaped article N.

[0443] As illustrated in the embodiment example of FIG. 3, in preferred embodiments the accumulation device 4 comprises at least one movable element 4A configured to vary an overall length of said feed path by movement of said movable element 4A.

[0444] The quantity of accumulated strip can be variable, in the sense that it can be envisaged that the quantity of strip, in terms of length, that is accumulated is variable during the different steps of the process, in order to meet specific needs as mentioned above.

[0445] For this purpose, a device for actuating the accumulation device 4 can be provided which actuates, preferably by displacing it, the accumulation device 4 to vary the accumulated quantity of strip. As illustrated in the example of FIG. 3, the movable element 4A may comprise at least one movable roller 40, on which the strip of which a certain quantity is to be accumulated is wound. The strip is then wound on the movable roller 40 and on at least one fixed roller. In this way, by varying the distance between the two rollers, the length of the path that the strip must travel between the inlet section 21 and the outlet section 22 can be varied, effectively allowing the desired quantity to be accumulated.

[0446] In this way, for example considering the example of FIG. 3, by lowering the movable roller 40 the length of the strip N1 can be increased and, considering a constant or substantially constant advancement speed at the inlet to the feed unit 2, the part of the strip at the outlet section can be slowed down or stopped with respect to the other strips.

[0447] It should also be noted that in preferred embodiments, the action of the movable roller 40, or more generally of the accumulation device 4, can be associated with a holding device 26A of the strip configured in such a way as to slow down or stop feeding one or more of the strips.

[0448] In other words, the action of the accumulation devices 4 can be coordinated with that of the holding device 26A, shown for example in FIGS. 16 and 17, in such a way that the accumulation device 2 accumulates the strip N when the holding device 26A slows down or stops the feeding of the strip.

[0449] For example, in some embodiments the presence of a gripper 26, illustrated for example in FIG. 2, or other similar holding element, acting on the strip at the time when it is required that this is stopped or slowed down may be provided in order to slow down the movement of such a part of strip.

[0450] The gripper 26 can advantageously be movable with respect to the movable portion, in such a way as to adjust the advancement speed of the relative strip by controlling its movement.

[0451] The gripper 26 can also be associated with a relative further cutting device 27 which, if necessary, performs the cut of one of the strips, to create an interruption in the continuity of said strip within the overall strip-shaped article N.

[0452] In preferred embodiments, the further cutting device 27 can occur by means of a knife or by means of another device such as for example a laser ablation system.

[0453] With reference to FIGS. 13 to 17, it can be noted that the movable portion 20 is preferably oriented horizontally and that a displacement direction thereof d and a feed direction f of the plurality of strips N1, N2, N3, N4 are also oriented horizontally. In this case, the holding device 26A, which acts in the convergence zone ZC, operates by holding at least one horizontally oriented strip.

[0454] In more detail, in FIG. 13 this horizontal strip is N1, while in FIG. 15 it is N3, which generally corresponds to a conductor, for example an anode or a cathode.

[0455] According to further embodiments, a lesser or greater number of strips than what is previously described is provided, making different combinations of types of materials used, thicknesses of the relative strips, etc.

[0456] With reference now to FIGS. 1 and 2, the winding unit 1 is arranged immediately downstream of the feed unit 2 so as to receive the strip-shaped article N formed by it.

[0457] Preferably, the strip-shaped article N is fed by being displaced along a feed direction f, which in preferred embodiments corresponds to the direction along which the strip-shaped article N moves once it is formed by combining the individual strips N1, N2, N3, N4 and possibly the direction that it assumes between the roller 23 and the winding unit 1.

[0458] In general, however, it will be possible to define an overall advancement direction of the strip-shaped article N as a function of the characteristics of the feed unit 2 and of the ways in which the strips are combined within it.

[0459] Preferably and with reference to FIGS. 13 and 14, the feed direction f comprises a horizontal segment. Still with reference to FIGS. 13 and 14, according to some embodiments of the present invention the horizontal segment of the feed direction f corresponds to accumulation segments 81 placed upstream of the movable portion 20 and described in more detail below.

[0460] Again with reference to FIGS. 2 and 3, in preferred embodiments, the winding unit 1 comprises a plurality of winding heads 10, each of which allows the strip-shaped article N to be wound according to manners described in greater detail below.

[0461] With reference to the embodiments illustrated in FIGS. 3 to 8 and 13 to 14, the movement device 3 and the movable portion 20 are kinematically independent. In fact, as can be immediately noted, displacements of the movable portion 20 do not directly induce specific movements of the movement device 3 and vice versa. The winding heads 10 are movable within a working path P, which is preferably closed, as schematically shown in FIG. 3.

[0462] The movement of the winding heads 10 is performed by means of a respective movement device 3 through which it is possible to have each head travel along the working path P.

[0463] Still with reference to FIGS. 3 to 8 and 13 to 14, it can be noted how the working path P has a common feature between the allowed movements of the movement device 3 and of the movable portion 20. In this common segment, it is to be understood that the movement device 3 and the movable portion 20 are configured to collaborate synergistically in order to make the coil B always remaining kinematically independent.

[0464] In more detail and with reference to FIGS. 13 and 14, it can be noted that the common segment of the working path P is horizontal and therefore in continuation of the displacement direction d according to some embodiments of the present invention.

[0465] In some embodiments, such as for example the one illustrated in FIGS. 2 and 13, the movement device 3 comprises a rotatable body 30 that can rotate about a rotation axis thereof C.

[0466] The rotatable body 30 supports a plurality of extendable arms 31, which are preferably hinged at one end thereof to the rotatable body 30 and, at an opposite end thereof, a respective winding head 10 is in turn supported.

[0467] Advantageously, the combination of the rotatable body 30 and of the extendable arms 31 allows the winding heads to perform the displacements that are necessary to follow the working path P. In preferred embodiments, this causes the winding heads 10 to move according to a trajectory which includes at least one rotation about the rotation axis C of the movement device 3 and a translation and/or a rotation about a further axis, different from said rotation axis C.

[0468] It can therefore be observed how, in the embodiments illustrated in the figures, the rotation about the further axis is performed through the oscillation of the arms 31 around the axis C1 passing through the end connected to the rotatable body 30.

[0469] However, it is evident that different combinations of such movements can also be envisaged which can be performed both simultaneously and one in succession to the other.

[0470] FIGS. 10, 15 and 16 illustrates an embodiment variant of the present invention in which the winding heads 10 are directly fixed on the rotatable body 30, therefore without using the extendable arms.

[0471] Still with reference to FIGS. 10, 15 and 16 and according to alternative embodiments of the present invention, the rotatable body 30 of the movement device 3 is mounted with allowed rotation directly on the movable portion 20 at an area located downstream of the winding roller 23.

[0472] As can be clearly inferred from FIGS. 10, 15 and 16, in these embodiments the rotatable body 30 is not kinematically independent of the movable portion 20 since a component, for example translational, of the movable portion 20 would result in an equal translational component of the rotatable body 30 to which further relative own displacements could possibly be added.

[0473] In general, according to some embodiments, the rotatable body 30 can advantageously be further movable, in addition to around its rotation axis C, also along the displacement direction d, i.e. the direction along which said rotatable body 30 and, in general, the movement device 3, can be displaced.

[0474] Referring now again to FIG. 2, in some embodiments each winding head 10 supports a gripping device 11 that is configured to grasp a portion of said strip-shaped article N.

[0475] The winding of the strip-shaped article N can thus be obtained by rotation of the gripping devices 11 themselves around a winding axis thereof X. By grasping one end of the strip-shaped article N or, more generally, a portion thereof, and by rotating this end or portion, it is in fact possible to wind the strip-shaped article N obtaining a spiral configuration that forms the coil.

[0476] Referring now also to FIG. 9, each gripping device 11 preferably comprises a pair of pins 12, 13 between which the strip-shaped article N is held. In some embodiments, such as those illustrated in the figure, the pins 12, 13 have a semicircular section. However, it will be appreciated that other shapes may also be provided, for example any polygonal section, a cylindrical section, or even an overall shape of the flat pin.

[0477] At least one of the two pins is movable so as to be able to join the other pin holding said strip-shaped article N between them.

[0478] The pins 12, 13 are arranged substantially parallel to the winding axis X of the strip-shaped article and can also be rotated to perform the winding of the turns.

[0479] In order to allow the pins to grasp the strip-shaped article N, it may be provided that at least one of the two pins is movable along an extraction direction e. In this way, a first pin 12 of the pair can approach the strip-shaped article N during the movement of the relative head 10 along the path P. The second pin 13, which is movable, is instead intended to be arranged in a downstream position along the path P with respect to the fixed pin 12. In this way the strip-shaped article can be comprised between the two pins 12, 13.

[0480] For this purpose, the movement of the extraction direction e of the movable pin 13 is substantially parallel or more generally not perpendicular, with respect to the axis X and perpendicular, or more generally transverse, with respect to the feed direction f of said strip-shaped article N.

[0481] In this way, the second pin 13 can be placed in a position that does not interfere with the approach of the first pin 12 to the strip-shaped article N and it is possible to displace the second pin 13 to a position that holds the article N once the first pin 12 is positioned.

[0482] Advantageously also the first pin 12 can be configured in such a way as to move along the extraction direction e, simultaneously with the second pin 13, in order to allow discharging the coil, as will be illustrated in greater detail below.

[0483] FIGS. 3 to 8 illustrate the movement of the winding heads 10 and, in general, the operation of the present invention in a preferred embodiment.

[0484] Below these figures will be described in relation to two winding heads 10, it being evident that the same concepts will be applicable to an indefinite number of heads.

[0485] A first winding head 10A and a second winding head 10B, the latter one being arranged in an upstream position along the working path P with respect to the first head 10A, are therefore identified in FIG. 3.

[0486] In the condition of FIG. 3, the first winding head 10A is in a position adjacent to the outlet section 22 of the feed unit, in the position in which it receives the strip-shaped article N therefrom. The second winding head 10B is instead arranged along a reset segment P2 of the working path P. This reset segment P2 allows the path P to be closed, and is in particular the segment along which the winding heads return to the beginning of the operative segment P1 after having wound the strip-shaped article, formed the coil and discharged the latter in a discharge zone 7, the latter being schematically indicated in FIGS. 1 and 2. It will be appreciated that the coil B in this discharge zone 7 is discharged by the winding unit 1 to be transported to other units intended for making the cell.

[0487] Preferably the discharge takes place by moving the two pins 12, 13, which are displaced along the extraction direction in such a way as to free the coil B from the relative winding head.

[0488] After the strip-shaped article N has been grasped by the winding head 10A, it continues its movement along the working path at a first portion P11 of the operative segment P1.

[0489] Preferably said first portion P11 is rectilinear and is travelled in a manner concordant to the feed direction f of the strip-shaped article N.

[0490] In some embodiments, the feed unit 2 comprises a movable portion 20, which can be displaced along a displacement direction d and at which the outlet section 22 is formed and on which the coupling roller 23 is preferably fixed.

[0491] More in detail and with reference to FIGS. 13, 16 and 17, the movable portion 20 comprises a movable input section 21from which the plurality of strips N1, N2, N3, N4 enters, a movable output section 22, from which said strip-shaped article N exits, a coupling roller 23 of the plurality of strips N1, N2, N3, N4 by means of which the strip-shaped article N is made and placed upstream with respect to the movable output section 22.

[0492] Still with reference to FIGS. 16 and 17, it can be noted that the movable output section 22is relative to the last step of displacement of the strip-shaped article N before it is wound into the coil by the winding head 10.

[0493] It is clear that in the embodiments according to the present invention in which the winding head 10 is mounted inside the movable portion 20, such as for example shown in FIG. 16, the movable output section 22of the strip will also be internal to the movable portion 20. In embodiments according to the present invention and represented in FIGS. 13 and 14, for example, the displacement direction d of the movable portion 20 is substantially horizontal.

[0494] The movement of the movable portion 20 is carried out by means of motorized displacement devices not shown in the figures which preferably comprise tracks or slides, moved by means of belts or racks.

[0495] FIGS. 13, 14 and 15 show a movable portion 20 that moves in pure horizontal translation according to alternating rectilinear motion.

[0496] In further embodiments relating to the present invention, this alternating rectilinear advancement and backward movement on the same segment can be replaced with a slightly more complex law of motion comprising a first horizontal advancement segment, a second vertical displacement segment, a third horizontal backward segment (equal in modulus to the first horizontal advancement segment but in the opposite direction) and a fourth vertical displacement segment (equal in modulus to the second vertical displacement segment but in the opposite direction) and which allows the movable portion 20 to return to the initial starting point once the expected law of motion has been accomplished.

[0497] In alternative embodiments the displacement direction d forms an angle with respect to the horizontal direction comprised between 30 and 60 and is preferably equal to 45.

[0498] With reference to FIGS. 4, 13 and 16, preferably the feed paths 8 of the strips N1, N2, N3, N4 comprise a respective accumulation segment 81 with variable length which preferably extends between respective pairs of preferably idle diverter rollers 24, 25.

[0499] Preferably the accumulation segments 81 extend substantially parallel to each other and the direction of the strips N1, N2, N3, N4, is diverted by the diverter roller 25 so that each of the strips flows to the coupling roller 23.

[0500] Consistently with what has been previously described, the zone in which the strips N1, N2, N3, N4 downstream of the accumulation segments 81 deviate from the condition of relative parallelism and converge to the coupling roller 23 is defined as the convergence zone ZC.

[0501] In some embodiments, such as the one illustrated in figures from 1 to 10, 13, 14 16 3 17 and, in particular, in FIG. 4, the strip N1 is substantially parallel to the displacement direction d of the movable portion 20 and aligned with the coupling roller 23 and, consequently, the presence of the roller 25 is not necessary.

[0502] An alternative embodiment of the present invention is shown in FIG. 15 in which the strip N3 is substantially parallel to the displacement direction d of the movable portion 20 and substantially aligned with the coupling roller 23.

[0503] Advantageously, the distance between the substantially parallel accumulation segments 81 is such that it is possible to house the previously illustrated grippers 26 and knives 27 between two adjacent strips in the segment comprised between the diverter roller 25 and the coupling roller 23, or in any case in the aforesaid convergence zone.

[0504] In some embodiments one of the rollers of each pair of diverter rollers 24, 25 is supported on the movable portion 20, so as to move integrally with it, as will be illustrated in greater detail below. In this way the length of the accumulation segments 81 of each strip can be simultaneously varied by movement of the movable portion 20.

[0505] During the advancement of the movable portion 20 the feed unit 2 can therefore accumulate a quantity of strip-shaped article N between the inlet section 21 and the outlet section 22.

[0506] In fact, as can be observed from the comparison between FIGS. 3 and 4 and 13 and 14, the length of the accumulation segments 81 and, more generally, of the path that the strips N1, N2, N3, N4 travel between the inlet section 21 and the outlet section 22, is increased by coordinating the advancement of the strips with the displacement of the movable portion 20, effectively accumulating a quantity of the respective strips between these sections.

[0507] Preferably the displacement of the movable portion 20 is associated with the advancement of strips so as not to generate undesired tensions on them. The strips can in fact slide on the diverter rollers 25 while the movable portion 20 is being displaced thus increasing the length of the strip between the roller 24 and the roller 25, without inducing any undesired variations of tension. Preferably the displacement speed of the movable portion 20, if it is concordant to the advancement movement of the strips, will be lower than their feed speed.

[0508] In this way it is possible to avoid pulling the strip during the movement of the movable portion 20, thus making this displacement neutral with respect to the movement of the strips.

[0509] In preferred embodiments, the accumulation segments 81 extend substantially parallel to each other, remaining substantially parallel even during and following the displacement of the movable portion 20 and, consequently, their variation in length.

[0510] This can be achieved by providing that the movable portion 20 is displaced along a displacement direction d substantially parallel to the accumulation segments 81 as shown for example in FIGS. 13 and 14. In this way, when the movable portion is displaced along the direction d, the accumulation segments 81 increase or decrease their length by the same quantity.

[0511] More generally, the displacement direction d may preferably be substantially parallel to the feed direction f and both be substantially horizontal. As previously discussed, the feed direction f can be quite complex and therefore comprise a plurality of segments oriented differently between them among which there is at least a horizontal one.

[0512] It is interesting to note by comparing FIGS. 13 and 15 that for substantially equivalent displacement directions d, i.e. along the horizontal direction, it is always possible for the movable portion 20 to have a specific orientation thereof.

[0513] In fact, it can be noted that according to preferred embodiments the movement direction d corresponds to a pure rigid translation that does not change the relative orientation of the movable portion 20.

[0514] In more detail, it can be noted that in FIG. 13 the movable portion 20 has preferred substantially irregular pentagonal shape 20a, 20b, 20c, 20d 20e with a larger base 20a placed as a horizontal upper side. In this embodiment, the coupling roller 23 is placed near this larger base 20a and the strip N1 is substantially parallel to the displacement direction d of the movable portion 20 and aligned with the coupling roller 23.

[0515] Now, referring to FIG. 15, it can be noted that the movable portion 20 has preferred substantially irregular pentagonal shape 20a, 20b, 20c, 20d 20e with a larger base 20a placed as an inclined upper side with respect to the horizon by about 45 and a substantially horizontal lower base 20d. Also in this case, however, the displacement direction d according to pure translation results to be along the horizontal direction and thus all the parts of the movable portion 20 move integrally.

[0516] In this embodiment, the coupling roller 23 is placed near said lower base 20d and the strip N3 is substantially parallel to the displacement direction d of the movable portion 20 and aligned with the coupling roller 23.

[0517] Alternatively, the same result can be achieved by suitably arranging the rollers 24, 25 between which the accumulation segments 81 extend.

[0518] In particular, in specific embodiments, such as for example the one illustrated in FIG. 12, it can be provided that, unlike the embodiments illustrated in the other figures, both the rollers 24 and the rollers 25 are aligned to each other and aligned with the displacement direction d of the movable portion 20.

[0519] It can therefore be observed that the movement of the movable portion 20 is associated also in this case with a modification in the length of each of the accumulation segments 81.

[0520] In some embodiments, the feed unit 2 comprises, along the feed path 8, one or more alignment devices 82 configured in such a way as to guide the strips N in order to avoid, or in any case limit, transverse deviations thereof during their advancement. For example, the alignment devices 82 may comprise pivoting carriages which, if the strip undergoes a deviation in the transverse direction with respect to its advancement direction, urge the strip in such a way as to bring it back in a rectilinear condition.

[0521] Referring now again to FIG. 4, in some embodiments the movement of the winding head along the portion P11 may be accompanied by a corresponding movement of the movable portion 20 along the displacement direction d.

[0522] It should also be noted that the winding heads 10 and the movable portion 20 can be movable in a coordinated manner. In other words, the movement of the winding heads 10 and of the movable portion 20 takes place synchronously. As previously discussed, such a configuration is not necessarily outside a condition of kinematic independence between the winding heads 10 and the movable portion 20.

[0523] In this way, the distance between the winding head 10 that is winding or more generally holding the strip, and the movable portion 20 of the winding unit 2 can be controlled. Consequently, it will be advantageously possible to provide that the length of the strip-shaped article N comprised between the winding unit 2 and the winding head that is holding it, is minimal or in any case equal to a predetermined distance.

[0524] For example, it can be observed from FIG. 4 that also in this operating position the first head 10A is placed adjacent to the outlet section 22 of the feed unit 2.

[0525] For this purpose, in preferred embodiments, the displacement direction d can be substantially parallel to the first portion P11 of the operative segment P1.

[0526] It will be understood that, as previously mentioned, in the context of the present invention by the term substantially referred to the parallelism with respect to the operative segment Pl along which the winding takes place it is intended to mean that the two directions are parallel except for the deviations linked to the winding of the strip-shaped article N. In fact during the winding of the strip-shaped article N the position of the tangent point of the same on the coil being formed is variable and, unless it is compensated for by a movement of the extendable arms 31, it does not follow a perfectly rectilinear line. This can therefore lead to a deviation from a perfect parallelism. Therefore, as previously illustrated, the term substantially parallel will still indicate a possible deviation by 10 and preferably 5 with respect to a perfect parallelism.

[0527] Along the portion P11 the winding head 10 can also start winding the strip-shaped article N.

[0528] It will be appreciated that this is in particular linked to the ratio between the feed speed v.sub.f at which the strip-shaped article is fed by the feed unit 2 and the displacement speed v.sub.sp at which the winding heads move along the portion P11.

[0529] In fact, if the feed speed v.sub.f is higher than the displacement speed v.sub.sp, in this portion it may be envisaged winding the strip-shaped article N at a winding speed such as to compensate for the difference between the two aforesaid speeds.

[0530] In this way the quantity of strip-shaped article N that is fed is either wound or accumulated as illustrated above. Consequently, the strip-shaped article N can be kept at a substantially constant tension by appropriately acting on the movement speeds of the head while it is winding and/or holding the strip-shaped article N.

[0531] It will be appreciated that the feed speed v.sub.f is preferably determined by the speed at which the dispensing coils that form the dispensing device 6 are rotated to unwind the strip, pushing, and then feeding, the strip in the feed unit 1 and subsequently in the winding unit 3. More generally, this speed can be determined by the mode of actuation of the dispensing device 6.

[0532] At the same time, also winding the strip-shaped article N through the winding heads 10 can contribute to determining the feed speed v.sub.f, with a pulling action on each strip. At most, if the coils, or other dispensing device 6, are not motorized, and therefore are idle, the strip could be advanced only by the winding action.

[0533] The tension of the strip is also adjusted by the balance between the action of the dispensing device 6 and the winding of the strip-shaped article, in a manner conceptually similar to that illustrated in relation to the speeds.

[0534] Referring now to FIG. 5, and in a similar manner in FIG. 14, once a displacement limit position is reached in a direction concordant with the feed direction f, the winding head 10A is displaced in the opposite direction along a second portion P12 of the operative segment P1.

[0535] This type of movement of the movable portion 20 is consistent with the previous description made of the motion as alternating rectilinear.

[0536] The argumentations set forth in relation to FIG. 5 et seq. where the displacement direction d is equal to about 45 apply similarly to the case where the displacement direction d is parallel to the horizon, like in the preferred case of the present invention.

[0537] The movement of the head 10A can be advantageously associated with a corresponding displacement of the movable portion 20 of the feed unit 2.

[0538] During the movement of the winding head 10A in the portion P12 the strip-shaped article N is wound through the head itself, preferably with a winding speed greater than that provided for the portion P11.

[0539] It will be appreciated that the displacement of the winding head 10 while performing such winding takes place in a direction discordant with respect to the feed direction f.

[0540] Also the relative portion P12 is preferably substantially parallel to the feed direction f and, optionally, to the displacement direction d.

[0541] Also in this case the same considerations set out above regarding the term substantially parallel apply.

[0542] The quantities of strips accumulated in the previous step can therefore be wound while the winding head 10A is moving along the portion P12.

[0543] Also in this step, equivalent considerations apply in relation to the feed speed and to the displacement speed of the head made with reference to the portion P11.

[0544] The feed speed v.sub.f, the winding speed v.sub.avv and the displacement speed v.sub.sp will in fact preferably be such as to submit the strip-shaped article N to a substantially constant tension.

[0545] As previously illustrated, in preferred embodiments this can precisely be achieved by providing that the feed speed v.sub.f is substantially equal to the sum of said winding speed v.sub.avv and said displacement speed v.sub.sp.

[0546] It will also be appreciated that advantageously the rotatable body 30 of the movement device 3 proceeds with its rotation motion in a continuous manner, while the arm 31 is rotated in the opposite direction, thus performing a movement that is contrary with respect to that carried out during the movement along the portion P11.

[0547] In other words, along the portion P11 and the portion P12 the arm 31 oscillates forwards and backwards so that the winding head can perform the previously described movement and the winding of the strip-shaped article.

[0548] At a limit position along the segment P12, illustrated in FIG. 6, the first winding head 10A can be moved away with respect to the outlet section 22.

[0549] This movement can take place by movement of the head itself and/or displacement of the movable portion 20.

[0550] Thus, as visible in FIG. 7, a sufficient space may be provided so that a second winding head 10B, arranged upstream with respect to the first head 10A along the path P, can be interposed between the first winding head 10A and the outlet section 22.

[0551] In fact, it should be noted that in preferred embodiments it can be provided that the distance between the first winding head 10A and the second winding head 10B is variable along the working path P, as a function of the operating steps of the apparatus 100.

[0552] Thanks to this characteristic, it is possible to obtain the configuration illustrated by way of example in FIGS. 7 to 9 and 17, in which the two heads 10A and 10B are at a minimum distance such as to allow the positioning of a cutting element 51 of the cutting device 5 between them and the second head 10B is in turn at a predetermined distance, preferably substantially equal to the minimum distance from the movable portion 20 and, more generally, from the feed unit 2.

[0553] The two heads are furthermore preferably aligned along the feed direction f of the strip-shaped article N during the working segment in which the cut is made. It will in any case be appreciated that a perfect alignment along the feed direction f is not necessarily provided, it being sufficient that they are positioned at a close distance from each other and one more upstream than the other with respect to the outlet section 22 of the strip.

[0554] In this way, it is possible to grasp by means of the gripping device 11 of the second winding head 10B a relative portion of the strip-shaped article N, as can be observed from FIGS. 9 and 17 and according to what is described above.

[0555] The portion of strip-shaped article N can in particular be grasped according to what is illustrated above, by using the pair of pins 12, 13.

[0556] In this condition the strip-shaped article N is wound to form the coil B on the first winding head 10A and simultaneously grasped by the second winding head 10B.

[0557] In other words, the strip-shaped article N is simultaneously in the grip both on the first winding head 10A and on the second winding head 10B.

[0558] Moreover, again at this position it is possible to perform the cut of the strip-shaped article N at an intermediate position between the first winding head 10A and the second winding head 10B.

[0559] For this purpose, a cutting device 5 can be provided which is configured in such a way as to cut said strip-shaped article N at a position downstream of said feed unit 2 and, advantageously, in the aforesaid position.

[0560] In fact, as can be observed from the illustrated embodiment examples, the cutting device 5 advantageously cuts the strip-shaped article N, when the respective winding head 10 is positioned at said predetermined distance from said feed unit 2, advantageously substantially equal to the minimum distance compatible with the kinematic mechanisms that cause the movement of the winding heads 10.

[0561] As already illustrated, concurrently with the cut, the second winding head 10B is approached to the first winding head 10A, being advantageously at the minimum reciprocal distance along the working path P when the strip-shaped article N is cut.

[0562] The cutting device 5 is illustrated in a preferred embodiment thereof in FIGS. 9 and 17.

[0563] Preferably the cutting device 5 comprises a main body 50 which supports a cutting element 51.

[0564] In some embodiments the winding head 10 comprises an abutment element 14 placed in such a position that the strip-shaped article N is interposed between the abutment element 14 and the cutting device 5.

[0565] The abutment element 14 preferably has a seat 14A configured so as to receive the cutting element 51.

[0566] In this way, when the cutting device 5 is approached to the abutment element 14, the main body 50 of the cutting device 5 may abut the abutment element 14, with the strip-shaped article N interposed, and the cutting element 51 may be received in the seat 14A, generating a pressure on the strip-shaped article N sufficient to obtain the cutting thereof.

[0567] It should be noted that, according to embodiments of the present invention, upstream of the cutting operation of the strip-shaped article N it is provided that the conductor strips N1, N3 are interrupted and their advancement is stopped or slowed down by means of the gripper system 26 illustrated above.

[0568] Such embodiments are particularly advantageous in the case where the displacement direction d is horizontal since in that case there would be at least a portion of at least one strip N1, N3 constrained by means of the gripper system 26 which is oriented horizontally.

[0569] In this way the cut performed by the device 5 can only affect the separator strips N2, N4 which form the strip-shaped article N following the interruption of the conductor strips.

[0570] In particular, it can be noted by way of non-limiting example in FIGS. 7 and 8 the action of the grippers 26 on the conductor strips and the displacement of the movable rollers 40 with respect to the position of FIG. 6, in such a way as to accumulate the strip according to what has been previously illustrated.

[0571] In some embodiments the cutting device 5 is also movable in a direction substantially parallel to the feed direction f. In general it can be provided that the cutting device is movable with at least one component substantially parallel to this direction. For example, the cutting device 5 can be supported on the movable portion 20 or movable integrally therewith. In this way it will be possible both to approach the cutting device 5 to the abutment element 14, and to displace it in a synchronized manner to the strip-shaped article N. In other words, the cutting device 5 copies the movement of the strip-shaped article N, moving synchronously with it when performing the cutting operation.

[0572] Also thanks to such characteristics it is possible to envisage that the strip-shaped article N fed with feed speed v.sub.f is constantly greater than zero, and preferably substantially constant, it being possible for the cut to be performed while the strip-shaped article is also moving.

[0573] It should also be noted that the strips forming the strip-shaped article N can also be made to advance continuously inside the feed unit 2. In embodiments in which the interruption of the conductor strips, or of other strips forming the strip-shaped article, is provided, the continuous advancement will preferably be associated with the possibility of accumulating the strip. Instead, with regards to the strip or the strips for which no interruptions are envisaged, this/these can be made to advance continuously through the outlet section 22, in continuity with the strip-shaped article N.

[0574] Once the strip-shaped article N has been cut, two flaps remain defined, one associated with the first winding head 10A that forms the terminal part of the coil wound therein, and one associated with the second winding head 10B that forms the initial part of the coil B that will be subsequently wound.

[0575] Preferably, the process for making the coil B provides for a third portion P13 of the operative segment P1, preferably substantially parallel to said first and second portion P11, P12 and along which the winding head 10A is displaced after cutting the strip-shaped article N.

[0576] In preferred embodiments, the winding head moves again in a direction concordant to said feed direction f along said third portion P13.

[0577] Preferably said movement device 3 is configured in such a way that when the first winding head 10A travels along said third portion P13, the second winding head 10, which has advantageously just grasped the strip-shaped article N, travels along the first portion P11 performing, in sequence, the steps described above in relation to the first winding head 10A.

[0578] Along the portion P13, on the other hand, the first winding head completes the winding of the flap of the strip-shaped article N which was created after the cut, ending to make the coil B.

[0579] As previously illustrated, the winding of the strip-shaped article N to make the coil B can take place in each of the three portions P11, P12, P13.

[0580] Preferably, the winding takes place mainly, i.e. for a greater percentage quantity, along the second portion P12.

[0581] However, the winding may take place partially also in the other portions.

[0582] In fact, in preferred embodiments, the winding of the strip takes place for a quantity comprised between 5% and 15%, preferably 10%, of the overall length of the strip-shaped article forming a single coil along the first portion P11, for a quantity comprised between 70% and 90%, preferably 80%, along the second portion P12 and for a quantity comprised between 5% and 15%, preferably 10%, along the third portion P13.

[0583] The displacement of the first winding head 10A then continues until it arrives at the discharge zone 7, where the coil B is discharged from the winding unit 1.

[0584] In some embodiments, the apparatus 100 can comprise further working units 60 at which the winding head 10 passes through with the coil B before arriving at the discharge zone 7.

[0585] By way of example, the further working unit 60 can comprise a folding device configured to fold the two opposite axial ends of the coil. It can in fact be provided that the conductor strips each protrude axially, the one on one side and the other on the other, and are folded in such a way as to form a single conductor portion intended to be connected to an anode/cathode end in the cell once it is assembled.

[0586] In some embodiments, the application of a closing element of the coil B can also be provided, which closing element is configured in such a way as to prevent it from unwinding once it is discharged from the winding head 10. Such a closing element may for example be represented by a strip applied circumferentially to the coil in order to close the terminal flap of the strip-shaped element.

[0587] After having discharged the coil, the winding head 10A starts passing through along the reset segment P2 in order to be displaced from a discharge position to a gripping position in which the winding head 10 can grasp the portion of the strip-shaped article N as previously illustrated.

[0588] The steps described above can therefore be repeated cyclically for each of the included winding heads 10 of the winding unit 1.

[0589] As mentioned above, FIG. 10 illustrates a possible illustrative variant of the apparatus according to the present invention.

[0590] In this variant it is provided that the movement device 3 moves integrally with the movable portion 20 of the winding unit 2.

[0591] For this purpose, the movement device 3 can be rotatably supported around the rotation axis C on the movable portion 20.

[0592] In the embodiments in which the movement device 3 can move as a whole, like in the illustrated example in which it moves along the displacement direction d, it can therefore be provided that the winding heads 10 remain in a substantially fixed position with respect to the rotating body 3 and that, consequently, their mutual distance remains unchanged.

[0593] In other words, the movement heads 10 may in this case be displaced, in addition to rotating on themselves for winding the strip-shaped article N, also following the movement of the rotating body of the movement device 3, preferably the linear displacement thereof. In the embodiment illustrated in FIG. 10, as well as more generally others in preferred embodiments not illustrated, such movement includes both the rotation about the axis C, and the translation along the displacement direction d.

[0594] However, it will be appreciated that, more generally, the movement of the movement heads 10 can in this case be caused by any rotation and any translation or further rotation, always in addition to the rotation made to wind the strip-shaped article N.

[0595] However, these movements do not cause a variation in the mutual distance between the winding heads 10.

[0596] However, a combination may be provided between this embodiment and those previously described wherein the distance of the heads is variable.

[0597] More generally, all the elements described so far in relation to the embodiment illustrated in FIG. 10 may be combined with all the possible embodiments provided for by the present invention and described above.

[0598] It goes without saying that, in order to meet specific and contingent application needs, a person skilled in the art will be able to make further modifications and variants that are nevertheless within the scope of protection as defined by the following claims.