CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent applications no. 102020000031487 filed on December 18, 2020, and no. 102021000009251 filed on April 13, 2021, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE ART

The present invention relates to a method and apparatus for winding a plurality of bands.

In particular, the present invention finds advantageous but not exclusive application in the production of an electrical energy storage device to which the following description will make explicit reference without thereby losing generality. More particularly, the present invention finds advantageous but not exclusive application in the production of a cylindrical battery or a capacitor.

BACKGROUND OF THE INVENTION

In the field of manufacturing electrical energy storage devices, and in particular cylindrical batteries or capacitors, it is known to feed, by means of respective feeding units, the electrode bands and the separator bands along different feeding paths which all converge to a rotating winding core which is configured to retain and wind the electrode bands and the separator bands which are arranged interspersed between them, generally around an oblong support, so as to form a winding.

In detail, the known winding methods and apparatuses entail firstly feeding the separator bands to the winding core and then, only when the separator bands are gripped around the winding core (i.e. only after at least a couple of turns have been made around the winding core), feeding the electrode bands between the separator bands. In this way, the electrode bands, before or after being cut to the desired length, are retained and dragged in rotation by the separator bands so as to form a winding. Before the winding is finished, the electrode bands are cut and at least one further closing turn is made with the separator bands. Once the winding has been finished and the separator bands have been cut, the winding is closed for example by means of an adhesive tape (in what is known as the taping operation).

Even in more detail, the winding core is typically mounted on a rotating platform which is arranged and configured so that at each step of rotation of said rotating platform the winding core is moved between a winding station, where the winding is formed, a closing station, where said formed winding is closed (taping), and a discharge station, where the closed winding is discharged (unloading).

During the passage of the winding core from the winding station to the closing station, at least the separator bands are cut so as to finish the winding. Once the cut has been made, a cut flap is caused to return by the winding core that has just arrived at the closing station and rewound to form the last layers of the (previously formed) winding before proceeding to the closure thereof; whereas the other cut flap is caused to return to the winding station and wound around a further winding core (empty and arrived in the meantime in the winding station by means of a rotation of the rotating platform) to form the first layers of a new winding.

However, these known winding methods and apparatuses have certain drawbacks, among which we mention the following.

The formation of a winding, in particular a cylindrical electrical energy storage device, by means of known winding methods and apparatuses entails a high use of separator band, even in areas where this separator band is not actually useful, i.e. it does not perform its function of separating the electrode bands. In fact, the first turns of the winding made with the separator bands of the flap of freshly cut separator band, as well as the last turns of the winding made with the other flap of freshly cut separator band, are parts of the winding that are not energetically productive as they are entirely formed by separator bands, with no electrode bands interposed between them.

This implies an increase in the overall dimensions and times to produce the winding, and a waste of separator band, with consequent disadvantages in terms of costs and production time. SUMMARY

In accordance with the present invention, there are provided a winding method and device, in particular to form an electrical energy storage device, according to what is claimed in the attached independent claims, and preferably, in any one of the claims directly or indirectly dependent on the independent claims.

Claims describe preferred embodiments of the present invention forming an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be now described with reference to the enclosed drawings, which show some exemplary non- limiting embodiments thereof, wherein:

Figures 1 and 1A show two schematic views of a winding apparatus in accordance with two embodiments of the invention;

- Figures 2 to 5 show part of the winding apparatus of Figures 1 during successive steps of the operation of winding a band;

Figures 6 and 6A show two schematic views of a winding apparatus in accordance with two other embodiments of the invention;

- Figures 7 to 10 show part of the winding apparatus of Figures 6 during successive steps of the operation of winding a band;

Figures 11 and 12 show on an enlarged scale, respectively, a perspective view and a side view of part of the winding apparatus of Figures 1 and 6 to better visualize how a band is guided by a guiding device of the winding apparatus at a winding core of the same winding apparatus; and

- Figures 13 and 14 are views similar to Figures 11 and 12, respectively in a successive step of the winding process, wherein the winding core is operated to retain and wind a band;

Figures 15 and 16 show on enlarged scale, respectively, a perspective view and a side view of part of the winding apparatus of Figures 1A and 6A to better visualize how a band is guided by a guiding device of the winding apparatus at a winding core of the same winding apparatus;

- Figures 17 and 18 are views similar to Figures 15 and 16, respectively in a successive step of the winding process, wherein the winding core is operated to retain and wind a band;

Figures 19 is a perspective view of the guiding device of the winding apparatus shown in Figures 1A, 6A;

- Figure 20 is a side view of the guiding device of Figure 19;

- Figure 21 is an enlarged scale and cross-sectional view of part of the guiding device of Figure 19;

Figures 22 and 23 are two longitudinal section views, along two different section planes, of the side of the guiding device of Figures 19; and

- Figure 23A is an enlarged scale representation of part of Figure 23.

DETAILED DESCRIPTION

In the attached Figures, 1 denotes as a whole a winding apparatus 1 for winding one or more bands onto themselves to form a winding 2.

In particular, the following description will refer explicitly to the advantageous but not exclusive use of the winding apparatus 1 in the production of electrical energy storage devices, and even more particularly in the production of capacitors or cylindrical or oval rechargeable batteries, for example of the "jelly roll" type. In this case, advantageously but not in a limiting sense, the winding apparatus 1 is used to wind two electrode bands 3, an anode and a cathode, and two separator bands 4 which are arranged alternately with each other so as to form a battery or a capacitor, or more particularly a battery module or a capacitive unit of a capacitor.

The winding apparatus 1 comprises a rotating winding core 5 (e.g. a mandrel) which is configured to retain and, in use, to drag in rotation at least one electrode and/or separator band 3, 4 so as to form a winding 2, a first feeding unit 7 which is configured to feed at least one separator band 4, typically a pair of separator bands 4, to the winding core 5, a second feeding unit 8, which is independent of the first feeding unit 7, and which is configured to feed an electrode band 3, e.g. the cathode, to the winding core 5, and (advantageously but not in a limiting sense) a third feeding unit 9, which is independent of the first and second feeding unit 7 and 8, configured to feed a further electrode band 3, e.g. the anode, to the winding core 5.

Advantageously but not in a limiting sense, the winding apparatus 1 comprises a control unit CU (per se known and schematically shown in Figures 1, 1A, 6 and 6A) which is configured to operate said first, second and third feeding unit 7, 8 and 9 to feed the electrode bands 3, 4 and/or separator bands to the winding core 5 so that one of the electrode bands 3 (typically the cathode) is fed between the two separator bands 4 and the other electrode band 3 (typically the anode) is arranged outside the two separator bands 4 thereby ensuring the interposition of at least one separator band 4 between the two electrode bands 3.

In detail, in the advantageous but non-limiting embodiment shown in Figures 1 to 10 and 1A, the first feeding unit 7 is configured to feed a pair of separator bands 4 to the winding core 5. In this case, the first feeding unit 7 comprises a spacing device 10 which is configured to keep the separator bands 4 spaced apart when feeding the winding core 5, i.e., during their advancement along an advancement direction X towards the winding core 5. In this way, one of the two aforementioned electrode bands 3 may be introduced between the separator bands 4, once the separator bands 4 are gripped to the winding core 5, in particular once these separator bands 4 have been wound for at least a couple of turns around the winding core 5.

According to some advantageous but non-limiting embodiments (such as those shown, see in particular Figures 1, 1A, 6 and 6A), the spacing device 10 comprises a plurality of rollers 11, advantageously but not necessarily motorised, which can be moved away and closer to each other for guiding the separator bands 4 which are spaced apart from each other when advancing along the aforementioned advancement direction X towards the winding core 5 so that one of the electrode bands 3 (preferably the cathode) can be introduced (by means of the respective feeding unit 8) between said open separator bands 4.

According to alternative embodiments not shown, the spacing device 10 may comprise motorised grippers each configured to grasp and guide the separator bands 4 which are spaced apart from each other when advancing along the aforementioned advancement direction X.

Advantageously but not in a limiting sense, the second and third feeding unit 8 and 9 comprise guiding means 12 for guiding the electrode bands 3 until near the winding core 5.

Advantageously, but not in a limiting sense, the guiding means 12 can be operated to move with respect to the winding core 5 by respective motor means 13 (of known type and schematically shown in Figures 1 to 10, and 1A), to adjust the position and/or the speed of introduction of the electrode band 3 to the winding core 5. In detail, the guiding means 12 can be operated to perform at least one translation towards or away from the winding core 5 and, advantageously but not in a limiting sense, also a rotation, so as to adjust the position (i.e. the inclination of the point) of feeding (introduction) of the electrode band 3, for example as a function of the diameter of the winding 2 that is intended to be obtained, of the dimensions (thickness) of the electrode and/or of the separator bands 3, 4.

According to some advantageous but non-limiting embodiments (such as the one shown in Figure 1 and 1A), the guiding means 12 of each feeding unit 8 and 9 comprise (in particular, they are constituted by) at least one pneumatic gripper 14 which is adapted to take and guide the electrode band 3 being fed to the winding core 5 and is movable closer or away with respect to the winding core 5, thanks to the aforementioned motor means 13, so as to vary the speed and the position of feeding (introduction) of the electrode band 3 to the winding core 5.

With particular reference to Figures 11 to 18, the winding core 5, intended to drag in rotation and wind the electrode and/or separator bands 3, 4, comprises two rotating elements 16 which are arranged in two different and parallel planes (e.g., horizontal) and are reciprocally movable, preferably along said planes (in particular, perpendicularly to the advancement direction X), between a rest configuration (see Figures 11, 12, 15 and 16), wherein the rotating elements 16 are offset from each other, and a winding configuration (see Figures 13, 14, 17 and 18), wherein the two rotating elements 16 are at least partially facing so as to retain between them and, in use (i.e., once caused to rotate), to drag in rotation, at least one of the electrode and/or separator bands 3, 4 so as to form the winding 2.

According to the non-limiting embodiments shown, each of the rotating elements 16 has a semicircular crosssection and the two rotating elements 16 are arranged specularly with the flat face of each of the rotating elements 16 that is turned towards the other rotating element 16.

Advantageously but not in a limiting sense, the winding core 5, in particular each rotating element 16, can rotate around a rotation axis R, which (advantageously) is fixed and transverse (perpendicular) to the advancement direction X (see Figures 13 and 14). In detail, in the preferred but non-limiting embodiments shown, the feeding paths of the electrode and/or separator bands 3, 4 (i.e. the paths along which the respective feeding units 7, 8 and 9 feed the electrode and/or separator bands 3, 4) are arranged in a plane perpendicular to the rotation axis R of the winding core 5 (as shown in Figures 1, 1A, 6 and 6A).

Advantageously, but not in a limiting sense, in the passage from the rest configuration to the winding configuration the rotating elements 16 are movable along a direction Y, which is orthogonal to the advancement direction X and parallel to the rotation axis R. During winding, the rotating elements 16 are brought closer to each other up to the winding configuration (compare Figures 11 and 13 and Figures 15 and 17 between them) and once facing each other in order to transversally constrain the electrode and/or separator band(s) 3, 4 are caused to rotate in a counter-clockwise direction (see Figures 1, 1A, 6, 6A, 14 and 18), or alternatively in a clockwise direction, so as to exert a winding action upon the band(s) 3, 4. Advantageously, but not in a limiting sense, the rotating elements 16 can be caused to translate and rotate by motor means (per se known and not shown, for example by an electric motor). Alternatively, each of the rotating elements 16 may be operated by relative motor means independently of the other.

Additionally, advantageously but not in a limiting sense, the winding core 5 comprises at least one pneumatic counter-roller (not visible in the attached Figures e) configured to hold the electrode and/or separator band(s) 3, 4 in position during the rotation of the winding core 5 itself.

The winding apparatus 1 further comprises at least one cutting unit 17 which is configured to cut at least the separator bands 4 to a desired length.

Advantageously, but not in a limiting sense, according to the embodiments shown in Figures 1 to 14, the winding apparatus 1 comprises three similar cutting units 17, 17' and 17'’: one (the cutting unit 17) intended to cut the separator band(s) 4, and the other two (the cutting units 17' and 17'') intended to cut each of the two electrode bands 3.

Each of said cutting units 17, 17' and 17'’ comprises a cutting element 18, 18' and 18'', advantageously but not in a limiting sense a cutting knife, which can be operated so as to intercept and cut the band(s) 3, 4 and a countering plate (anvil) 19, 19', 19'’ to counter, in use, the cutting element 18, 18' and 18''. Each cutting unit 17, 17' and 17'’ further comprises a moving assembly which is configured to move the cutting element 18, 18' and 18'’ and the countering plate (anvil) 19, 19', 19'’ parallel to the advancement direction X (see Figures 1 to 14). According to some advantageous but not exclusive embodiments, the cutting element 18, 18' and 18'’ is moved by a linear drive (of known type) and the countering plate (anvil) 19, 19', 19'’ is moved by another linear drive. Alternatively, the countering plate (anvil) 19, 19', 19'’ and the cutting element 18, 18' and 18'’ could be moved by the same linear drive.

According to some advantageous but non-limiting embodiments (such as those shown), the cutting units 17' and 17'’ are part of the respective feeding units 8 and 9 and are moved by the same motor means 13. In other words, in this case, the moving assembly of the cutting units 17' and 17'’ coincides with the motor means 13.

Each cutting unit 17, 17' and 17'’ further comprises a control unit CU, which advantageously but not in a limiting sense coincides with the control unit CU of the entire winding apparatus 1, which is configured to control the operation of the cutting element 18, 18' and 18'’ and of the moving assembly so that the cutting element 18, 18' and 18'’ is operated to cut the electrode and/or separator band(s) 3, 4 only when its advancement speed is similar to the advancement speed of the band 3 or 4 it is intended to cut.

This allows to accurately perform a speed-following cut (so-called on the fly), i.e. while band(s) 3 or 4 is/are advancing, avoiding the risk of damaging the band 3 or 4 thanks to the elimination of the relative speed between cutting element 18, 18' and 18'’ and band(s) 3 or 4.

With particular reference to the attached Figures, the feeding unit 7 further comprises a guiding device 20 which, in turn, comprises a lower guiding element 21 and an upper guiding element 22 which are facing each other and reciprocally movable between an open position (see Figures 1, 1A, 5, 6, 8) wherein the lower guiding element 21 and the upper guiding element 22 are at a first distance from one another and a closed position (see Figures 2, 4, 5, 7, 9-14), wherein the lower guiding element 21 and the upper guiding element 22 are at a second distance from one another, which is smaller than the first distance, and exert a gripping action upon the separator band(s) 4 that is such as to hold the separator band(s) 4 in position and guide it.

In detail, the guiding device 20 is movable along the advancement direction X of the separator band(s) 4. Furthermore, advantageously, the guiding device 20, in the embodiments shown in Figures 1 to 14, is adapted to guide the separator band(s) 4 between the cutting unit 17 and the winding core 5; while in the embodiments shown in Figures 1A, 6A, and 15 23, it is adapted to guide the separator band(s) 4 up to the winding core 5.

Advantageously, but not in a limiting sense in the embodiments shown in Figures 1 to 14, the countering plate (anvil) 19 is integral with the guiding device 20, and in particular with the lower guiding element 21.

Furthermore, the feeding unit 7 comprises a (advantageously but not in a limiting sense) linear drive 23 which is configured to move the guiding device 20 and the countering plate (anvil) 19 along the advancement direction X; and the cutting element 18 is arranged at the top of the advancement plane of the separator band(s) 4 and is movable in the advancement direction X, and in particular (also) in a direction Z orthogonal to said advancement direction X, by a further (advantageously but not in a limiting sense) linear drive 24. Alternatively, the countering plate (anvil) 19 could be moved by the drive 24 together with the cutting element 18, or by a further drive (distinct from the drives 23 and 24).

In any case (in Figures 1 to 14), the control unit CU is configured to synchronise the cutting element 18 and the countering plate (anvil) 19 with the advancement of the separator band(s) 4, i.e. in order to operate the cutting element 18 and the countering plate (anvil) 19 so as to perform the cut only when the advancement speeds of the cutting element 18 and of the separator band(s) 4 are the same so as to make a "cut on the fly" as explained above.

Advantageously, the lower guiding element 21 and the upper guiding element 22 are configured so that in a closed position between them there is left a cavity 25 defined, which is configured to receive the winding core 5 (see in particular Figures 2, 7, 16 and 17).

In detail, in the advantageous but not exclusive embodiments shown in Figures 1 to 14, the lower guiding element 21 and the upper guiding element 22 are "L"-shaped and comprise, respectively, a main body 26, 26' and a gripping portion 27, 27’.

Even in more detail, the gripping portion 27 of the lower guiding element 21 extends transversely with respect to the main body 26 thereof of the lower guiding element 21 and protrudes from said main body 26 towards the upper guiding element 22. Similarly, the gripping portion 27' of the upper guiding element 22 extends transversely with respect to the main body 26' thereof of the upper guiding element 22 and protrudes from said main body 26' towards the lower guiding element 21.

In this case, advantageously, the gripping portions 27, 27' each comprise an end wall 28, 28'. These end walls

28, 28' are configured to exert, in the closed position, the aforementioned gripping action upon the separator band(s) 4.

Furthermore, advantageously, the guiding device 20 further comprises a support member 29 (see Figures 11 to 23) carrying the lower guiding element 21 and the upper guiding element 22 and is configured to allow the reciprocal movement of said guiding elements 21 and 22 between the aforementioned open position and the aforementioned closed position. In the advantageous but not exclusive embodiment partially shown in Figures 11 to 14, the support member 29 comprises (is constituted by) two parts one (the lower one) which is fixed and the other (the upper one) which is movable by the aforementioned linear drive and configured to achieve a shape coupling with the other part (the lower one) in the closed configuration. Thus, in this case, the lower guiding element 21 is fixed and the upper guiding element 22 moves towards or away with respect to the lower guiding element 21. It is understood that according to alternative embodiments not shown both guiding elements 21 and 22 could be movable in order to move closer or away to/from each other.

The aforementioned cavity 25, which is intended to receive the winding core 5 during the winding operation, is delimited at the bottom and at the top by an inner wall 30, 30' of the lower main body 26 and of the upper main body 26', respectively (see Figures 11-23), and laterally by the inner walls 31, 31' of the lower gripping portion 27 and of the upper gripping portion 27', on one side, and by the support member 29, on the other side; whereas in the embodiment shown in Figures 15 to 23 in the embodiments shown in Figures 11 to 14 above the cavity 25 is delimited laterally by the protuberances 36 and 36' on one side, and by the gripping portions 27 and 27’’, on the opposite side.

According to the advantageous but non-limiting embodiments shown in Figures 1 to 14, the end walls 28, 28' of the gripping portions 27 and 27' each comprise at least one respective pressing element (per se known and not visible in the attached Figures) which is configured to exert the aforementioned gripping action upon the separator band(s) 4. In particular, in accordance with the embodiments shown in Figures 1 to 14, said pressing elements, which may, for example, be rollers or prismatic elements, are configured to exert a gripping action upon the separator band(s) 4 that is such as to retain it/them while it/they advance (s) from the cutting unit 17 to the winding core 5 but, at the same time, which is less than the winding action transferred by the rotating elements 16 on the separator band(s) 4 when winding, so as to allow the winding core 5 (and in particular the rotating elements 16, once arranged inside the cavity 25 in winding configuration and operated to rotate) to remove the separator band(s) 4 from the gripping portion 27, 27', in particular from the end walls 28, 28', of the guiding device 20 without damaging it and causing it to rotate.

The control unit CU is, in fact, configured to cause the rotation of the rotating elements 16 that are arranged in the winding configuration, only when the winding core 5 is inside the cavity 25 and the lower guiding element 21 and the upper guiding element 22 are in the closed position. In other words, the winding of the separator and/or electrode band(s) 4, 3 takes place after the guiding device 20 in the closed position has guided the separator and/or electrode band(s) 4, 3 in the area of the winding core 5. In detail, the guiding device 20 is moved until the cavity 25 is in the area of the winding core 5 (see Figures 11 and 12), at which point the rotating elements 16 of the winding core 5 are operated to pass to the winding configuration and caused to rotate in order to drag the separator/electrode band(s) 4, 3 in rotation (see Figures 13 and 14).

With particular reference to Figures 1, 1A, 6 and 6A, advantageously but not in a limiting sense, the winding apparatus 1 comprises: a closing device (per se known and not further described nor shown herein) which is arranged at a closing station B and configured to close the winding 2 and a discharge assembly (per se known and not further described nor shown herein) which is arranged at a discharge station C and configured to discharge said winding 2.

In this case, advantageously, the winding core 5 is movable between a winding station A, wherein it receives the bands 3, 4 from the respective feeding units 7, 8 and 9 and winds them (as explained above) to form the winding 2, the closing station B, where said winding 2 is closed by the closing device, and the discharge station C, where the discharge assembly discharges said winding 2.

Even in more detail, the winding apparatus 1 advantageously comprises a rotating platform 32 (schematically shown in Figures 1 and 6) carrying the winding core 5 and which can rotate around a vertical axis so that at each step of rotation of said rotating platform 32 the winding core 5 is transferred between the aforementioned winding, closing and discharge stations A, B, C. In accordance with some embodiments (such as the one shown in Figure 6), the winding station A and the closing station B are aligned with each other along the advancement direction X and the cutting unit 17 is arranged between the winding station A and the closing station B. In this case, with reference to Figures 2 to 5, the separator band(s) 4 is cut once a first winding 2 is finished, i.e. as the winding core 5 passes from the winding station A to the closing station B (thanks to the rotation of the rotating platform 32) and a further winding core 5 arrives (from the discharge station C) at the winding station A to form a second winding 2. In particular, in this case, the guiding device 20 guides the separator band(s) 4 to the winding unit 5 at the winding station A (see Figures 2 - 4) and then, once the cut has been made, it returns from the cutting unit 17 back to the winding station A (as shown schematically in Figures 5) to form a second winding 2. This makes it possible to form the first layers of this second winding 2 with the freshly cut separator band(s) 4, which is wound around a further winding core 5 so that it can receive and drag in rotation the electrode bands 3. Compared to known winding apparatuses, this allows a reduction in the consumption of separator band 4 and a speeding up of the process for the production of a winding 2.

According to alternative embodiments (such as the one shown in Figure 1), the cutting unit 17 is arranged upstream of the winding station A, in particular outside the rotating platform 32. In this case with reference to Figures 7 to 10, the guiding device 20 guides the separator band(s) 4 firstly in the area from the winding station A where the winding 2 is formed (as mentioned above, see Figures 7) and then from the winding station A to the cutting unit 17 (compare Figures 7 and 8), where the separator band(s) 4 is/are cut (see Figures 9 and 10).

According to alternative embodiments (such as those schematically shown in Figures 1A, 6A, 15-18), the cutting unit 17 is included in the guiding device 20, i.e. it is part of the guiding device 20. In this way, the cutting of the separator band(s) 4 takes place by means of the same guiding device 20, with obvious advantages in terms of overall dimensions and cutting precision, since there is in fact no need to synchronise the advancement speed of the guiding device 20 with that of the cutting unit 17 since they are integral. This further reduces the number of movements that are necessary to carry out the cutting of the separator band(s) 4, thus reducing either the costs (fewer motorisations and simpler programming) or the cycle time (the band(s) 4 are cut a few instants after the closing of the guiding device 20 with a latency that is difficult to replicate electrically with external systems as there would be a risk of cutting the band(s) 4 before they are perfectly gripped in the guiding device 20).

In this case, advantageously, the guiding device 20 comprises elastic means 33 arranged and configured to transfer an elastic force to the lower guiding element 21 and to the element of the upper guiding element 22, upon reaching the above-described closed position (i.e. at the moment in which said lower and upper guiding elements 21 reach the closed position) so as to induce, in use, the cutting element 18 of the cutting unit 17 to intercept and cut the separator band(s) 4 (see Figures 17 and 18).

With particular reference to Figure 21, advantageously, the cutting unit 17 is constrained (i.e., is fixed so as to be integral) to the lower guiding element 21. According to other embodiments not shown, the cutting unit 17 could be constrained (i.e., fixed so as to be integral) to the element of the upper guiding element 22.

Even in more detail (with reference to Figures 15 to 23), advantageously but not in a limiting sense, the elastic means 33 are arranged and configured so that the elastic force, which they generate upon reaching the closed position, induces a temporary (i.e. limited to a very short time interval, preferably of the order of milliseconds) approach of the lower guiding element 21 and of the upper guiding element 22 from the second distance up to a third distance, which is smaller than the second distance, so that the cutting element 18 temporarily assumes an operating position, wherein, in use, it intercepts and cuts the separator band(s) 4. In other words, the elastic force transmitted by said elastic means 33 will induce a temporary further movement of the lower guiding element 21 and of the upper guiding element 22 between them, and consequently a temporary movement of the cutting unit 17 which is constrained to one of them (i.e. to one between the lower guiding element 21 and the upper guiding element 22) up to the operating position wherein the cutting element 18 can intercept and cut the separator band(s) 4 which are retained by the guiding device 20. In detail, driven by the recovery of the elastic means 33, after the band(s) 4 are cut, the lower guiding element 21 and the upper guiding element 22 move back to the second distance between them.

In the embodiment partially shown in Figures 15 to 23, the support member 29 comprises (is constituted by) two parts 29' and 29'’ which can be operated, by a drive assembly 38 (per se known and not described in detail herein), to move reciprocally so as to induce the passage of the lower guiding element 21 and of the upper guiding element 22 from the open position to the closed position, and vice versa. In detail, according to certain embodiments, one of said parts 29' and 29'’ (e.g. the lower part 29') is fixed and the other (the upper part 29'’) is movable so as to reach the aforementioned closed position. Thus, in this case, the lower guiding element 21 is fixed and the upper guiding element 22 moves towards or away with respect to the lower guiding element 21.

It is understood that according to alternative embodiments, only the upper part 29'', hence only the upper guiding element 22 could be moved, or again both parts 29' and 29'’ of the support member 29 could move, and thus both guiding elements 21 and 22 could be movable to move closer or away to/from each other.

Furthermore, in this case (see Figures 15 to 23) the lower guiding element 21 in place of the single gripping portion 27 comprises, in addition to the aforementioned lower main body 26, two gripping portions 27 and 27' which are parallel and side-by-side with each other, advantageously but not necessarily arranged at a reciprocal distance of less than 15mm, preferably less than 10mm, extend transversely to the main body 26, and protrude from the lower main body 26 towards the upper guiding element 22. Similarly, the upper guiding element 22, in place of the single gripping portion 27', comprises, in addition to the aforementioned upper main body 26', two other gripping portions 27'’ and 22’’’ which are parallel and side-by-side with each other, extend transversely to the upper main body 26' and protrude from the upper main body 26' towards the lower guiding element 21.

In detail, as schematically shown in Figures 15, 16, 17 and 18, the gripping portions 27' and 27'’ are arranged with one another (i.e. they cooperate with each other) in order to exert, in closed position, a gripping action upon the separator band(s) 4 in order to retain it and guide it; and, in a similar manner, the gripping portions 27' and 22’’’ are arranged with one another (i.e. they cooperate with each other) in order to exert, in a closed position, the aforementioned gripping action upon the separator band(s) 4 in order to retain it and guide it.

Advantageously, but not in a limiting sense, the guiding device 20 further comprises at least one pressing element 35 which is fixed to the gripping portion 27 or to the gripping portion 27'’ so as to exert said gripping action upon the separator band(s) 4, and at least one further pressing element 35' which is fixed to the gripping portion 27' or to the gripping portion 27"'. In this way, advantageously these pressing elements 35 and 35' that will be the ones exerting the aforementioned gripping action upon the separator band(s) 4 in order to retain it and guide it.

In detail, as mentioned for the other embodiments also for those shown in Figures 1A, 6A, 14-23 and 23A, the pressing elements 35 and 35' are configured to exert a gripping action upon the separator band(s) 4 that is such as to retain it/them while it/they advance (s) up to the winding core 5 but, at the same time, which is less than the winding action transferred by the rotating elements 16 upon the separator band(s) 4 when winding, so as to allow the winding core 5 (and in particular the rotating elements 16, once placed inside the cavity 25 in winding configuration and caused to rotate) to remove the separator band(s) 4 from the gripping portions 27 and 27'’ and 27' and 22’’’ without damaging it and causing it to rotate.

Even in more detail, advantageously but not in a limiting sense, the pressing elements 35 and 35', are made of a compressible material (i.e. elastically deformable, even in more detail reversibly elastically shortenable and extendable) so that, the aforementioned elastic force transferred from the elastic means 33 to the guiding elements 21, induces a compression of said pressing elements 35 and 35' (i.e. a deformation thereof, more in detail a shortening thereof in the direction of application of the elastic force) so as to induce a temporary passage of the lower and upper guiding elements 21 and 22 from the second distance (in the closed position) to the third distance (wherein at least the cutting element 18 is in the operating position).

It is understood that according to other embodiments not shown, each of these gripping portions 27, 27', 27’’, 22’’’ comprises a pressing element.

In accordance with some embodiments (such as the one shown, for example, in Figures 20, 21, and 22), the cutting element 18 extends transversely to the advancement direction X along the lower main body 26 and is interposed between the gripping portion 27 and the gripping portion 27', advantageously in a central position (i.e. equidistant with respect to said gripping portions 27 and 27'), so that in an operating position it protrudes with respect to said gripping portions 27 and 27' in order to be able to intercept and cut the separator band(s) 4 retained, in use, by the gripping portions 27 and 27'’ and 27' and 27'"' as explained above. It is understood that according to other embodiments not shown, as mentioned above, the cutting unit 17 could be fixed to the upper guiding element 22 and the cutting element 18 could extend along the upper main body 26' between the gripping portion 27'’ and the gripping portion 27’’’, advantageously in a central position (i.e. equally spaced with respect to said gripping portions 27'’ and 2'1’’’). In this case, in the operating position, the cutting element would protrude from the gripping portions 27'’ and 2'1’’’ so as to intercept and cut the separator band(s) 4 retained, in use, by the gripping portions 27 and 2'1’’ and 27' and 27"' as explained above.

Advantageously but not in a limiting sense (as in the embodiment shown in Figure 22, the cutting element 38 comprises (in particular, it is constituted by) a knife with a multipoint blade, i.e. having a plurality of points arranged in succession along the aforementioned direction transverse to the advancement direction X.

Furthermore, advantageously but not necessarily, in order to make the cutting and the winding as precise as possible and to ensure that the separator band(s) 4 are held in position (in particular at the correct height) during the insertion of the rotating elements 16, the lower guiding element 21 comprises a protuberance 36 extending from the lower main body 26 towards the upper main body 26' and the upper guiding element 22 comprises a further protuberance 36' extending from the upper main body 26' towards said first lower main body 26. Said protuberances 36 and 36', in the closed position, are arranged counter- face-to-face and spaced apart to guide and to hold in position the separator band(s) 4 during the insertion of the rotating elements 16, thereby improving the cutting and/or the winding.

Even in more detail, advantageously but not in a limiting sense, said protuberances 36 and 36' are arranged so that in the closed position between them there is left a passage defined which is dimensioned to receive and guide the separator band(s) 4 ensuring that the correct position (i.e. the level) is held during the cutting and/or the winding. This makes it possible to avoid the risk of noninsertion of the rotating elements 16 due to misalignments that the separator band(s) 4 may present if the previous guiding element (for example, the rollers 11 the guiding means 12 of the feeding unit 7) is located beyond a certain distance (for example, allowing the separator to bulge), thus risking compromising the correct success of the cutting and/or winding operations.

In this case (i.e. when these projections 36 and 36' are present), these laterally delimit the above described cavity 25, which will then be delimited at the bottom and at the top by the above mentioned inner walls 30, 30', respectively, of the lower main body 26 and of the upper main body 26', and laterally by the protuberances 36 and 36', on one side, and by the gripping portions 27 and 27’’, on the opposite side (see, for example, Figures 16, 18, 20 and 21).

According to the advantageous but non-limiting embodiments shown in Figures 15 to 23 and 23A, the aforementioned elastic means 33 comprise two springs 37 each arranged at the bottom of, and at the ends of, the lower main body 26 and operatively coupled (i.e. connected) to said lower main body 26 for transferring the aforementioned elastic force thereon, and through it to the lower and upper guide elements 21 and 22. Even in more detail, in this case, advantageously but not in a limiting sense, the aforementioned support member 29 comprises two supports 39 which support (from below) said springs 37 which will be interposed between the supports 39 and the main body 26 for transferring the aforementioned elastic force.

In combination or alternatively, the springs 37 could be arranged at the top of, and at the ends of, the upper main body 26' and operatively coupled (i.e. connected) to said upper main body 26' for transferring the aforementioned elastic force thereon, and through it to the lower and upper guide elements 21 and 22, upon reaching the closed position.

In other words, upon reaching the closed position, the lower and upper guiding elements 21 and 22 and the respective gripping portions 27, 27', 27’’, 22’’’ come into contact with each other, and the impact induces the deformation (i.e. the shortening) of the springs 37 generating the aforementioned elastic force, which induces the cutting element 18 to assume the aforementioned operating position for an interval of time (of the order of ms).

Advantageously, see Figure 23A, such springs 37 are bauer springs also known as "disc" springs (known per se and not further described herein). The use of this particular type of spring 37 allows avoiding the risk of inclinations and oscillations of the lower and upper guiding elements 21 and 22 as a result of the transfer of the elastic force, even with only two springs 37.

It is understood that the springs 37 could be more than two, for example there could be another spring in a central position with respect to the lower main body 26. Advantageously but not necessarily, and as shown in the non-limiting embodiment of Figures 21-23, the guiding element 22 comprises a housing 40, preferably a through housing, which is configured to accommodate the cutting element 18 during the aforementioned operating position. It is understood that if the cutting element is integral with the guiding element 22, the housing 40 is formed in the guiding element 21.

According to a further aspect of the present invention, a winding method is proposed, in particular to form an electrical energy storage device.

The winding method comprises the following steps: a first feeding step, during which at least one separator band 4 is fed; a first winding step, during which the separator band 4 is engaged by a winding core 5 (advantageously of the type described above), in particular by winding for at least half a turn, even more particularly for at least 270°, the separator band 4 around the winding core 5; a second feeding step, at least partially subsequent to the first winding step, during which an electrode band 3 is fed to the winding core 5, advantageously but not limitedly by means of a feeding unit 8 of the type described above; a second winding step, during which also the electrode band 3 is wound around the winding core 5 to form a winding 2; and a first cutting step, advantageously carried out by means of the cutting unit 17 described above, during which at least the separator band 4 is cut.

Advantageously, the first feeding step is carried out by means of a feeding unit 7 like the one described above and entails feeding two separator bands 4 to the winding core 5. In detail, such separator bands 4 are fed spaced apart so as to be able to receive an electrode band 3 (typically the cathode) between them.

Furthermore, advantageously, the method entails a further feeding step, advantageously carried out by means of the feeding unit 9 described above, during which another electrode band 3 (typically the anode) is fed, and a further winding step at least partially simultaneous with the aforementioned first and second winding step, during which said further electrode band 3 is wound (together with the first electrode band 3 and with the separator bands 4) around the winding core 5. Furthermore, advantageously but not in a limiting sense, the method entails two further cutting steps which are advantageously (carried out by means of the cutting units 17' and 17'’ described above and) prior to the winding of said electrode bands 3, during which the electrode bands 3 are cut.

Advantageously, the winding method entails that during the first feeding step, the first winding step and the first cutting step the separator band(s) 4 is/are guided by the guiding device 20 described above which is movable along the advancement direction X of the separator band(s) 4.

Advantageously but not in a limiting sense, the first winding step comprises: a positioning sub-step during which the guiding device 20 in a closed position guides the separator band(s) 4 up to the winding core 5 by positioning itself so that said winding core (5) is located in the area of the cavity 25 (as explained more fully above with reference to the winding apparatus 1); and a return substep, which is subsequent to the positioning sub-step, during which the rotating elements 16 assume the winding configuration and are caused to rotate, around the rotation axis R, so as to transmit the aforementioned winding action to the separator band(s) 4. As explained above, this winding action is greater than the gripping action exerted by the guiding device 20 so that the separator band(s) 4 can be removed from the guiding device 20 and wound around the winding core 5.

Advantageously but not in a limiting sense, the first cutting step (as well as the further cutting steps) is carried out "on the fly", i.e. while the separator band(s) 4 advance (s) with a defined speed along the advancement direction X.

Even more particularly, according to the embodiment shown in Figures 1 to 14, the first cutting step entails the alignment sub-steps, prior to the operation of the cutting unit 17, during which the cutting unit 17 is moved along said advancement direction X until it reaches an advancement speed similar to the advancement speed of the separator band(s) 4. In other words, the first cutting step (as well as the further cutting steps) is carried out only when the relative speed between the cutting unit 17, and more particularly between the cutting element 18, and the separator band 3 is zero.

According to the embodiments shown in Figures 1A, 6A and 15-23, the first cutting step entails a sub-step of transferring an elastic force, during which elastic means 33, advantageously of the type described above, transfer an elastic force to the lower guiding element 21 and to the upper guiding element 22, so as to induce the abovedescribed cutting element 18 to intercept and cut the separator band(s) 4 retained by said guiding device 20 (advantageously of the type described above, with reference to the embodiments shown in Figures 1A, 6A and 15-23). According to some embodiments, the first cutting step is subsequent to the first winding step (see, for example, Figures 4 and 5 wherein the already formed winding 2 has been transferred to the closing station B, or Figures 9 and 10 wherein a winding 2 is already present in the winding station A while the cutting takes place).

Furthermore, advantageously but not limitedly, the method entails a return step, subsequent to the first cutting step, during which a first flap 34 of the cut separator band(s) 4 is caused to return by the winding core 5, which may have passed in the above-described closing station B (compare between them Figure 4 showing the flap 34 that is about to be cut and Figure 5 wherein said flap 34 has been caused to return so as to form the last layers in the winding 2), or may be in the winding station A (compare between them Figure 9 showing the flap 34 that is about to be cut and Figure 10 wherein said flap 34 has been caused to return so as to form the last layers in the winding 2).

According to alternative embodiments not shown, the first cutting step may prior to the first winding step. In this case, advantageously but not in a limiting sense, the separator band(s) 4 are cut before being fed, by guiding them with the above-described guiding device 20, towards the winding core 5.

According to a further aspect of the present invention, there is provided a guiding and cutting system comprising the cutting unit 17 and the guiding device 20 according to what has been described so far.

The winding method and apparatus 1 of the present invention have numerous advantages, among which the following ones are mentioned. The winding method and apparatus 1 described above allow, thanks to the presence of the guiding device 20 described above, to optimise the formation of the winding 2 and in particular to optimise the use of the separator band 4, avoiding, with respect to the prior arts, turns of the separator band 4 being made idly, i.e. due to operation requirements of the winding method and/or apparatus 1 (and not for their actual need in the winding 2, and more particularly in the electrical energy storage device). In doing so, the winding method and apparatus 1 described above also allow a reduction in winding times compared to known winding methods and apparatuses.

Furthermore, the winding method and apparatus 1 of the present invention allow obtaining a more compact winding 2 than that obtained with the known methods and apparatuses with the same energy capacity.

Furthermore, when the cutting unit 17 is included in the guiding device 20, the winding method and apparatus 1 of the present invention allow a reduction in the overall dimensions and a more rapid and precise execution of the cutting of the separator band(s) 4 that is/are cut while being retained under tension by the aforementioned gripping portions 27, 27'' and 27' and 27'''.