Cylindrical electrochemical cell manufacturing apparatus and manufacturing method thereof

Abstract

The present invention relates to an apparatus (9) and a method for manufacturing a cylindrical electrochemical cell (2) comprising a spiral winding of a composite material (8) comprising at least two overlapping conductor bands (4, 6) and at least two separator bands (5, 7). The apparatus comprises a number of winding heads (13) each supporting a holding device (14) configured to grip one end of the composite material (8). The holding device (14) is configured to rotate about its first axis of rotation (15) so as to obtain a spiral winding of the composite material (8). The apparatus also comprises a drum (11) supporting the winding head (13). The drum (11) is rotatably mounted to rotate about a second axis of rotation (12) according to a continuous law of motion in order to move the winding head (13) along a processing path (P2). The apparatus also comprises a supply unit (10) configured to supply the composite material (8) to the winding head (13).

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for manufacturing an electrochemical cell.

[0002] The present invention is advantageously applied to the production of cylindrical lithium-ion batteries, to which reference is made explicitly in the following description, without loss of generality. [Background technology]

[0003] Commercially available lithium-ion batteries are assembled in three different configurations: cylindrical, prismatic and pouch.

[0004] A cylindrical battery contains a single electrochemical cell, consisting of an anode, separator, and cathode wound together, housed within a cylindrical metal container.

[0005] In particular, the cylindrical container is initially open on one side (i.e., cup-like with a closed bottom end and an open top end) to allow for the introduction of the wound electrochemical cell and an electrolyte that will impregnate the wound electrochemical cell. Once the battery is formed (i.e., all components are disposed within the cylindrical container), the open end of the cylindrical container is closed to form a hermetic closure.

[0006] To form a cylindrical electrochemical cell, the composite material (including at least two overlapping conductor bands and at least two separators) must be fed to a winding head provided with a holding device, where the holding device is configured to rotate about a central axis of rotation so as to grip one end of the composite material and obtain a spiral winding of the composite material.

[0007] The known manufacturing apparatus comprises a vertically arranged drum supporting a number of winding heads. The drum is rotatably mounted to rotate about a horizontal axis of rotation in order to move the winding heads along a complete circular processing path. The known manufacturing apparatus also comprises a feeding unit configured to feed the composite material to the winding heads. In particular, in the known manufacturing apparatus, the drum rotates about its own axis of rotation with an intermittent (stepwise) motion law that includes periodically alternating motion steps in which the drum rotates and stationary steps in which the drum remains stationary.

[0008] It has been observed that known manufacturing equipment cannot achieve high production rates (measured as cylindrical electrochemical cells produced per unit time) without compromising the quality of the final product. To ensure high quality of the final product, known manufacturing equipment necessarily needs to be operated at a limited production rate (approximately 15-20 cylindrical electrochemical cells produced per minute). Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide an apparatus and method for manufacturing electrochemical cells that allows to operate at high production rates (measured as cylindrical electrochemical cells produced per unit time) while ensuring high quality of the final product. [Means for solving the problem]

[0010] Thus, in a first aspect thereof, the present invention relates to an apparatus for manufacturing a cylindrical electrochemical cell comprising a spiral winding of a composite material comprising at least two conductor bands and at least two separator bands, preferably overlapping each other.

[0011] Preferably, the manufacturing apparatus includes a plurality of winding heads.

[0012] Preferably, each of the winding heads supports a holding device configured to grip one end of the composite material.

[0013] Preferably, the holding device is configured to form a helical winding of the composite material.

[0014] Preferably, the holding device is configured to rotate about its own first axis of rotation to form a helical winding of the composite material.

[0015] Preferably, the manufacturing apparatus includes a drum supporting a winding head.

[0016] Preferably, the head is rotatably mounted for rotation about a second axis of rotation to move the winding head along the process path.

[0017] Preferably, the manufacturing apparatus comprises a supply unit configured to supply the composite material to the winding head.

[0018] Preferably, the drum rotates about the second axis of rotation according to a continuous law of motion.

[0019] In a second aspect, the present invention relates to a method for producing a preferably cylindrical electrochemical cell comprising a spiral winding of a composite material, preferably comprising at least two conductor bands and at least two separator bands overlapping each other.

[0020] Preferably, the method includes rotating a holding device configured to grip one end of the composite material about its first axis of rotation so as to obtain a spiral winding of the composite material.

[0021] Preferably, the holding device is supported by the winding head.

[0022] Preferably, the method includes moving a plurality of winding heads along the process path.

[0023] Preferably, the step of moving the plurality of winding heads is performed by a drum supporting the winding heads and rotatably mounted for rotation about the second axis of rotation.

[0024] Preferably, the method includes the step of feeding the composite material to a winding head by a feeding unit.

[0025] Preferably, the drum rotates about the second axis of rotation according to a continuous law of motion.

[0026] The present invention, in at least one of the above-mentioned aspects, may have at least one of the further preferred features described below.

[0027] Preferably, the feed unit is configured to move the composite material at a substantially constant moving speed.

[0028] Preferably, the supply unit is configured to move the material without interrupting the movement of the composite material.

[0029] Preferably, the feed unit is configured to move the composite material at a substantially constant moving speed and thus without interruption of the movement of the composite material.

[0030] Preferably, the feed unit is configured to move the composite material along a linear feed path.

[0031] Preferably, the linear feed path is arranged vertically.

[0032] Preferably, the feeding unit is configured to move the composite material from top to bottom.

[0033] Preferably, the processing path segments are substantially straight and parallel to the feed path.

[0034] Preferably, the processing path segments are substantially straight.

[0035] Preferably, each of the holding devices is configured to grip one end of the composite material.

[0036] Preferably, each of the holding devices is configured to initiate spiral winding of the composite material while the corresponding winding head is moved along a substantially linear segment of the processing path.

[0037] Preferably, each of the holding devices is configured to grip one end of the composite material to initiate spiral winding of the composite material while the corresponding winding head is moved along a substantially linear segment of the processing path.

[0038] Preferably, the manufacturing apparatus comprises a first cutting device configured to cut the composite material.

[0039] Preferably, the first cutting device is configured to cut a composite material.

[0040] Preferably, the first cutting device is configured to form a new free end of the composite material while the composite material is still being wound by the first winding head.

[0041] Preferably, the first cutting device is configured to cut the composite material to form a new free end of the composite material while the composite material is still being wound by the first winding head.

[0042] Preferably, the manufacturing apparatus includes a second winding head following the first winding head along the process path.

[0043] Preferably, the second head is configured to grip a new free end of the composite material while the first winding head completes winding of its own composite material.

[0044] Preferably, a second winding head following the first winding head along the processing path is configured to grip a new free end of the composite material and begin winding the composite material while the first winding head has completed winding its own piece of the composite material.

[0045] Preferably, the drum is configured to position the first winding head and the second winding head at a minimum mutual distance along the processing path at the moment the first cutting device cuts the composite material.

[0046] Preferably, the feed unit comprises two opposing compression rollers between which the composite material passes.

[0047] Preferably, the first cutting device is arranged downstream of the two compression rollers.

[0048] Preferably, the first cutting device is movably mounted to move forward or backward along a segment of the feed path.

[0049] Preferably, the manufacturing apparatus comprises an actuation device configured to cause the first cutting device to cyclically perform a forward stroke in which the first cutting device synchronously follows the winding head along a segment of the processing path and a return stroke in which the first cutting device returns to the starting position to synchronously follow the subsequent winding head.

[0050] Preferably, the first cutting device is configured to cut the composite material at the end of the forward stroke.

[0051] Preferably, the holding device of each winding head is configured to grip one end of the composite material.

[0052] Preferably, the holding device of each winding head is configured to begin forming the spiral winding immediately after the first cutting device cuts the composite material.

[0053] Preferably, the holding device of each winding head is configured to grip one end of the composite material and begin forming the spiral winding immediately after the first cutting device cuts the composite material.

[0054] Preferably, the holding device of the winding head located closest to the first cutting device is configured to start forming the spiral winding immediately after the first cutting device has cut the composite material.

[0055] Preferably, the holding device of the winding head located closest to the first cutting device is configured to grip one end of the composite material and begin forming the spiral winding immediately after the first cutting device cuts the composite material.

[0056] Preferably, when the composite material is cut by the first cutting device, the winding head arranged closest to the first cutting device is located upstream of the first cutting device with respect to the moving direction of the composite material.

[0057] Preferably, the first cutting device comprises a first sideboard having a face parallel to the feed path followed by the composite material.

[0058] Preferably, the first cutting device comprises a blade slidably mounted relative to the second sideboard.

[0059] Preferably, each of the winding heads comprises a second sideboard arranged opposite the first sideboard along the segment of the processing path and defining, together with the first sideboard, a channel in which the composite material is disposed.

[0060] Preferably, each of the winding heads comprises a third sideboard arranged adjacent the holding device opposite the second sideboard.

[0061] Preferably, the supply unit comprises two second cutting devices each configured to cut only a corresponding conductor band.

[0062] Preferably, the feed unit comprises two opposing compression rollers between which the composite material passes.

[0063] Preferably, each of the second cutting devices is arranged upstream of the two compression rollers.

[0064] Preferably, each of the winding heads is rotatably mounted to the drum for rotation relative to the drum itself about a third axis of rotation, preferably parallel to the second axis of rotation.

[0065] Preferably, each of the winding heads is rotatably mounted to the drum for rotation relative to the drum itself about a third axis of rotation, preferably parallel to the second axis of rotation.

[0066] Preferably, each of the winding heads is rotatably mounted to the drum for rotation relative to the drum itself about a fourth axis of rotation, preferably parallel to the second axis of rotation.

[0067] Preferably, each of the winding heads is hinged to the end of the first arm so as to rotate relative to the first arm.

[0068] Preferably, each of the winding heads is hinged to an end of the first arm for rotation relative to the first arm about a fifth axis of rotation.

[0069] Preferably, the end of the first arm opposite the winding head is hinged to the end of the second arm for rotation relative to the second arm about a fourth axis of rotation.

[0070] Preferably, an end of the second arm opposite the first arm is hinged to the drum for rotation relative to the drum about a third axis of rotation.

[0071] Preferably, the feed unit is movably mounted to move forward or backward along a segment of the processing path.

[0072] Preferably, the supply unit is rotatably mounted, preferably for rotation about the second axis of rotation.

[0073] Preferably, the manufacturing apparatus comprises an actuation device configured to cause the supply unit to cyclically perform a forward stroke in which the supply unit synchronously follows the winding head along a segment of the processing path, and a return stroke in which the supply unit returns to the starting position to synchronously follow the subsequent winding head.

[0074] The appended claims set forth embodiments of the invention which form an integral part of this disclosure. [Brief description of the drawings]

[0075] The invention will now be described with reference to the accompanying drawings, which show non-limiting embodiments thereof. [Figure 1] FIG. 1 is a schematic diagram of a cylindrical battery. [Diagram 2] FIG. 2 is a schematic diagram of a cylindrical electrochemical cell of the cylindrical battery of FIG. 1. [Diagram 3] FIG. 2 is a schematic front view of a manufacturing apparatus for manufacturing the cylindrical electrochemical cell of FIG. [Figure 4] 4 is a schematic front view of a supply unit of the manufacturing apparatus of FIG. 3. [Diagram 5] 4 is a schematic front view of the drum of the manufacturing apparatus of FIG. 3 during operation. FIG. [Figure 6] 6 is a schematic front view of the drum of the manufacturing apparatus of FIG. 3 during an operation different from that in FIG. 5. [Figure 7] 7 is a schematic front view of the drum of the manufacturing apparatus of FIG. 3 during an operation different from that in FIG. 5 and FIG. 6. [Figure 8] 8 is a schematic front view of the drum of the manufacturing apparatus of FIG. 3 during an operation different from that in FIGS. 5 to 7. FIG. [Figure 9] FIG. 9 is a schematic perspective view of a modified example of the drum of FIGS. 5 to 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0076] In FIG. 1 a cylindrical power battery is generally designated by the reference number 1.

[0077] The cylindrical battery 1 includes a "jelly roll" or "Swiss roll" electrochemical cell 2 in which multiple sheets are rolled into a cylindrical shape, and a cylindrical container 3 that houses the electrochemical cell 2.

[0078] 2, the cylindrical electrochemical cell 2 is composed of a spiral winding of a set of four bands including a conductor band 4 made of a metallic material (typically aluminum) constituting the cathode, a separator band 5 made of a porous material (later immersed in a liquid electrolyte), a conductor band 6 made of a metallic material (typically copper) constituting the anode, and a separator band 7 made of a porous material (later immersed in a liquid electrolyte). In other words, the four overlapping bands 4-7 form a composite material 8 (i.e., a "sandwich" of the four bands 4-7), which is spirally wound on itself to form the cylindrical electrochemical cell 2.

[0079] According to a preferred embodiment, in the initial and final sections (i.e. the small segment at the head and the small segment at the rear end) the composite material 8 is only formed by two overlapping separator bands 5 and 7. In other words, the composite material 8 is not uniform along its entire length, since in the initial and final sections the composite material 8 is only formed by two overlapping separator bands 5 and 7, whereas in the (large) central section the composite material 8 is only formed by the overlapping four bands 4-7. This allows to increase the electrical insulation at the beginning and end of the cylindrical electrochemical cell 2 and to reduce the risk of undesired short circuits.

[0080] In FIG. 3, a manufacturing apparatus for producing cylindrical electrochemical cells 2 is indicated generally by the reference numeral 9 .

[0081] The manufacturing apparatus 9 comprises a feeding unit 10 configured to feed the composite material 8 (formed by the overlapping bands 4-7) along a vertically oriented, linear feeding path P1. Preferably, the feeding unit 10 is configured to move the composite material 8 from top to bottom in order to take advantage of gravity (i.e., gravity tends to push the composite material 8 along the feeding path P1 without causing the composite material 8 to deviate from the feeding path P1).

[0082] In particular, the supply unit 10 is configured to move the composite material 8 along the supply path P1 always at a constant moving speed, without interrupting the movement of the composite material 8. In other words, the composite material 8 leaves the supply unit 10 according to a continuous law of motion, i.e. according to a law of motion that provides a movement without stopping at a constant moving speed (which naturally increases or decreases according to the increase or decrease of the output per hour at which the manufacturing device 9 operates). That is to say, the composite material 8 leaving the supply unit 10 is always moved at an equal speed, without cyclically alternating between stationary and moving steps.

[0083] The manufacturing device 9 comprises a drum 11 (vertically oriented) mounted for rotation about a horizontal axis of rotation 12 (perpendicular to the sheet plane). The drum 11 supports a number of winding heads 13. The drum 11 rotates about the axis of rotation 12 according to a continuous law of motion, i.e. according to a law of motion that provides a movement without stopping at a constant speed of movement (which naturally increases or decreases according to the increase or decrease in the power per unit time at which the manufacturing device 9 operates). That is to say, the drum 11 does not periodically alternate between rest and movement steps, but always rotates about the axis of rotation 12 with the same angular velocity.

[0084] Rotation of the drum 11 about its axis of rotation 12 causes each of the winding heads 13 to move along a similarly shaped processing path P2. The segments of the processing path P2 are substantially straight and parallel to (and therefore substantially perpendicular to) the feed path P1, i.e. the straight segments of the processing path P2 substantially coincide with the corresponding segments of the feed path P1.

[0085] Each of the winding heads 13 comprises a holding device 14 configured to grip one end of the composite material 8. The holding device 14 is configured to rotate on itself about an axis of rotation 15 (horizontal and parallel to the axis of rotation 12) so as to obtain a spiral winding of the composite material 8 (i.e. so as to obtain a corresponding cylindrical electrochemical cell 2). Preferably, each of the winding heads 13 supports an electric motor which effects the rotation of the holding device 14 about the axis of rotation 15.

[0086] According to a preferred embodiment, and as described in more detail below, each of the holding devices 14 is configured to grip one end of the composite material 8 and begin winding the composite material 8 while the corresponding winding head 13 moves along a substantially linear segment of the processing path P2.

[0087] As shown in more detail in FIG. 4, the feeding unit 10 comprises four unwinding devices 16 which unwind the composite material 8 from corresponding coils (not shown) and move the composite material 8 to two compression rollers 17. The two compression rollers 17 press the composite material 8 between them to obtain an optimal overlap of the composite material 8. Each of the unwinding devices 16 comprises a tension member which applies and maintains the corresponding composite material 8 (formed by the overlapping bands 4-7) at a constant tension equal to a desired value. The feeding unit 10 comprises two cutting devices 18, each of which is configured to cut only the corresponding conductor band 4 or 6 and is arranged upstream of the two compression rollers 17. That is, each of the cutting devices 18 is operable to cut only the corresponding conductor band 4 or 6 before the conductor band 4 or 6 reaches the two compression rollers 17.

[0088] As shown in more detail in figure 3, the feed unit 10 comprises a fixed guide 19 (not shown in the following figures for clarity) arranged downstream of the compression roller 17 with respect to the direction of movement of the composite material 8. The fixed guide 19 serves to guide the movement of the composite material 8 along the feed path P1.

[0089] As shown in Figures 5 to 9, each of the winding heads 13 is rotatably attached (hinged) to an end of the arm 20 so as to rotate relative to the arm 20 about a rotation axis 21 parallel to the rotation axis 12. In each of the winding heads 13, the rotation axis 21 is parallel to the rotation axis 15 of the corresponding holding device 14 and may be coaxial with the rotation axis 15 or may be (slightly) spaced from the rotation axis 15. Each of the arms 20 has an end supporting the corresponding winding head 13 and an opposite end rotatably attached (hinged) to an end of the arm 22 so as to rotate relative to the arm 22 about a rotation axis 23 parallel to the rotation axis 12. Each of the arms 22 has an end supporting the arm 20 and an opposite end rotatably attached (hinged) to the drum 11 so as to rotate relative to the drum 11 about a rotation axis 24 parallel to the rotation axis 12.

[0090] The drum 11 is provided with an actuation system 25 (shown diagrammatically in FIG. 7) which controls the position of the winding head 13 relative to the drum 11, i.e. the rotation about the axes of rotation 21, 23 and 24. Preferably, the actuation system 25 uses a fixed cam located within the drum 11 which generates the movement by utilizing the rotation of the drum 11 about the axis of rotation 12.

[0091] Each of the winding heads 13 comprises a holding device 14 and a sideboard 26 and a sideboard 27 arranged on either side of the holding device 14. In particular, the sideboard 26 is arranged downstream with respect to the direction of movement along the processing path P2, and the sideboard 27 is arranged upstream with respect to the direction of movement along the processing path P2. The sideboards 26 and 27 are designed to help guide the movement of the composite material 8 along the feed path P1, and therefore have a flat surface that, in use, faces the feed path P1.

[0092] The manufacturing apparatus 9 comprises a cutting device 28 configured to cut the composite material 8. The cutting device 28 is mounted so as to be movable forwards or backwards along a segment of the feed path P1. The cutting device 28 is therefore arranged downstream of the two compression rollers 17 of the feed unit 10.

[0093] The cutting device 28 comprises a sideboard 29 designed to help guide the movement of the composite material 8 along the feed path P1. The sideboard 29 has a surface parallel to the feed path P1. The cutting device 28 also comprises a blade 30 slidably mounted relative to the sideboard 29. As will be explained in more detail below, in use, the sideboard 29 of the cutting device 28 is arranged opposite the sideboard 26 of the corresponding winding head 13 along a substantially straight segment of the processing path P2 (which is parallel to the feed path P1) and defines, together with the sideboard 26, a channel in which the composite material 8 is placed.

[0094] The cutting device 28 is provided with an actuation device 31 (typically provided with its own independent electric motor) configured to cause the cutting device 28 to cyclically perform a forward stroke in which the cutting device 28 synchronously follows the winding head 13 along a substantially straight segment of the processing path P2 (parallel to the supply path P1) and a return stroke in which the cutting device 28 returns to the starting position in order to synchronously follow the subsequent winding head 13.

[0095] Hereinafter, with reference to Figures 5 to 8, a method for manufacturing a cylindrical electrochemical cell 2 by winding a strip-shaped composite material 8 around a winding head 13 (shown in the upper left of Figure 5) will be described, and the operation of the manufacturing apparatus 9 will be described.

[0096] According to Fig. 5, first the previous winding head 13 (i.e., located downstream of the new winding head 13 along the processing path P2 and shown in the bottom left of Fig. 5) winds up the strip of composite material 8 by rotating its own holding device 14 on itself. In this state, the new winding head 13 (shown in the top left of Fig. 5), which is not winding and does not have the composite material 8 engaged with its own holding device 14, arrives at the beginning of a substantially straight (and vertical) segment of the processing path P2.

[0097] When a new winding head 13 (shown in the top left of FIG. 5 ), which is not winding and is not engaged with a composite material 8, arrives at the beginning of a substantially straight (and vertical) segment of the processing path P2, the winding head 13 encounters (at the beginning of its forward stroke) a cutting device 28 arranged opposite the winding head 13. At this time, i.e. at the beginning of the substantially straight segment of the processing path P2, a sideboard 29 of the cutting device 28 is arranged opposite the sideboard 26 of the winding head 13 and defines, together with the sideboard 26, a channel in which the composite material 8 is arranged, i.e. the two sideboards 26 and 29 accommodate the composite material 8 between them.

[0098] At this point, as shown in FIG. 6, the winding head 13 (shown in the upper left of FIG. 6), which is not winding and is not engaged with the composite material 8, continues to move along a substantially straight (and vertical) segment of the processing path P2 (which is parallel to the feed path P1), while the cutting device 28 completes a forward stroke in which the cutting device 28 synchronously follows the winding head 13 (i.e., remains facing the winding head 13).

[0099] As shown in Fig. 7, at the end of the substantially straight (and vertical) segment of the processing path P2, the winding head 13 (shown in the upper left of Fig. 7), which is not winding and is not engaged with the composite material 8, prepares to start winding itself. Now, the cutting device 28 cuts the composite material 8 and forms a new free end of the composite material 8, while the forward winding head 13 (shown in the lower left of Fig. 7) continues winding the composite material 8. The rear end of the composite material 8 downstream of the cut is wound by the forward winding head 13 (shown in the lower left of Fig. 7), while the head of the composite material 8 upstream of the cut (i.e. the new free end of the composite material 8 formed by the cut) is engaged by the holding device 14 of the winding head 13 facing the cutting device 28 (shown in the upper left of Fig. 7).

[0100] In other words, the cutting device 28 is configured to cut the composite material 8 to form a new free end of the composite material 8 while the composite material 8 is still being wound by the previous winding head 13 (shown in the lower left of Figure 7), and the subsequent winding head 13 (shown in the upper left of Figure 7) following the previous winding head 13 along the processing path P2 is configured to grip the new free end of the composite material 8 and begin winding the composite material 8 while the previous winding head 13 is still completing winding of its own composite material 8.

[0101] According to a preferred embodiment, the drum 11 is configured to position the previous winding head 13 (shown in the bottom left of FIG. 7) and the next winding head 13 (shown in the top left of FIG. 7) at a minimum mutual distance along the processing path P2 at the moment when the cutting device 28 cuts the composite material 8. In this way, the rear end of the composite material 8 spirally wound by the previous winding head 13 (shown in the bottom left of FIG. 7), downstream of the cut, is short and is not positioned in an undesirable, potentially damaging position if its position is not controlled, i.e. even if it is left for a short time.

[0102] As shown in FIG. 8, the forward winding head 13 (shown in the lower left of FIG. 8) then leaves the substantially straight (and vertical) segment of the processing path P2, and the cutting device 28 begins its return stroke leaving the winding head 13 (shown in the upper left of FIG. 8) that is at the end of its forward stroke and has just started winding its own composite material 8, and then approaches the new winding head 13 (shown in the upper right of FIG. 8) which begins to cover the substantially straight (and vertical) segment of the processing path P2.

[0103] As mentioned above, the actuation device 31 is configured to cause the cutting device 28 to periodically perform a forward stroke, during which the cutting device 28 synchronously follows the winding head 13 along a substantially straight segment of the processing path P2 (parallel to the feed path P1), and a return stroke, during which the cutting device 28 returns to the starting position to synchronously follow the subsequent winding head 13. Preferably, the cutting device 28 is configured to cut the composite material 8 at the end of the forward stroke.

[0104] Additionally, as described above, the holding device 14 of each winding head 13 is configured to grip one end of the composite material 8 and begin forming a spiral winding immediately after the cutting device 28 cuts the composite material 8. In particular, the holding device 14 of the winding head 13 located closest to the cutting device 28 grips one end of the composite material 8 and begins forming a spiral winding immediately after the cutting device 28 cuts the composite material 8.

[0105] According to a preferred embodiment, when the composite material 8 is cut by the cutting device 28 , the winding head 13 arranged closest to the cutting device 28 is located upstream of the cutting device 28 with respect to the direction of movement of the composite material 8 .

[0106] As mentioned above, the feed path P1 followed by the composite material 8 is straight and (preferably) vertical, while the segment of the process path P2 followed by each of the winding heads 13 is substantially straight and parallel to the feed path P1. In fact, the segment of the process path P2 followed by each of the winding heads 13 is perfectly straight and parallel to the feed path P1 followed by the composite material 8 up to the point where the winding head 13 starts winding, while from that point onwards the process path P2 followed by the winding head 13 needs to deviate slightly (i.e. not substantially) from the feed path P1 to take into account the (gradually increasing) thickness of the winding of composite material 8 (i.e. the winding head 13 needs to deviate slightly from the feed path P1 as the winding thickness increases in order to keep the winding start point on the feed path P1).

[0107] From another perspective, it can be said that the (perfectly) linear segment of the processing path P2 followed by each of the winding heads 13, which is (perfectly) parallel to the feed path P1, ends at the point where the winding head 13 starts winding, because from this point onwards it must gradually (if not substantially) move away from the feed path P1 followed by the composite material 8 in order to compensate for the (gradually increasing) increase in thickness of the winding of the composite material 8.

[0108] As mentioned above, preferably in the initial and final parts (i.e. a small segment at the head and a small segment at the rear end) the composite material 8 is formed only by two overlapping separator bands 5 and 7. This allows to increase the electrical insulation at the beginning and end of the cylindrical electrochemical cell 2. To achieve such a result, the cutting device 18 periodically cuts the corresponding conductor bands 4 and 6 in relation to the separator bands 5 and 7, stopping for a short time, while the separator bands 5 and 7 continue to move to form a (small) area along the composite material 8 without the conductor bands 4 and 6 (i.e. having only the separator bands 5 and 7), located between the end of a particular winding and the beginning of the next winding.

[0109] In a preferred embodiment shown in the accompanying drawings, the supply unit 10 is fixed and only the cutting device 28 is movably mounted to move along the segment of the processing path P2 followed by the winding head 13. According to another embodiment, not shown, the entire supply unit 10 is movably mounted to move forwards or backwards along the segment of the processing path P2 followed by the winding head 13. In this embodiment, the processing path P2 has a linear segment, so that the supply unit 10 moves forwards or backwards linearly, or the processing path P2 does not have a linear segment, so that the supply unit 10 is rotatably mounted to rotate about the rotation axis 12 about which the drum 11 also rotates. In other words, an actuation device is provided that is configured to cause the supply unit 10 to periodically perform a forward stroke, in which the supply unit 10 synchronously follows the winding head 13 along the segment of the processing path P2, and a return stroke, in which the supply unit 10 returns to the starting position in order to synchronously follow the subsequent winding head 13.

[0110] FIG. 9 shows a variant of the drum 11 which differs from the drum 11 shown in FIGS. 3 to 8 in terms of the movement mechanism that connects the winding heads 13 to the drum 11. Each of the winding heads 13 always has three degrees of freedom with respect to the drum 11, but in the embodiment shown in FIGS. 3 to 9 these three degrees of freedom are obtained by three different rotations (rotations about the rotation axes 21, 23, 24), whereas in the embodiment shown in FIG. 9 these three degrees of freedom are obtained by two different rotations (rotations about the rotation axes 21 and 24) with linear movements (i.e. the two arms 20 and 22 are not hinged to each other but are telescopically connected to translate linearly to each other).

[0111] The embodiments described herein can be combined with each other without departing from the scope of protection of the present invention.

[0112] The manufacturing apparatus 9 described above has several advantages.

[0113] First, the above-described manufacturing apparatus 9 allows for operation at a high production rate (measured as cylindrical electrochemical cells 2 produced per unit time) while ensuring high quality of the final product. In particular, the above-described manufacturing apparatus 9 is capable of producing a minimum of 30-40 cylindrical electrochemical cells per minute while ensuring high quality of the final product.

[0114] This result is obtained thanks to the possibility of optimally (i.e. with very high precision) controlling the tension of the composite material 8. The tension of the composite material 8 is always constant and equal to the desired value in all winding production steps. The winding is therefore performed perfectly even when operating at high production speeds. In other words, it has been observed that even slight variations in the tension of the composite material 8 have a negative effect on the winding quality, especially when the winding is performed at high speeds, and with the above-mentioned production device 9 it is possible to keep the tension of the composite material 8 absolutely constant.

[0115] In the above-mentioned manufacturing apparatus 9, it is possible to always keep the tension of the composite material 8 perfectly constant, mainly because the feeding unit 10 is configured to always move the composite material 8 at a constant moving speed, and therefore the movement of the composite material 8 is never interrupted. In fact, if the moving speed of the composite material 8 does not change, it is much easier to precisely control the tension of the composite material 8, and as a result, the tension of the composite material 8 can be kept constant. The fact that the drum 11 rotates about the rotation axis 12 according to a continuous law of motion contributes greatly to keeping the moving speed of the composite material 8 constant at all times.

[0116] The manufacturing device 9 described above is particularly compact and offers optimal accessibility to all components for adjustments, configuration changes, maintenance and repair work.

[0117] The manufacturing apparatus 9 described above allows the type of cylindrical electrochemical cell 2 to be changed relatively easily and quickly.

[0118] Finally, the manufacturing apparatus 9 described above is simple in construction and cost-effective. [Explanation of symbols]

[0119] 1: Cylindrical battery 2: Electrochemical cell 3: Cylindrical container 4: Conductor band 5: Separator band 6: Conductor band 7: Separator band 8: Composite material 9: Manufacturing equipment 10: Supply unit 11: Drums 12: Rotation axis 13: Winding head 14: Holding device 15: Rotation axis 16: Rewind device 17: Compression roller 18: Disconnecting device 19: Fixed guide 20: Arm 21: Rotation axis 22: Arm 23: Rotation axis 24: Rotation axis 25: Operating system 26: Sideboard 27: Sideboard 28: Disconnecting device 29: Sideboard 30: Blade 31: Actuation device P1: Supply route P2: Processing Pathway

Claims

1. A manufacturing apparatus (9) for manufacturing a cylindrical electrochemical cell (2) comprising a spiral winding of a composite material (8) comprising at least two overlapping conductor bands (4, 6) and at least two separator bands (5, 7), comprising: a plurality of winding heads (13) each supporting a holding device (14) configured to grip one end of said composite material (8), said holding device (14) configured to rotate about its first axis of rotation (15) so as to obtain a helical winding of said composite material (8); a drum (11) supporting said winding head (13), said drum (11) being mounted for rotation about a second axis of rotation (12) for moving said winding head (13) along a processing path (P2); a supply unit (10) configured to supply said composite material (8) to said winding head (13); Equipped with characterised in that the drum (11) rotates about the second axis of rotation (12) according to a continuous law of motion, Manufacturing equipment.

2. 2. The manufacturing apparatus according to claim 1, wherein the feed unit (10) is configured to move the composite material (8) at a substantially constant moving speed.

3. 2. The manufacturing device according to claim 1, wherein the supply unit (10) is configured to move the composite material (8) without interrupting the movement of the composite material (8).

4. The manufacturing apparatus according to any one of claims 1 to 3, wherein the supply unit (10) is configured to move the composite material (8) along a linear supply path (P1).

5. 5. The manufacturing device according to claim 4, wherein the linear supply path (P1) is arranged vertically and the supply unit (10) is configured to move the composite material (8) from top to bottom.

6. 6. A manufacturing apparatus according to claim 4 or 5, wherein the segments of the processing path (P2) are substantially straight and parallel to the supply path (P1).

7. the segments of the processing path (P2) are substantially linear; each of the holding devices (14) is configured to grip one end of the composite material (8) and initiate spiral winding of the composite material (8) while the corresponding winding head (13) moves along the substantially linear segment of the processing path (P2); The manufacturing apparatus according to any one of claims 1 to 6.

8. The manufacturing apparatus according to any one of the preceding claims, comprising a first cutting device (28) configured to cut the composite material (8).

9. the first cutting device (28) is configured to cut the composite material (8) to form a new free end of the composite material (8) while the composite material (8) is still being wound by the first winding head (13); a second winding head (13) following the first winding head (13) along the processing path (P2) is configured to grip a new free end of the composite material (8) and start winding the composite material (8) while the first winding head (13) is still completing its own winding of the composite material (8); The manufacturing apparatus according to claim 8.

10. 10. The manufacturing apparatus according to claim 9, wherein the drum (11) is configured to position the first winding head (13) and the second winding head (13) at a minimum mutual distance along the processing path (P2) at the moment when the first cutting device (28) cuts the composite material (8).

11. The feed unit (10) comprises two opposing compression rollers (17) between which the composite material (8) passes; said first cutting device (28) is arranged downstream of the two compression rollers (17); The manufacturing apparatus according to claim 8, 9 or 10.

12. A manufacturing apparatus as claimed in any one of claims 8 to 11, wherein the first cutting device (28) is movably mounted to move forward or backward along a segment of the feed path (P1).

13. 13. The manufacturing apparatus according to claim 12, further comprising an actuation device (31) configured to cause the first cutting device (28) to periodically perform a forward stroke, in which the first cutting device (28) synchronously follows a winding head (13) along a segment of the processing path (P2), and a return stroke, in which the first cutting device (28) returns to a starting position in order to synchronously follow a subsequent winding head (13).

14. 14. The manufacturing apparatus according to claim 13, wherein the first cutting device (28) is configured to cut the composite material (8) at an end of the forward stroke.

15. 15. The manufacturing apparatus according to claim 13 or 14, wherein the holding device (14) of the winding head (13) is configured to grip one end of the composite material (8) and begin forming a spiral winding immediately after the first cutting device (28) cuts the composite material (8).

16. 16. The manufacturing apparatus of claim 13, 14 or 15, wherein the holding device (14) of the winding head (13) located closest to the first cutting device (28) is configured to grip one end of the composite material (8) and begin forming a spiral winding immediately after the first cutting device (28) cuts the composite material (8).

17. A manufacturing apparatus as described in any one of claims 13 to 16, wherein when the composite material (8) is cut by the first cutting device (28), the winding head (13) arranged closest to the first cutting device (28) is located upstream of the first cutting device (28) in the moving direction of the composite material (8).

18. The first cutting device (28) comprises: a first sideboard (29) having a surface parallel to the feed path (P1) followed by said composite material (8); a blade (30) slidably attached to the second sideboard (26); Equipped with The manufacturing apparatus according to any one of claims 8 to 17.

19. 19. The manufacturing device according to claim 18, wherein each of the winding heads (13) comprises a second sideboard (26) arranged opposite the first sideboard (29) along a segment of the processing path (P2) and defining, together with the first sideboard (29), a channel in which the composite material (8) is placed.

20. 20. The manufacturing apparatus according to claim 19, wherein each of the winding heads (13) comprises a third sideboard (27) arranged adjacent to the holding device (14) on the opposite side to the second sideboard (26).

21. The manufacturing apparatus according to any one of the preceding claims, wherein the supply unit (10) comprises two second cutting devices (18) each configured to cut only the corresponding conductor band (4, 6).

22. The feed unit (10) comprises two opposing compression rollers (17) between which the composite material (8) passes; each of said second cutting devices (18) is arranged upstream of two of said compression rollers (17); The manufacturing apparatus of claim 21.

23. The manufacturing apparatus according to any one of claims 1 to 22, wherein each of the winding heads (13) is rotatably mounted on the drum (11) so as to rotate relative to the drum (11) itself about a third axis of rotation (21) parallel to the second axis of rotation (12).

24. The manufacturing apparatus according to any one of claims 1 to 22, wherein each of the winding heads (13) is rotatably mounted on the drum (11) so as to rotate relative to the drum (11) itself about a third axis of rotation (21) parallel to the second axis of rotation (12) and about a fourth axis of rotation (23) parallel to the second axis of rotation (12).

25. The manufacturing apparatus according to any one of claims 1 to 22, wherein each of the winding heads (13) is rotatably mounted on the drum (11) so as to rotate relative to the drum (11) itself about a third axis of rotation (21) parallel to the second axis of rotation (12), about a fourth axis of rotation (23) parallel to the second axis of rotation (12), and about a fifth axis of rotation (24) parallel to the second axis of rotation (12).

26. each of said winding heads (13) is hinged to an end of a first arm (20) and rotates relative to said first arm (20) about said fifth axis of rotation (24); an end of the first arm (20) opposite the winding head (13) is hinged to an end of a second arm (22) and rotates relative to the second arm (22) about the fourth axis of rotation (23); an end of the second arm (22) opposite the first arm (20) is hinged to the drum (11) and rotates relative to the drum (11) about the third axis of rotation (21); The manufacturing apparatus according to claim 25.

27. A manufacturing apparatus according to any preceding claim, wherein the supply unit (10) is movably mounted to move forwards or backwards along a segment of the processing path (P2).

28. 28. The manufacturing apparatus of claim 27, wherein the supply unit (10) is rotatably mounted to rotate about the second axis of rotation (12).

29. 29. The manufacturing apparatus according to claim 27 or 28, comprising an actuation device configured to cause the supply unit (10) to cyclically perform a forward stroke in which the supply unit (10) synchronously follows a winding head (13) along a segment of the processing path (P2) and a return stroke in which the supply unit (10) returns to a starting position in order to synchronously follow a subsequent winding head (13).

30. A method for producing a cylindrical electrochemical cell (2) comprising a spiral winding of a composite material (8) having at least two conductor bands (4, 6) and at least two separator bands (5, 7) overlapping each other, comprising: rotating a first holding device (14) supported by a winding head (13) configured to grip one end of the composite material (8) about its first axis of rotation (15) so as to form a spiral winding of the composite material (8); moving a plurality of said winding heads (13) along a processing path (P2) by a drum (11) supporting said winding heads (13) and rotatably mounted for rotation about a second axis of rotation (12); feeding said composite material (8) to said winding head (13) by means of a feeding unit (10); Including, characterised in that the drum (11) rotates about the second axis of rotation (12) according to a continuous law of motion, Manufacturing method.

31. 31. The method of claim 30, wherein the step of feeding the composite material (8) to the winding head (13) comprises moving the composite material (8) at a substantially constant moving speed.

32. 32. The method according to claim 31, wherein the step of supplying the composite material (8) is performed without interrupting the movement of the composite material.

33. A method according to claim 30 or 32, wherein the composite material (8) moves along a linear movement path.

34. A method according to any one of claims 30 to 33, comprising moving the feed unit forwards or backwards along a segment of the processing path.

35. A battery (1) comprising an electrochemical cell (2) produced according to the method of any one of claims 30 to 34.

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