Method for manufacturing cylindrical electrical energy storage devices and apparatus for manufacturing electrical terminals of cylindrical electrical energy storage devices

Abstract

The method for forming electrical terminals of electric energy storage devices, in particular such as cylindrical electric batteries, involves making preferential fold lines on portions (4) of conducting material protruding along a longitudinal edge of flexible tape materials (3) configured to define the anode and cathode elements of a cylindrical winding (2) of the electric battery. Said preferential fold lines are defined by an orderly succession of fold lines (5) made on said protruding portions (4) of conducting material.

Description

DescriptionMETHOD FOR MANUFACTURING CYLINDRICAL ELECTRICAL ENERGY STORAGE DEVICES AND APPARATUS FOR MANUFACTURING ELECTRICAL TERMINALS OF CYLINDRICAL ELECTRICAL ENERGY STORAGE DEVICESTechnical Field

[0001] The present invention relates to a method for forming electrical terminals of electrical energy storage devices, such as in particular cylindrical electrical batteries, as well an apparatus for carrying out such a method.Prior art

[0002] Use of cylindrical electric batteries consisting of a cylindrical electrode winding, known in the specific industry as jelly roll, is currently known in the field of electrical energy storage devices. Such a cylindrical winding specifically comprises an anode element and a cathode element made in the form of flexible strips and separated from each other by a separator element. The electrode winding is placed inside a cylindrical container, possibily made of a metal material, normally filled with an electrolyte suitable for mediating the chemical reactions occurring between anode or cathode within the same container.

[0003] According to a known solution, from the anode and cathode elements are protruding, at opposite ends of the cylindrical winding, respective electrode terminals, known in the specific field as flags. The opposite ends of the cylindrical winding are usually associated with respective covers, made from metal disks made integral by welding to the electrode terminals of the cylindrical winding. In particular, for joining metal discs to electrical terminals, laser welding is emerging among the various available technologies.

[0004] For this purpose, electrical terminals are usually made by making a series of successive notches along the portion of the conducting material projecting substantially in the form of a spiral at the ends from the cylindrical winding, in such a way as to define individual flags, and subsequently bending said flags inward toward the cylindrical winding.

[0005] For example, US 2023 / 0402722 discloses an apparatus for making single flags, in which a cutting device makes through slits in the electrode sheets over the entire thickness of the sheet. To make the mentioned through slits, US 2023 / 0402722 discloses mechanical cutting or laser beam engraving as applicable techniques. Such flags are folded to make a common surface to which a collector disk made of electric current conducting material can be placed.

[0006] Similarly, WO 2022 / 226906 discloses the fabrication of transverse through cuts in the electrode sheets (anode and cathode) for obtaining single flags to be folded downstream of the winding of the anode sheets, cathode and the separators, defining a surface substantially perpendicular to the winding axis of the cylindrical element.

[0007] In the formation of cylindrical electric batteries, the formation of electric terminals is generally a critical step, both because of the cost involved in cutting individual flags andthe subsequent handling of those flags, which must be folded neatly inwards the cylindrical winding. Therefore, a need exists in the art for a different methodology for the formation of electrical terminals in electrical energy storage devices, which can overcome the mentioned limitations of the known technique.

[0008] As an alternative to the step of folding the flags, so as to obtain a common surface perpendicular to the winding axis of the cylindrical element, document EP 4 152 513 teaches making notches within the electrode sheet (anode or cathode), so that the protruding portions of the single electrode sheet are in contact with protruding portions of the adjacent layer once wrapped around the winding axis. In this way, once the anode, cathode and interposed separator sheets have been wrapped, the cylindrical element undergoes an axial extrusion step to further deform the protruding portions and in this way consolidate the physical contact of the end edge of the electrode sheets.Disclosure

[0009] The aim of the present invention is to solve the above-mentioned problems by devising a method to optimally carry out the formation of electric terminals of electric energy storage devices, in particular of the type of cylindrical electric batteries.

[0010] Within the scope of this task, it is further purpose of the invention to provide a method for forming electrical terminals of electrical energy storage devices that can simplify the operations required to manufacture said electrical terminals.

[0011] A further object of the invention is to provide a method for forming electrical terminals of electrical energy storage devices that does not require cutting individual flags.

[0012] A still further object of the invention is to provide an apparatus for carrying out said method that is of simple constructive and functional design, which is reliable in operation, has versatile use, as well as relatively inexpensive cost.

[0013] The above-mentioned purposes are achieved, according to the present invention, by the method for forming electric terminals of electric energy storage devices, such as in particular cylindrical electric batteries, according to claim 1.

[0014] Such electrical energy storage devices include a cylindrical winding consisting of at least one anode element, one cathode element, and one separator element interposed between said anode and cathode elements. According to an embodiment, the cylindrical winding has a pair of metal discs suitable for making contact with said electrical terminals of the anode and cathode elements, which are applied at opposite ends.

[0015] According to the present invention, the method for making electrical energy storage devices formed by wrapping at least one separator, one anode sheet and one cathode sheet, with the at least one separator between them, provides the steps of: a) arranging an anode sheet and a cathode sheet extending along a longitudinal direction and each comprising a respective first portion coated with arespective active electrode material and a respective second portion, which is not coated with active electrode material and which protrudes transversely from the first portion, the second portion having a longitudinal free edge; b) making a series of flags along the respective second portion of the anode and cathode sheets; c) wrapping the anode and cathode sheets with at least one separator sheet interposed around an axis of rotation, in a roll or jelly roll configuration resulting in a cylindrical electrical energy storage device; and d) folding the set of flags in a plane substantially perpendicular to and towards the axis of rotation.

[0016] Preferably, the step of a) arranging an anode sheet and a cathode sheet further provides for arranging a second separator sheet. Such a second separator sheet will be arranged adjacent to the anode sheet or cathode sheet and opposite to the first separator sheet with respect to the electrode sheet adjacent thereto, so that when all the four sheets are wound in a cylindrical configuration, the anode sheets and cathode sheets are always mutually isolated from the separator sheets.

[0017] Preferably, the step of c. wrapping the anode and cathode sheets with at least one separator sheet is carried out around a pin that serves as the axis of rotation of the jelly roll.

[0018] It is specified that the second portion of the anode sheet protrudes from the opposite side with respect to the second portion of the cathode sheet in the direction transverse to the feeding of the sheets.

[0019] In particular, the step of b. arranging the set of flags provides for making at least one transverse fold line between each pair of adjacent flags of said set of flags, so that the set of flags formed remains laterally united with each other by the at least one transverse fold line, each transverse fold line extending transversely with respect to the longitudinal direction from the free edge and defining a preferential fold line for the flags. This operation of making at least one transverse fold line will be repeated several times on the same second portion, leaving a distance in the longitudinal direction between two fold lines.

[0020] In addition, the step of c. folding the set of flags involves intercepting and folding the second portion by the relative movement of folding means with respect to the second portion.

[0021] Advantageously, making at least one transverse fold line consists of punctually reducingthe thickness of the second portion along such at least one transverse fold. Specifically, the thickness reduction will be at least 2% up to a maximum of 80%. According to an embodiment of the invention, the making of the at least one transverse fold line includes the making of a pair of fold lines converging toward the free edge of the second portion.

[0022] Similarly to the above, the making of at least one transverse bending line involves making a plurality of pairs of bending lines, with each pair of bending lines spaced apart from the adjacent one in the longitudinal direction.

[0023] This embodiment is particularly advantageous because the pair of converging fold lines helps to determine a pleated configuration during the folding phase according to both fold lines of the pair.

[0024] Advantageously, the stage in which the making of the at least one folding line takes place includes the rolling of the second portion by a pair of counter-rotating wheels while the second portion of the sheet slides between the wheels. Each wheel of the counter-rotating pair of wheels comprises notching means to make the at least one transverse bending line.

[0025] Preferably, a first pair of counter-rotating wheels engages the second portion of the anode sheet or the second portion of the cathode sheet; conversely, a second pair of counterrotating wheels engages the second portion of the cathode sheet or the anode sheet and opposite with repsect to the second portion of the other electrode sheet (anode or cathode).

[0026] Advantageously, the method further comprises a step of b2. making a longitudinal fold line along the longitudinal direction of feed of the the sheet. The longitudinal fold line is in close proximity to, preferably in contact with, the transverse fold lines.

[0027] According to an embodiment of undoubted interest of the present finding, the step of b2. making a longitudinal fold line is made at the same time as the step of b. preparing a series of flags in which the fold lines are made.

[0028] Advantageously, the method can provide that the step of d. folding the set of flags occures at the same time as the step c. of winding the anode and cathode sheets with at least one separator sheet.

[0029] Alternatively, the step of d. folding the set of flags may be carried out upon completion of step c. of wrapping the anode and cathode sheets with at least one separator sheet, that is, once the cathode and anode sheets and the at least one separator sheet between them have been wrapped all along their length aroundthe axis of the jelly roll.

[0030] According to an embodiment form of undoubted interest of the present invention, the folding means comprises a fixed folding body. Such a fixed folding body comprises a first engagement portion lying in a plane parallel to the first portion of the anode or cathode sheet, a second terminal portion lying in a second plane perpendicular to the axis of rotation, and a transition portion joining the engagement portion and the terminal portion trough an inclined surface. Specifically, the second portion of the sheet bends as it passes from the engagement portion to the end portion, passing through the curved portion interposed between the first and second portions of the fixed folding body.

[0031] Preferably, the transition portion is a curved surface uniting the engagement portion and the terminal portion seamlessly.

[0032] Even more preferably, the curved surface is of the quadric surface type, such as a cylindrical surface, spheroidal surface, a paraboloid, a hyperboloid of one or two flaps, or a combination of several types of curved surfaces.

[0033] According to alternative embodiments, the transition portion may comprise one or more flat portions lying on respective transition planes arranged between the engagement portion and the terminal portion.

[0034] As an alternative to the embodiment involving a fixed folding body, folding means may include a plurality of blades arranged circumferentially within an annular body. Such a plurality of blades is movable towards the central axis of the electrical energy storage device to fold the series of flags. In such a case, the step of (d) folding the set of flags is carried out after the step of (c) wrapping the anode and cathode sheets.

[0035] The present invention also relates to an apparatus for forming electrical energy storage devices of the type comprising a cylindrical winding formed by at least one separator sheet, an anode sheet, and a cathode sheet with one of the at least one separator sheet interposed between the anode sheet and the cathode sheet.

[0036] Preferably, a second separator sheet is arranged adjacent to the anode sheet or cathode sheet, opposite to the first separator sheet, so that when all the four sheets are wrapped in a cylindrical configuration, the anode sheets and cathode sheets are always mutually isolated from the separator sheets.

[0037] Specifically, the anode, cathode and the at least one separator sheets are made of flexible tape material. Each of the anode and cathode sheets, respectively, comprises a first portion coated with a respective active electrode material and a second portion developed longitudinally for at least part of the same anode or cathode sheet. The second portion of the anode or cathode sheet is not coated with active electrode element but with a metallic material that conducts the electrical energy. Such second portion of the electrode sheet protrudes transversely from the first portion, with the second portion having a free edge.

[0038] The apparatus for forming electrical energy storage devices comprises notching means configured to create at least one set of flags on the second portion of the electrode sheet by creating at least one transverse fold line on portions of conductive material protruding along a longitudinal edge of flexible tape materials configured to define said anode and cathode elements.

[0039] Preferably, the at least one fold line begins at the free edge of the second portion to extend substantially transverse to the boundary between the first and the second portion of the electrode sheet.

[0040] Preferably, the notching means is configured to make a partial notch on at least one of the two faces of the second protruding portion. Such partial notch will result in the definition of a preferential line of folding, in which the set of flags remain laterally united with respect to the longitudinal direction from the free edge.

[0041] Preferably, the notching means is configured to reduce the thickness of the second portion of the sheet by at least 2% up to 80 %, while still ensuring the continuity of the second portion of the sheet without generating through-cuts.

[0042] According to an embodiment of the invention, said notching means comprises a pair of counter-rotating wheels, in which the second protruding portion of the electrode sheet is interposed therebetween, in which each of the counter-rotating wheels comprises at least one notching tool acting from the opposite sides to the second protruding portions of the conductive material.

[0043] Preferably, each of the notching tools includes at least one transverse notching edge configured to make a transverse fold line from the longitudinal edge of the second portion of the electrode sheet toward the first portion thereof.

[0044] Even more preferably, each notching tool includes two converging transverse notching edges configured to make transverse fold lines, which are also converging. Specifically, the pair of converging notching edges converges at the notching point corresponding to the longitudinal edge of the second portion. In this way, the notching means is able to determine a set of flags with at least one main flag and one secondary flag, where the secondary flag can be appropriately pleated during or after the wrapping of the tape sheets.

[0045] Some embodiments of the present invention also provide for the notching tools to further include a longitudinal edge, suitable for defining a longitudinal fold line on the second portion of the electrode sheet. In this way, the longitudinal fold line will further help fold the set of flags in a plane perpendicular to the axis of rotation of the cylindrical device.

[0046] It is specified that this longitudinal fold line is not strictly necessary because the at least one separator sheet and the other electrode sheet serve as the physical support for the folding of the second protruding portion, as the second portion of the electrode sheetprotrudes transversely from the first portion of the electrode sheet, but also from the other electrode sheet and the separator sheets.

[0047] Preferably, each of the counter-rotating wheels rotates around an its own axis of rotation, in which the axis of rotation of the first wheel is essentially parallel to the axis of rotation of the second wheel of the pair.

[0048] Preferably, both wheels are coupled to ensure coordinated operation of the two counterrotating wheels in order to ensure that the bending lines are created accurately. For example, wheels can be coupled together by a mechanical device, such as a gear shaft. Alternatively, counter-rotating wheels can be coupled by electronic cams.

[0049] It is specified that notching means comprising a pair of counter-rotating wheels is arranged at the second portion of the electrode sheet, regardless of whether it is the anode sheet or the cathode sheet. Therefore, this notching means will be replicated from the other cross-sectional end, i.e. , a second unit of notching means will be arranged at the second portion of the other electrode sheet, e.g., the cathode sheet if the first pair of counter-rotating wheels was arranged at the second portion of the anode sheet and vice versa.

[0050] According to one aspect of the invention, the apparatus includes winding means for winding the anode sheets, cathode sheets, and the at least one separator sheet interposed between the anode and cathode sheets around a rotational axis of the cylindrical electrical energy storage device.

[0051] Preferably, a second separator sheet is opposed to the first with an electrode sheet in between so that, during the winding of the four sheets, the anode and cathode sheets are properly separated by the separator sheets.

[0052] Preferably the winding means comprises a winding pin. Such a winding pin exerts restraint on the end of the sheets.

[0053] Preferably, the pin exerts restraint on the end of at least one separator sheet to initiate winding around the axis of rotation.

[0054] According to one aspect of the invention, the apparatus further includes folding means configured to intercept and deflect the set of flags of the second portion of the electrode sheet provided with at least one folding line. The action of intercepting and diverting consists of folding the second protruding portions of conducting material. This action is accomplished by the relative movement of the folding means with respect to the projecting second portions, so as to fold the set of flags of the projecting second portions in a plane substantially perpendicular to the axis of rotation of the cylindrical electrical energy storage device.

[0055] It is specified that first folding means is arranged at the longitudinal edge of the second portion of the first electrode sheet (anode or cathode), and second folding means isarranged at the longitudinal edge of the second portion of the second electrode sheet (cathode or anode).

[0056] According to an embodiment of the invention, the folding means includes at least one fixed abutment body, arranged facing and close to one of the sides of the tape materials being wound, so as to intercept and deflect the set of flags of the second protruding portions with at least one transverse folding line thereon.

[0057] According to an embodiment of the invention, the fixed body of the foding means includes an engagement portion lying in a horizontal plane parallel to the first portion of the electrode sheet, an end portion lying in a second plane perpendicular to the axis of rotation of the cylindrical device, and a transition portion with a inclined surface uniting the engagement portion and the end portion. Specifically, the second portion of the sheet bends as it passes from the engagement portion to the end portion, passing through the curved portion interposed between the first and second portions of the fixed bending body.

[0058] Preferably, the transition portion is a surface seamlessly uniting the engagement portion and the terminal portion.

[0059] According to an embodiment of the invention, the transition portion of the fixed body is a curved surface configured to progressively fold the series of flags of the second portion of electrode sheet, and simultaneously the same slides on the fixed abutment body of the folding means while the first portion of electrode sheet made of flexible material slides along the feed plane.

[0060] Preferably, the curved surface is of the quadric surface type, such as a cylindrical surface, spheroidal surface, a paraboloid, a hyperboloid of one or two flaps, or a combination of several types of curved surfaces.

[0061] Alternatively, the transition portion may include one or more flat portions lying on respective transition planes arranged between the engagement portion and the terminal portion.

[0062] According to a different embodiment of the invention, the folding means includes diaphragm means, acting after that the winding of the tape materials in cylindrical form is completed.

[0063] The diaphragm means comprises a fixed annular body provided with a hole inside with an opening adjustable by a plurality of movable blades arranged circumferentially on the annular body, with the blades pivoting equidistantly on the annular body to be moved coordinately towards the axis of rotation of the cylindrical energy storage device, to bend the set of flags of the second portion of the electrode sheet.Description of drawings

[0064] The details of the invention will be more apparent from the detailed description of a preferred embodiment of the method and apparatus for forming electric energy storagedevices, such as cylindrical electric batteries, illustrated by way of example in the attached drawings, in which:Figure 1 shows a schematic perspective view of an electrode sheet (anode or cathode) arranged for forming cylindrical electric batteries according to the present invention;Figure 2 shows a schematic perspective view of the electrode sheet (anode or cathode) during the process of making the fold lines;Figure 2a shows a view of an enlarged detail of Fig. 2;Figure 3 shows an enlarged front view of the second protruding portion bearing fold lines made thereon;Figures 4 and 5 respectively show a schematic perspective view, from different points of view, of the electrode sheet (anode or cathode) during the winding step;Figures 6 and 7 respectively show a perspective view, at different working steps, of a folding device of the second protruding portion bearing fold lines made thereon;Figures 8 and 9 show corresponding frontal views;Figure 10 shows a perspective view of a cylindrical electrical energy storage device according to the present invention;Figures 11 and 12 show a front view of the series of flags laterally joined and suitably folded in a pleated configuration from the outer and inner sides of the cylindrical electrical energy storage device, respectively.Description of embodiments of the invention

[0065] With particular reference to these figures, an electrical energy storage device, such as in particular electric batteries constituted of a cylindrical winding or jelly roll 2 consisting of at least one anode sheet, one cathode sheet, and at least one separator sheet interposed between said anode and cathode sheets, has been referred to on the whole as 1 ; the cylindrical winding 2 is placed inside a cylindrical container, such as one made of a metallic material, normally filled with an electrolyte suitable for mediating the chemical reactions occurring between anode or cathode within the same container.

[0066] The anode and cathode sheets and the at least one interposed separator sheet are made, in a known manner, in the form of flexible tapes, hereafter referred to as reference numeral 3.

[0067] The present method for forming the electrical terminals of the cylindrical winding or jelly roll 2 involves arranging at least one anode sheet and at least one cathode sheet consisting of flexible tape materials 3 having, along a respective longitudinal edge 4a of a first portion of the electrode sheet, a second protruding portion or appendage 4 developed longitudinally for at least part of the same anode and cathode sheets (Figures 1 and 3). Such second portion 4 of electrode sheet also has a longitudinal edge 4b.

[0068] Along the second protruding portion 4 of the anode sheet and cathode sheet, respectively,an orderly succession of transverse fold lines 5 is made, configured to define preferential bending lines of the same protruding portion 4 (Fig. 2). Specifically, the transverse fold lines 5 start from the longitudinal edge 4b of the second portion 4 of electrode sheet.

[0069] In the case at issue, the fold lines 5 are made by a pair of counter-rotating wheels 6 acting from opposite sides to the said protruding portion 4 of the anode and cathode elements. Notching wheels 6 peripherally have special notching tools 7.

[0070] As shown in the detail of Figure 2a, the notching tools can have a first transverse notching edge, configured to make a first transverse fold line 5a on the second portion 4 of electrode sheet, where the fold line starts from the longitudinal edge 4b of the same (fig. 3). Advantageously, the notching tool 7 can be provided with a second transverse notching edge 7b configured to make a second transverse fold line 5b on the second portion 4 of electrode sheet, where the second transverse fold line 5b starts from the longitudinal edge 4b of the same. In this case, the first notching edge 7a and the second notching edge 7b will be converging at one point, so that the transverse fold lines 5a, 5b are converging and intersecting on the outer longitudinal edge 4b of the second portion 4 of the sheet.

[0071] Advantageously, the notching tool 7 can further include a third longitudinal notching edge 7c, configured to determine a longitudinal fold line 5c that assists the bending of the set of flags of the second portion in a plane perpendicular to the axis 2a of the cylindrical energy storage element 2. Such a longitudinal fold line will be made on the second portion 4 almost at the longitudinal edge 4a joining the first and second portions 4 of electrode sheet and substantially parallel thereto.

[0072] As visible in Fig. 3, illustrating an enlarged frontal view of said protruding portion 4, the fold lines 5 have in the specific case a pair of features 5a, 5b converging toward the outer longitudinal 4b edge of the second protruding portion 4. However, it is possible, of course, to provide for the fold lines to have different shapes as required, for example, depending on the diameter of the cylindrical winding or the type of materials used.

[0073] With this specific configuration, the notching means will generate at least one main 5d flag with a trapezoidal shape, preferably a plurality of main 5d flags, and at least one secondary 5e flag with a substantially triangular shape, preferably a plurality of secondary 5e flags. In this way, during the folding step the main 5d and secondary 5e flags will overlap generating a pleated petal or artichoke configuration but simultaneously ensuring the lateral union of the 5d, 5e flags folded over each other.

[0074] Then, said set of flags are folded from the second protruding portion 4 of the anode and cathode sheets, respectively, on a plane substantially perpendicular to the axis of rotation 2a of the cylindrical storage device 2 (Figures 4 and 5). Appropriately, such folding takes place simultaneously with the winding of the anode and cathode sheets and the at leastone separator sheet interposed in cylindrical form. To this end, the apparatus includes winding means 20 for winding said anode sheets, cathode sheets, and at least one separator sheet interposed between the anode and cathode sheets around the axis of rotation 2a of the cylindrical electrical energy storage device.

[0075] According to the present invention, the folding of the set of flags 5d, 5e of the respective second protruding portions at said transverse fold lines 5, 5a, 5b configured to define preferential fold lines is thus determined.

[0076] In the case illustrated in Figures 4 and 5, folding is performed by the use of fixed folding means 8 arranged at the side of the tape materials 3 during the winding step, so as to intercept and deflect the second protruding portions 4 equipped with said fold lines 5, 5a, 5b. However, of course, it is possible to provide for the use of different folding means of the protruding portions equipped with said fold lines, as required.

[0077] In particular, the folding means includes a fixed folding body 8. Said fixed folding body 8 comprises a first engagement portion 8a lying in a plane H parallel to the first portion of the anode or cathode sheet; a second end portion 8c lying in a second plane V perpendicular to the axis of rotation 2a; and a transition portion 8b joining the engagement portion 8a and the end portion 8c through an inclined surface. Specifically, the second sheet portion 4 folds as it passes from the engagement portion 8a to the end portion 8c, passing through the curved portion 8b interposed between the first portion 8a and the second portion 8c of the fixed folding body 8.

[0078] In the particular case shown in Figures 4 and 5, the transition portion 8b is a curved surface uniting the engagement portion and the terminal portion seamlessly. Specifically, the curved surface is of the quadric surface type, such as a cylindrical surface, spheroidal surface, a paraboloid, a hyperboloid of one or two flaps, or a combination of several types of curved surfaces.

[0079] Figures 6 - 9 illustrate as an example the folding of the series of flags made on the second protruding portions 4 equipped with said fold lines 5, 5a, 5b by diaphragm means 9, acting after the the winding of the tape materials in cylindrical form is completed. Such diaphragm 9 means comprises a fixed ring 10 having a hole with an opening adjustable by means of a plurality of pivoted thin plates 11 of falcate shape equidistant on the same fixed ring. The thin plates 11 may be rotated synchronously so as to vary the diameter of the circle they circumscribe. The tightening of the circle (see Figures 7 and 9) results in the progressive bending of said protruding portions at said fold lines configured to define preferential fold lines.

[0080] At the end of the folding step, the cylindrical or jelly roll 2 electrical energy storage device (Fig. 10) has at the opposite ends a rim 14 of conducting material of the second portion 4 of electrode sheet that is developed in a plane substantially perpendicular to the axis 2a ofthe wound cylindrical device 2 defined by the folding of the series of flags 5d, 5e of the second protruding portions 4 according to the preferential fold lines defined by the fold lines 5, 5a, 5b made.

[0081] Such a rim 14 of conducting material makes, at each end of the cylindrical winding 2, an electrical terminal of the electric battery. In the specific embodiment described in nonlimiting form, the eim 14 of conducting material will then be associated with a metal collector disc of front cover of the electric battery. It is noteworthy that such a rim 14 of conducting material has essentially no discontinuities from the outer side to the product (Fig. 11 ), while on the inner side there are the flaps in pleated configuration, with the secondary flags 5e of basically triangular shape, defined at the folding step of said projecting portions 4 (fig. 12).

[0082] The method for manufacturing electric energy storage devices, such as cylindrical electric batteries in particular, is easily understandable from the above description.

[0083] The method and the apparatus that implements it achieve the aim of optimally forming electric terminals of electric energy storage devices, of the type in particular of cylindrical electric batteries.

[0084] In particular, the subject method makes it possible to simplify the operations required to manufacture said electrical terminals, thanks specifically to the fact that it does not require the cutting of individual flags, e.g., by laser means that is complex and expensive.

[0085] The apparatus described as an example is susceptible of numerous modifications and variations according to the various requirements.

[0086] In the practical embodiment of the invention, the materials used, as well as the shape and the dimensions, may be modified depending on needs without departing from the scope of the appended claims.

[0087] Should the technical features mentioned in any claim be followed by reference signs, such reference signs were included strictly with the aim of enhancing the understanding of the claims and hence they shall not be deemed restrictive in any manner whatsoever on the scope of each element identified for exemplifying purposes by such reference signs.

Claims

Claims1. A method for manufacturing cylindrical electrical energy storage devices formed by winding at least one anode element, one cathode element, and one separator element interposed between said anode and cathode elements, comprising the steps of a. arranging an anode sheet and a cathode sheet extending along a longitudinal direction and comprising a respective first portion coated with a respective active electrode material and a respective second portion (4), which is not coated with active electrode material and which protrudes transversely from the first portion, said second portion having a longitudinal free edge (4b); b. making a set of flags along said respective second portion (4) of the anode and cathode sheets; c. winding the anode and cathode sheets around an axis of rotation (2a) with a separator sheet interposed therebetween in a roll configuration in order to form a cylindrical electrical energy storage device; d. folding the set of flags on a plane substantially perpendicular to the axis of rotation (2a) by folding means (8, 9), wherein said step of b. making a set of flags involves making at least one fold line (5) transversal between each pair of adjacent flags of said set of flags, so that the flags of said formed set of flags remain joined laterally to each other, each fold line (5) transversely extending transversely from the longitudinal direction from the free edge (4b) and defining a preferential fold line for the flags, and wherein said step of d. folding the set of flags involves intercepting and folding said second portion (4) by the relative movement of said folding means (8, 9) with respect to the same second portion (4).

2. The method of claim 1 , wherein said step of b. making a set of flags consists of reducing the thickness of the second portion (4) along said transverse fold lines (5) from at least 2 % up to 80 %.

3. The method of claim 1 or 2, wherein said step of b. making a set of flags includes making a pair of fold lines (5a, 5b) converging to the free edge (4b) of the second portion (4) between each pair of adjacent flags (5d, 5e).

4. The method of any one of the preceding claims, wherein said step of b. making a set of flags involves rotating a pair of counter-rotating wheels (6) equipped with notching means (7) to make at least one transverse fold line (5, 5a, 5b) on the second portion (4) as the respective sheet slides therebetween along the longitudinal direction.

5. The method of any one of the preceding claims, wherein it includes the further step ofb2. making a longitudinal fold line (5c) in the second portion (4) along the longitudinal direction of sheet feed, near, preferably in contact with, the at least one transverse fold line (5, 5a, 5b).

6. The method of claim 5, wherein the step of b2. making the longitudinal fold line (5c) is carried out at the same time as the step of b. preparing a set of flags in which the fold lines are made.

7. The method of any one of the preceding claims, wherein the step of d. folding the set of flags is carried out at the same time as the step of c. winding the anode and cathode sheets with at least one separator sheet.

8. The method of any one of the preceding claims, wherein said folding means (8) comprises a fixed folding body (8), said folding body (8) fixed comprising a first engagement portion (8a) lying on a plane (H) parallel to the first portion of the anode or cathode sheet, a second end portion (8c) lying on a second plane (V) perpendicular to the axis of rotation (2a), and a curved portion (8b) seamlessly joining the engagement portion (8a) and the end portion (8c) through an inclined surface, where the second portion (4) of the electrode sheet bends by passing from the engagement portion (8a) to the end portion (8c), through the curved portion (8b).

9. The method of any to one of claims 1 - 6, wherein said step of d. folding the set of flags is carried out after said step of c. winding around an axis of rotation (2a) the anode and cathode sheets, where said folding means (9) carrying out said step of d. folding the set of flags comprise a plurality of blades (11) arranged circumferentially within a fixed annular body (10), and wherein said plurality of blades (11) is movable simultaneously towards the axis of rotation (2a) of the electric energy storage device to fold the array of flags of the second portion (4) of the electrode sheet.

10. An apparatus for manufacturing the electrical terminals of cylindrical electrical energy storage devices formed by winding at least one anode sheet, one cathode sheet, and one separator sheet interposed between said anode and cathode sheets, in which said anode and cathode sheets of flexible tape materials (3) comprise a first portion coated with a respective active electrode material and a respective second portion (4), extended longitudinally for at least a portion of the same anode and cathode sheets, said second portion (4) not being coated with an active electrode material and protruding transversely from the first portion, said second portion (4) having a longitudinal free edge (4b), said apparatus comprising: notching means (6) configured to create at least one set of flags on said second portion (4) of the electrode sheet by creating at least one transverse fold line (5, 5a, 5b) between each pair of adjacent flags of said set of flags, so that the flags of said set of formed flagsremain joined laterally to each other, each transversal fold line (5, 5a, 5b) transversally extending with respect to the longitudinal direction from the free edge (4b) and defining a preferred fold line for the flags; winding means (20) for winding said anode sheets, cathode sheets, and at least one separator sheet interposed between the anode and cathode sheets around a rotation axis (2a) of the cylindrical electrical energy storage device; and folding means (8, 9) configured to intercept and fold said set of laterally joined flags of said laterally projecting portions (4) by at least one transverse folding line (5) by means of a relative movement of the folding means (8, 9) with respect to the same second projecting portions (4), so as to bend said sets of flags of said second portions (4) in a plane substantially perpendicular to the axis of rotation (2a) of the cylindrical electrical energy storage device.

11. The apparatus of claim 10, wherein said notching means (6) comprises a pair of counterrotating wheels (6), in which the second portion (4) protruding from the electrode sheet is interposed therebetween, each of the counter-rotating wheels (6) comprising at least one notching tool (7) acting from opposite sides of the second portion (4) of the conductive material.

12. The apparatus of claim 10 or 11 , wherein said folding means (8) comprises at least one fixed abutment body, arranged facing and close to one side of the tape material during the winding step, so as to intercept and deflect the set of flags of said second portions (4) with at least one folding line (5) transverse thereon.

13. The apparatus of claim 12, wherein said fixed abutment body of the folding means (8) comprises an engagement portion (8a) lying on a plane (H) parallel to the first electrode sheet portion, an end portion (8c) lying in a second plane (V) perpendicular to the axis of rotation (2a) of the cylindrical device, and a transition portion (8b) with an inclined surface uniting seamlessly the engagement portion (8a) and the end portion (8c), wherein the second portion (4) of electrode sheet bends as it passes from the engagement portion (8a) to the end portion (8c), passing through the transition portion (8b).

14. The apparatus of claim 13, wherein said transition portion (8b) of the fixed body is a curved surface configured to progressively fold said set of flags of the second portion of electrode sheet at the same time that the same slides on the fixed abutment body of said folding means (8) while the first portion of electrode sheet made by a flexible material element (3) slides along the feed plane.

15. The apparatus according to claim 10 or 11 , wherein said folding means (9) comprises diaphragm means, acting after the winding of said tape materials (3) in cylindrical form is completed, where said diaphragm means comprises a fixed annular body (10) provided inside with a hole having an opening adjustable by a plurality of movable blades (11)arranged circumferentially and pivoting equidistantly on said annular body (10) to be moved together towards the axis of rotation (2a) of the electrical energy storage device, for bending the set of flags of the second portion of the electrode sheet.

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