Method for making electrochemical cells and apparatus for making electrochemical cells

Abstract

A method for making electrochemical cells comprises arranging first foils (100) of a first electrode precursor coplanar to each other and according to a matrix pattern with N rows and M columns, arranging second foils (110) of a second electrode precursor coplanar to each other and according to a matrix pattern with N rows and M columns, arranging, as coplanar to each other, first separator sheets (120) arranged according to a matrix pattern with N rows and M columns, arranging, as coplanar to each other, second separator sheets (130) arranged according to a matrix pattern with N rows and M columns, stacking the first separator sheets (120), the first foils (100), the second separator sheets (130) and the second foils (110) with each other to make an N*M number of stacking groups (140) arranged according to a matrix pattern with N rows and M columns wherein each stacking group (140) comprises at least a first separator sheet (120), a first foil (110), a second separator sheet (130) and a second foil (100) at least partially overlapping on each other.

Description

[0001] “Method for making electrochemical cells and apparatus for making electrochemical cells”

[0002] DESCRIPTION

[0003] The present invention relates to a method for making electrochemical cells and an apparatus for making electrochemical cells, wherein electrode precursors and dielectric separator sheets are stacked with each other according to a predetermined stacking pattern.

[0004] The present invention can be used to make secondary batteries or capacitors, comprising planar electrodes separated from each other by a dielectric separator.

[0005] In the industrial sector of the production of electric accumulators, electrochemical cells are produced made from stacks of positive and negative electrode precursors, arranged alternately one above the other, with a separation layer of dielectric material interposed, generally indicated in the technical jargon of the sector with the term “separator”.

[0006] Such electrochemical cells are usually made by stacking a positive electrode precursor on a separator sheet, stacking a further separator sheet on the positive electrode precursor, and stacking a negative electrode precursor on the further separator sheet to obtain a first stacking group. This operation is repeated by stacking as many stacking groups on above the other as necessary to obtain the desired electrical characteristics of the electrolytic cell. By adding an electrolyte to the stacking group, ions can migrate between anode and cathode transforming the electrode precursors into electrodes and the electrochemical cell into a battery.

[0007] Electrode precursors are substantially made by depositing a layer of active material for electrodes on one surface or on both surfaces of a current collector metal foil. By choosing a suitable combination of active material for electrodes and of material of the current-collecting metal foil, it is possible to obtain electrode precursors intended for making positive electrodes and electrode precursors intended for making negative electrodes.

[0008] In Applicant's experience, the positive and negative electrode precursors are cut into square or rectangular-shaped foils of desired dimensions (corresponding to the dimensions that the electrolytic cell must have) from respective coils of positive and negative electrode precursor previously sectioned into strips with width substantially equal to one of the dimensions of the electrode precursor foils.

[0009] Similarly, the separator sheets are cut into square or rectangular-shaped sheets of desired dimensions (proportional to the dimensions of the electrode precursor foils) from respective separator coils previously sectioned into strips with width substantially equal to one of the dimensions of the separator sheets.

[0010] The positive electrode precursor foils thus obtained are temporarily stored (very often by stacking them on top of each other), as well as the negative electrode precursor foils and the separator sheets are temporarily stored (very often by stacking them on top of each other).

[0011] When the electrolytic cells are to be made, the positive electrode precursor foils, the negative electrode precursor foils and the separator sheets are fed to a stacking apparatus which in succession withdraws a separator sheet, a positive electrode precursor foil, a further separator sheet and a negative electrode precursor foil stacking them in a stacking station and making an electrochemical cell.

[0012] In the Applicant's experience, the need is increasingly felt, particularly in the industrial sector of the production of electrical accumulators, to be able to have methods and apparatuses for making electrochemical cells that allow high production rates, that is, that allow high speeds of production of electrochemical cells.

[0013] The Applicant has noted that the stacking operations of the electrode precursors and separator sheets require an execution time that substantially results in and imposes an upper limit on the production rate of electrochemical cells.

[0014] The Applicant has noted that the time required to make a single electrochemical cell could be reduced by increasing the withdrawal rate of the electrode foils and of the separator sheets from the respective stacks, the speed of transfer to the stacking station, and the speed of deposition of the electrode foils and separator sheets in the stacking station.

[0015] However, the Applicant has verified that the required stacking precision of the electrode foils and separator sheets in the stacking station does not allow consistent speed increases at least during the step of withdrawing and deposition of the electrode foils and separator sheets. The Applicant has perceived that if not just one electrode foil and one separator sheet at a time but a plurality of electrode foils and separator sheets were withdrawn, transferred and deposited in the stacking station, it would be possible to simultaneously make a plurality of electrochemical cells at a time even without increasing the withdrawal and deposition speeds of the electrode foils and separator sheets, therefore without sacrificing the time necessary to guarantee the required stacking precision.

[0016] The Applicant has therefore found that by arranging foils of a first electrode precursor, foils of a second electrode precursor and separator sheets according to respective matrix patterns with N rows and M columns and by stacking the separator sheets and the electrode precursor foils with each other making an N*M number of stacking groups arranged according to the same matrix pattern with N rows and M columns, it is possible to simultaneously make an N*M number of electrochemical cells.

[0017] The present invention therefore concerns, in a first aspect thereof, a method for making electrochemical cells.

[0018] Preferably, it is provided to arrange first foils of a first electrode precursor coplanar to each other and according to a matrix pattern with N rows of first foils and M columns of first foils.

[0019] Preferably, each first foil is physically separated from the other first foils.

[0020] Preferably, it is provided to arrange second foils of a second electrode precursor coplanar to each other and according to a matrix pattern with N rows of second foils and M columns of second foils.

[0021] Preferably, each second foil is physically separated from the other second foils.

[0022] Preferably, it is provided to arrange, as coplanar to each other, first separator sheets arranged according to a matrix pattern with N rows of first separator sheets and M columns of first separator sheets.

[0023] Preferably, it is provided to arrange, as coplanar to each other, second separator sheets arranged according to a matrix pattern with N rows of second separator sheets and M columns of second separator sheets.

[0024] Preferably, it is provided to stack said first separator sheets, said first foils, said second separator sheets and said second foils with each other to make an N*M number of stacking groups arranged according to a matrix pattern with N rows and M columns.

[0025] Preferably, each stacking group comprises at least a first separator sheet, a first foil, a second separator sheet and a second foil, at least partially overlapping on each other.

[0026] The present invention concerns, in a second aspect thereof, an apparatus for making electrochemical cells.

[0027] Preferably, there is provided a first plane configured to receive first foils of a first electrode precursor coplanar to each other and according to a matrix pattern with N rows of first foils and M columns of first foils.

[0028] Preferably, each first foil is physically separated from the other first foils.

[0029] Preferably, there is provided a second plane configured to receive second foils of a second electrode precursor coplanar to each other and according to a matrix pattern with N rows of second foils and M columns of second foils.

[0030] Preferably, each second foil is physically separated from the other second foils.

[0031] Preferably, there is provided a separator plane configured to receive first separator sheets arranged according to a matrix pattern with N rows of first separator sheets and M columns of first separator sheets and to receive second separator sheets arranged according to a matrix pattern with N rows of second separator sheets and M columns of second separator sheets.

[0032] Preferably, transfer members are provided movable between said first plane and a stacking station, movable between said second plane and the stacking station and movable between said separator plane and the stacking station.

[0033] Preferably, said transfer members comprise a plurality of retaining elements according to a matrix pattern with N rows of retaining elements and M columns of retaining elements.

[0034] The Applicant has verified that by stacking the first separator sheets arranged coplanar to each other and according to a matrix pattern with N rows and M columns, the first foils arranged coplanar to each other and according to a matrix pattern with N rows and M columns, the second separator sheets arranged coplanar to each other and according to a matrix pattern with N rows and M columns and the second foils arranged coplanar to each other and according to a matrix pattern with N rows and M columns to make an N*M number of stacking groups arranged according to a matrix pattern with N rows and M columns, it is possible to simultaneously produce N*M electrochemical cells each of which is provided with a cathode foil and an anode foil.

[0035] The Applicant has also verified that the above actions can be repeated a predetermined number of times at will to obtain stacking groups each of which provided with a predetermined number of cathode foils and anode foils, so as to be able to make N*M batteries (once the electrolyte has been added to the electrochemical cells) with desired electrical characteristics.

[0036] At each repetition of the above actions a layer of cathode foils, of anode foils and of separator sheets is added to the already made stacking group.

[0037] “Foil” means a plate having two dimensions much larger than a third dimension. The foil can be a monolithic plate or a plate formed by a plurality of layers joined together of identical material or of different materials.

[0038] “Direction perpendicular” to a foil or sheet means a direction perpendicular to a lying plane of the foil or sheet. A direction perpendicular to an electrochemical cell or to a stacking group is understood to be a direction that crosses all the layers of the electrochemical cell or of the stacking group and that is perpendicular to the lying planes of the various layers, where the layers are understood to be the electrode foils and the separator sheets.

[0039] “Matrix pattern” means an arrangement that provides for objects that are homogeneous or preferably identical to each other arranged so as to form ordered rows and columns, wherein each row of objects is parallel to the other rows of objects and wherein each column of objects is parallel to the other columns of objects. An example of a matrix pattern is given by positioning of objects at the intersections between a first bundle of lines parallel to each other and a second bundle of lines parallel to each other and perpendicular to the first bundle of lines.

[0040] “Cantilevered” when referred to a first element relative to a second element, means that the first element is projecting beyond the second element in such a way as to protrude relative to the overall dimensions of the second element. For example, when a first element is cantilevered relative to a second element, the first element projects beyond the second element and, in its projecting portion, the first element is not overlapped on the second element.

[0041] “Pre-weakening line” means a line, continuous or made up of a plurality of successive sections, along which a material in sheet form has been weakened. Along a pre-weakening line, a privileged direction for tearing the sheet is achieved. An example of a pre-weakening line may be a non-passing incision in the sheet, i.e. an incision that does not pass through the thickness of the sheet. A pre-weakening line can be made on only one surface of the sheet or on both surfaces of the sheet.

[0042] “Notch” means an incision through a sheet, that is, an incision that completely crosses the thickness of the sheet.

[0043] The present invention may have, in one or more of its aspects, at least a of the preferred features described below. Such features may be present individually or in combination with each other, unless expressly stated otherwise, both in the apparatus and in the method of the present invention.

[0044] Preferably, N is an integer greater than 1 .

[0045] Preferably, M is an integer greater than 1 .

[0046] By way of example, in the case where N is equal to 8 and M is equal to 10, the matrix pattern with N rows of first foils and M columns of first foils provides that the first foils are arranged according to 8 rows and 10 columns, for a total of 80 first foils.

[0047] Preferably, said first foils, said second foils, said first separator sheets and said second separator sheets are arranged according to the same matrix pattern with N rows and M columns.

[0048] Preferably, stacking said first separator sheets, said first foils, said second separator sheets and said second foils with each other comprises transferring simultaneously all the first separator sheets to a stacking station maintaining said matrix pattern with N rows and M columns.

[0049] This action is carried out by the transfer members which comprise a plurality of retaining elements arranged according to a matrix pattern with N rows of retaining elements and M columns of retaining elements and which withdraw simultaneously all the first separator sheets and retain them through the retaining elements. Preferably, each retaining element of said plurality of retaining elements retains a respective first separator sheet.

[0050] Preferably, each retaining element comprises a suction device for retaining a respective first separator sheet by effect of air suction.

[0051] Preferably, stacking said first separator sheets, said first foils, said second separator sheets and said second foils with each other comprises, after transferring all the first separator sheets, transferring simultaneously all the first foils to the stacking station maintaining said matrix pattern with N rows and M columns and laying the first foils on top of the first separator sheets.

[0052] This action is carried out by the transfer members which comprise a plurality of retaining elements arranged according to a matrix pattern with N rows of retaining elements and M columns of retaining elements and which withdraw simultaneously all the first foils and retain them through the retaining elements.

[0053] Preferably, each retaining element of said plurality of retaining elements retains a respective first foil.

[0054] Preferably, each retaining element comprises a suction device for retaining a respective first foil by effect of air suction.

[0055] Preferably, stacking said first separator sheets, said first foils, said second separator sheets and said second foils with each other comprises, after transferring all the first foils, transferring simultaneously all the second separator sheets to the stacking station maintaining said matrix pattern with N rows and M columns and laying the second separator sheets on top of the first foils.

[0056] This action is carried out by the transfer members which withdraw simultaneously all the second separator sheets and retain them through the retaining elements.

[0057] Preferably, each retaining element retains a respective second separator sheet.

[0058] Preferably, each retaining element comprises a suction device for retaining a respective second separator sheet by effect of air suction.

[0059] Preferably, stacking said first separator sheets, said first foils, said second separator sheets and said second foils with each other comprises, after transferring all the first separator sheets, transferring simultaneously all the second foils to the stacking station maintaining said matrix pattern with N rows and M columns and laying the second foils on top of the second separator sheets.

[0060] This action is carried out by the transfer members which withdraw simultaneously all the second foils and retain them through the retaining elements.

[0061] Preferably, each retaining element retains a respective second foil.

[0062] Preferably, each retaining element comprises a suction device for retaining a respective second foil by effect of air suction.

[0063] Preferably, transferring simultaneously all the first separator sheets to the stacking station is implemented with said first separator sheets partially physically connected to each other.

[0064] The Applicant has found that in this way the first separator sheets create a physical connection between the plurality of stacking groups that are deposited in the stacking station. This makes the matrix pattern with stacking groups more stable, i.e. it tends to prevent the various stacking groups from being able to move relative to each other in the stacking station. The Applicant has verified that this is very advantageous when electrochemical cells having a plurality of stacking groups overlapped on each other are made in the stacking station. The Applicant has indeed noted that as the electrochemical cells being formed in the stacking station develop in height, their stability tends to decrease. By arranging separator sheets partially physically connected therebetween, the structural stability of the electrochemical cells is not compromised as the electrochemical cells develop in height.

[0065] Preferably, it is provided that said first separator sheets are physically separated from each other after stacking said first separator sheets, said first foils, said second separator sheets and said second foils with each other.

[0066] Preferably, it is provided that said first separator sheets are physically separated from each other after completing said stacking groups in said stacking station.

[0067] Alternatively or in combination with transferring all the first separator sheets to the stacking station with said first separator sheets partially physically connected to each other, it is preferably provided that transferring simultaneously all the second separator sheets to the stacking station is implemented with said second separator sheets partially physically connected to each other.

[0068] In this case, it is preferably provided that said second separator sheets are physically separated from each other after stacking said first separator sheets, said first foils, said second separator sheets and said second foils with each other.

[0069] Preferably, it is provided that said second separator sheets are physically separated from each other after completing said stacking groups in said stacking station.

[0070] This action is preferably carried out when each electrochemical cell must be withdrawn to make a respective battery.

[0071] Preferably, the first separator sheets, or alternatively or in combination the second separator sheets, are partially physically connected to each other through pre-weakening lines preferably alternated with notches.

[0072] The Applicant believes that the operation of separating the electrochemical cells from each other must be able to be carried out without introducing excessive forces or stresses within the matrix pattern of the electrochemical cells. The Applicant has in fact verified that if the first separator sheets (and / or the second separator sheets) were subjected to high separation forces, these forces could cause misalignment between the components of the individual electrochemical cells (i.e. the first foils, the second foils, the first separator sheets and the second separator sheets) and of the electrochemical cells therebetween. The Applicant has found that by holding the first separator sheets (and / or the second separator sheets) joined together by pre-weakening lines, preferably alternated with notches, the force required to separate the electrochemical cells from each other is sufficiently contained so as not to alter the alignment of the components of the individual electrochemical cells and of the electrochemical cells with each other.

[0073] Preferably, arranging first foils of a first electrode precursor comprises arranging each first foil with a first surface and a second surface opposite the first surface.

[0074] Preferably, the first surface has a first active portion covered with active electrode material and a first electrical connection portion not covered with active electrode material.

[0075] Preferably, the second surface has a second active portion covered with active electrode material and a second electrical connection portion not covered with active electrode material. Preferably, the first active portion and the second active portion are identical to each other. Preferably, the second active portion and the first active portion are aligned with each other in a direction perpendicular to the first foil.

[0076] Preferably, the first electrical connection portion and the second electrical connection portion are identical to each other. Preferably, the second electrical connection portion and the first electrical connection portion are aligned with each other in a direction perpendicular to the first foil.

[0077] Preferably, the first active portion of each first foil is complementary to the first electrical connection portion of each first foil.

[0078] Preferably, the second active portion of each first foil is complementary to the second electrical connection portion of each first foil.

[0079] Similarly, preferably arranging second foils of a second electrode precursor comprises making each second foil with a first surface and a second surface opposite the first surface.

[0080] Preferably, the first surface has a first active portion covered with active electrode material and a first electrical connection portion not covered with active electrode material.

[0081] Preferably, the second surface has a second active portion covered with active electrode material and a second electrical connection portion not covered with active electrode material.

[0082] Preferably, the first active portion and the second active portion are identical to each other. Preferably, the second active portion and the first active portion are aligned with each other in a direction perpendicular to the second foil.

[0083] Preferably, the first electrical connection portion and the second electrical connection portion are identical to each other. Preferably, the second electrical connection portion and the first electrical connection portion are aligned with each other in a direction perpendicular to the first foil.

[0084] Preferably, the first active portion of each second foil is complementary to the first electrical connection portion of each second foil.

[0085] Preferably, the second active portion of each second foil is complementary to the second electrical connection portion of each second foil. Preferably, all the first foils have dimensions identical to each other.

[0086] Preferably, all the second foils have dimensions identical to each other.

[0087] Preferably, the first foils have identical dimensions to the second foils.

[0088] Preferably, all the first separator sheets have dimensions identical to each other.

[0089] Preferably, all the second separator sheets have dimensions identical to each other.

[0090] Preferably, the first separator sheets have dimensions identical to the second separator sheets.

[0091] Preferably, each first foil comprises a first free edge, a second free edge, a third free edge and a fourth free edge.

[0092] Preferably, each second foil comprises a first free edge, a second free edge, a third free edge and a fourth free edge.

[0093] Preferably, arranging, as coplanar to each other, said first foils comprises arranging a first foil placed in a row x of said N rows and placed in a column y of said M columns of said matrix pattern: with a first free edge adjacent to a first foil placed in the row x and placed in the column y-1 of said matrix pattern when y>1 or with said first free edge not adjacent to any first foil when y=1 ; with a second free edge adjacent to a first foil placed in the row x and placed in the column y+1 of said matrix pattern when y<M or with said first free edge not adjacent to any first foil when y=M; with a third free edge adjacent to a first foil placed in the row x-1 and placed in the column y of said matrix pattern when x>1 or with said third free edge not adjacent to any first foil when x=1 ; with a fourth free edge adjacent to a first foil placed in the row x+1 and placed in the column y of said matrix pattern when x<N or with said fourth free edge not adjacent to any first foil when x=N. x is comprised between 1 and N and indicates a row number within the matrix pattern with N rows and M columns. y is comprised between 1 and M and indicates a column number within the matrix pattern with N rows and M columns. Preferably, arranging, as coplanar to each other, said second foils comprises arranging a second foil placed in a row x of said N rows and placed in a column y of said M columns of said matrix pattern: with a first free edge adjacent to a second foil placed in the row x and placed in the column y-1 of said matrix pattern when y>1 or with said first free edge not adjacent to any second foil when y=1 ; with a second free edge adjacent to a second foil placed in the row x and placed in the column y+1 of said matrix pattern when y<M or with said first free edge not adjacent to any second foil when y=M; with a third free edge adjacent to a second foil placed in the row x-1 and placed in the column y of said matrix pattern when x>1 or with said third free edge not adjacent to any second foil when x=1 ; with a fourth free edge adjacent to a second foil placed in the row x+1 and placed in the column y of said matrix pattern when x<N or with said fourth free edge not adjacent to any second foil when x=N.

[0094] Preferably, arranging, as coplanar to each other, said first separator sheets comprises arranging a first separator sheet placed in a row x of said N rows and placed in a column y of said M columns of said matrix pattern: with a first edge adjacent to a first separator sheet placed in the row x and placed in the column y-1 of said matrix pattern when y>1 or with said first edge not adjacent to any first separator sheet when y=1 ; with a second edge adjacent to a first separator sheet placed in the row x and placed in the column y+1 of said matrix pattern when y<M or with said first edge not adjacent to any first separator sheet when y=M; with a third edge adjacent to a first separator sheet placed in the row x-1 and placed in the column y of said matrix pattern when x>1 or with said third edge not adjacent to any first separator sheet when x=1 ; with a fourth edge adjacent to a first separator sheet placed in the row x+1 and placed in the column y of said matrix pattern when x<N or with said fourth edge not adjacent to any first separator sheet when x=N.

[0095] Preferably, arranging, as coplanar to each other, said second separator sheets comprises arranging a second separator sheet placed in a row x of said N rows and placed in a column y of said M columns of said matrix pattern: with a first edge adjacent to a second separator sheet placed in the row x and placed in the column y-1 of said matrix pattern when y>1 or with said first edge not adjacent to any second separator sheet when y=1 ; with a second edge adjacent to a second separator sheet placed in the row x and placed in the column y+1 of said matrix pattern when y<M or with said first edge not adjacent to any second separator sheet when y=M; with a third edge adjacent to a second separator sheet placed in the row x- 1 and placed in the column y of said matrix pattern when x>1 or with said third edge not adjacent to any second separator sheet when x=1 ; with a fourth edge adjacent to a second separator sheet placed in the row x+1 and placed in the column y of said matrix pattern when x<N or with said fourth edge not adjacent to any second separator sheet when x=N.

[0096] Preferably, the first electrical connection portion of each first foil develops starting from the first free edge of each first foil towards the second free edge.

[0097] Preferably, the second electrical connection portion of each first foil develops starting from the first free edge of each first foil towards the second free edge.

[0098] Preferably, the first electrical connection portion of each second foil develops starting from the second free edge of each second foil towards the first free edge.

[0099] Preferably, the second electrical connection portion of each second foil develops starting from the second free edge of each second foil towards the first free edge.

[0100] When said first separator sheets, said first foils, said second separator sheets and said second foils are stacked on each other, the electrical connection portions of first foils of a stacking group are not overlapped on the electrical connection portions of second foils of the same stacking group.

[0101] When said first separator sheets, said first foils, said second separator sheets and said second foils are stacked on each other, the electrical connection portions of all the first foils of a same stacking group are overlapped on each other.

[0102] When said first separator sheets, said first foils, said second separator sheets and said second foils are stacked on each other, the electrical connection portions of all the second foils of a same stacking group are overlapped on each other.

[0103] In a first embodiment, preferably the first electrical connection portion of each first foil further develops starting from the fourth free edge of each first foil towards the third free edge. In this embodiment, preferably the second electrical connection portion of each first foil further develops starting from the fourth free edge of each first foil towards the third free edge.

[0104] In this embodiment, preferably the first electrical connection portion of each second foil further develops starting from the third free edge of each first foil towards the fourth free edge.

[0105] In this embodiment, preferably the second electrical connection portion of each second foil further develops starting from the third free edge of each first foil towards the fourth free edge.

[0106] In a second embodiment, preferably the first electrical connection portion of each first foil develops only starting from the first free edge of each first foil towards the second free edge.

[0107] In this embodiment, preferably the second electrical connection portion of each first foil develops only starting from the first free edge of each first foil towards the second free edge.

[0108] In this embodiment, preferably the first electrical connection portion of each second foil develops only starting from the second free edge of each first foil towards the first free edge.

[0109] In this embodiment, preferably the second electrical connection portion of each second foil develops only starting from the second free edge of each first foil towards the first free edge.

[0110] In both embodiments, by overlapping the first active portion of the first surface of a second foil on the second active portion of the second surface of a first foil, the electrical connection portions of the first foil are not overlapped on the electrical connection portions of the second foil.

[0111] Preferably, laying the first foils on top of the first separator sheets comprises overlapping the first active portion of each first foil on a respective first separator sheet. Preferably, the first active portion of each first foil is completely overlapped on a respective first separator sheet. Preferably, the first active portion of each first foil is in direct contact with a respective first separator sheet.

[0112] Further, preferably laying the second separator sheets on top of the first foils comprises overlapping each second separator sheet on the second active portion of a respective first foil. Preferably, each second separator sheet completely covers the second active portion of a respective first foil. Preferably, each second separator sheet is in direct contact with the second active portion of a respective first foil.

[0113] Further, preferably laying the second foils on top of the second separator sheets comprises overlapping the first active portion of each second foil on a respective second separator sheet. Preferably, the first active portion of each second foil is completely overlapped on a respective second separator sheet. Preferably, the first active portion of each second foil is in direct contact with a respective second separator sheet.

[0114] The Applicant has verified that in this way the active portions of two foils of electrode precursor are never in contact with each other but are always completely separated by a respective separator sheet.

[0115] Preferably, transferring simultaneously all the first separator sheets to the stacking station and transferring simultaneously all the second separator sheets to the stacking station is implemented by arranging the second separator sheets completely overlapped on the first separator sheets, wherein first foils are interposed between the first separator sheets and the second separator sheets.

[0116] Preferably, transferring simultaneously all the first separator sheets to the stacking station, transferring simultaneously all the first foils to the stacking station, transferring simultaneously all the second separator sheets to the stacking station, and transferring simultaneously all the first foils to the stacking station is implemented by laying the first foils offset relative to the respective first separator sheets and by laying the second foils offset relative to the second separator sheets.

[0117] In this way, it is possible to ensure that the free edges of the first and second foils from which the respective active portions develop can never come into mutual contact, as the offset between the first and second foils and first and second separator sheets is such that the first and second separator sheet extend beyond the free edges of the first and second foils from which the respective active portions develop. In other words, this offset is such that the free edges of the first and second foils from which the respective active portions develop are positioned between two free edges of the first and second separator sheets.

[0118] In the first embodiment, preferably laying the first foils offset relative to the respective first separator sheets is implemented such that both the rows of first foils and the columns of first foils are offset relative to the respective rows and columns of the first separator sheets.

[0119] In this embodiment, preferably laying the second foils offset relative to the respective second separator sheets is implemented such that both the rows of second foils and the columns of second foils are offset relative to the respective rows and columns of the second separator sheets.

[0120] In the second embodiment, preferably laying the first foils offset relative to the respective first separator sheets is implemented such that only the rows or only the columns of first foils are offset relative to the respective rows and columns of the first separator sheets.

[0121] In this embodiment, preferably laying the second foils offset relative to the respective second separator sheets is implemented such that only the rows or only the columns of the second foils are offset relative to the respective rows and columns of the second separator sheets.

[0122] Preferably, laying the first foils on top of the first separator sheets comprises arranging the first electrical connection portion of a first foil at least partially cantilevered relative to said first separator sheet on which the first active portion of the first foil is overlapped. Preferably, the cantilevered portion of the first electrical connection portion of a first foil is not in direct contact with said first separator sheet on which the first active portion of the first foil is overlapped.

[0123] Preferably, laying the second foils on top of the second separator sheets comprises arranging the first electrical connection portion of a second foil at least partially cantilevered relative to said second separator sheet on which the first active portion of the second foil is overlapped. Preferably, the cantilevered portion of the first electrical connection portion of a second foil is not in direct contact with said second separator sheet on which the first active portion of the second foil is overlapped.

[0124] The Applicant has verified that in this way at least a part of each electrical connection portion of the electrode precursor foils is not overlapped on the separator sheets. In this way, it is possible, for each electrochemical cell, to electrically connect together the electrical connection portions of the first foils and the electrical connection portions of the second foils and to ensure the formation of two electrical poles in the battery that will be formed. The Applicant has also verified that by laying the first foils offset relative to the respective first separator sheets and by laying the second foils offset relative to the second separator sheets, it is possible to arrange at least partially cantilevered both the first electrical connection portion of each first foil relative to said first separator sheet on which the first active portion of the first foil is overlapped and the first electrical connection portion of each second foil relative to said second separator sheet on which the first active portion of the second foil is overlapped.

[0125] Preferably, the cantilevered portion of the first electrical connection portion of a first foil projects from a free edge of the respective first separator sheet opposite relative to the free edge of the second separator sheet from which the cantilevered portion of the first electrical connection portion of the second foil projects.

[0126] In the first embodiment, preferably the cantilevered portion of the first electrical connection portion of a first foil projects from two free edges (preferably the first and fourth free edge) of said first separator sheet on which the first active portion of the first foil is overlapped.

[0127] In this embodiment, preferably the cantilevered portion of the first electrical connection portion of a second foil projects from two free edges (preferably the second and third free edge) of said second separator sheet on which the second active portion of the second foil is overlapped.

[0128] In the second embodiment, preferably the cantilevered portion of the first electrical connection portion of a first foil projects from a single free edge (preferably the first free edge) of said first separator sheet on which the first active portion of the first foil is overlapped.

[0129] In this embodiment, preferably the cantilevered portion of the first electrical connection portion of a second foil projects from a single free edge (preferably the second free edge) of said second separator sheet on which the second active portion of the second foil is overlapped.

[0130] As mentioned, it is preferable to prevent the various components of the individual electrochemical cells from moving relative to each other once the first foils, the second foils, the first separator sheets and the second separator sheets are stacked on each other in the stacking station. In this regard, preferably, laying the first foils on top of the first separator sheets comprises overlapping a portion of the first electrical connection portion of each first foil on a first separator sheet adjacent to said first separator sheet on which the first active portion of the first foil is overlapped.

[0131] In other words, preferably a portion of the first connection portion of the first foil of a stacking group is overlapped on the first separator sheet of another stacking group, in particular of an adjacent stacking group.

[0132] The Applicant has verified that this makes it possible to make the matrix pattern of the stacking groups more stable, i.e. it tends to prevent the various stacking groups from being able to move relative to each other in the stacking station. The Applicant considers that this is very advantageous when electrochemical cells having a plurality of stacking groups overlapped on each other are made in the stacking station. The Applicant has indeed noted that as the electrochemical cells being formed in the stacking station develop in height, their stability tends to decrease. The fact that a portion of the first connection portion of a stacking group is overlapped on the first separator sheet of another stacking group, realizes a sort of interlocking between the stacking groups which, as mentioned, makes the matrix pattern with the stacking groups more stable.

[0133] Alternatively or in combination with overlapping a portion of the first electrical connection portion of each first foil on a first separator sheet adjacent to said first separator sheet on which the first active portion of the first foil is overlapped, it is provided that laying the second foils on top of the second separator sheets comprises overlapping a portion of the first electrical connection portion of each second foil on a second separator sheet adjacent to said second separator sheet on which the first active portion of the second foil is overlapped.

[0134] In other words, preferably a portion of the first connection portion of the second foil of a stacking group is overlapped on the second separator sheet of another stacking group, in particular of an adjacent stacking group.

[0135] In the first embodiment, preferably a portion of the first connection portion of the first foil of a stacking group is overlapped both on the first separator sheet of a first further stacking group and on the first separator sheet of a second further stacking group. Preferably, said first further stacking group and said second further stacking group belong to two adjacent rows and two adjacent columns within the matrix pattern of stacking groups. In this embodiment, preferably a portion of the first connection portion of the second foil of a stacking group is overlapped both on the first separator sheet of a third further stacking group and on the first separator sheet of a fourth further stacking group. Preferably, said third further stacking group and said fourth further stacking group belong to two adjacent rows and two adjacent columns within the matrix pattern of stacking groups.

[0136] In the second embodiment, preferably a portion of the first connection portion of the first foil of a stacking group is overlapped on the first separator sheet of a single first further stacking group.

[0137] In this embodiment, preferably a portion of the first connection portion of the second foil of a stacking group is overlapped on the second separator sheet of a single third further stacking group.

[0138] Preferably, the first further stacking group and the third further stacking group belong to the same row and are arranged on the opposite side relative to the stacking group on which the first foil and the second foil are mainly laid.

[0139] Preferably, arranging first foils of a first electrode precursor comprises feeding along a first plane a piece of strip of first electrode precursor and making longitudinal notches and transverse notches in said piece of strip of first electrode precursor to define said matrix pattern with N rows of first foils and M columns of first foils.

[0140] In this way, from a single piece of strip of the first electrode precursor, the first foils are made physically separated from each other by said notches.

[0141] Preferably, feeding along the first plane a piece of strip of first electrode precursor comprises arranging said piece of strip of first electrode precursor with first active portions and with second active portions aligned along N rows and M columns.

[0142] Said first active portions and said second active portions are the active portions of the first foils when said longitudinal notches and transverse notches are made.

[0143] In the first embodiment, preferably, arranging said piece of strip of first electrode precursor with first active portions and with second active portions aligned along N rows and M columns comprises arranging said piece of strip of first electrode precursor with said first active portions spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows and with said second active portions spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows.

[0144] In the second embodiment, preferably, arranging said piece of strip of first electrode precursor with first active portions and with second active portions aligned along N rows and M columns comprises arranging said piece of strip of first electrode precursor with said first active portions spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows and with said second active portions spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows.

[0145] Preferably, arranging second foils of a second electrode precursor comprises feeding along a second plane a piece of strip of second electrode precursor and making longitudinal notches and transverse notches in said piece of strip of second electrode precursor to define said matrix pattern with N rows of second foils and M columns of second foils.

[0146] In this way, from a single piece of strip of the second electrode precursor, the second foils are made physically separated from each other by said notches.

[0147] Preferably, feeding along a second plane a piece of strip of second electrode precursor comprises arranging said piece of strip of second electrode precursor with first active portions and with second active portions aligned along N rows and M columns.

[0148] Said first active portions and said second active portions are the active portions of the second foils when said longitudinal notches and transverse notches are made.

[0149] In the first embodiment, preferably, arranging said piece of strip of second electrode precursor with first active portions and with second active portions aligned along N rows and M columns comprises arranging said piece of strip of second electrode precursor with said first active portions spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows and with said second active portions spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows.

[0150] In the second embodiment, preferably, providing said piece of strip of second electrode precursor with first active portions and with second active portions aligned along N rows and M columns comprises providing said piece of strip of second electrode precursor with said first active portions spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows and with said second active portions spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows.

[0151] Preferably, the apparatus comprises cutting members placed at the first plane to operate on first pieces of strip of first electrode precursor and make the first foils and placed at the second plane to operate on second pieces of strip of second electrode precursor and make the second foils.

[0152] Preferably, said cutting members comprise at least a laser cutting device or at least a cutting blade.

[0153] Preferably, the first plane and the second plane are physically distinct from each other and placed at the stacking station.

[0154] In this case, the cutting members operating on the first pieces of strip of first electrode precursor are physically distinct from the cutting members operating on the second pieces of strip of second electrode precursor.

[0155] Preferably, making longitudinal notches and transverse notches in said piece of strip of first electrode precursor can be implemented simultaneously with making longitudinal notches and transverse notches in said piece of strip of second electrode precursor.

[0156] Preferably, arranging, as coplanar to each other, first separator sheets comprises feeding along a separator plane a first piece of separator strip and making longitudinal incisions and transverse incisions in said first piece of separator strip to define said matrix pattern with N rows of first separator sheets and M columns of first separator sheets.

[0157] Preferably, these incisions create pre-weakening lines that may possibly alternate with cutting lines.

[0158] In this way, from a single piece of separator strip the first separator sheets are made physically joined together by pre-weakening lines.

[0159] Alternatively, such incisions make only cutting lines.

[0160] In this case, from a single piece of separator strip the first sheets are made physically separated from each other by notches. Preferably, arranging, as coplanar to each other, second separator sheets comprises feeding along said separator plane a second piece of separator strip and making longitudinal incisions and transverse incisions in said second piece of separator strip to define said matrix pattern with N rows of second separator sheets and M columns of second separator sheets.

[0161] Preferably, these incisions create pre-weakening lines that may possibly alternate with cutting lines.

[0162] In this way, from a single piece of separator strip the second separator sheets are made physically joined together by pre-weakening lines.

[0163] Alternatively, such incisions make only cutting lines.

[0164] In this case, from a single piece of separator strip the second sheets are made physically separated from each other by notches.

[0165] Preferably, said apparatus comprises cutting members placed at the separator plane and respectively configured to operate on first pieces of separator strip and on second pieces of separator strip to make said first separator sheets and said second separator sheets.

[0166] Preferably, the separator plane is a single plane and is placed at the stacking station.

[0167] The cutting members operating on the first pieces of separator coincide with the cutting members operating on the second pieces of separator strip.

[0168] Preferably, feeding along said separator plane a second piece of separator strip is implemented after transferring all the first separator sheets to the stacking station.

[0169] This allows a single separator plane to be used to make both the first separator sheets and the second separator sheets.

[0170] Preferably, transferring simultaneously all the first foils to the stacking station comprises withdrawing simultaneously all the first foils from the first plane and releasing simultaneously all the first foils in the stacking station.

[0171] In this way, in a single action all the first foils are transferred to the stacking station. This action is carried out by the transfer members which withdraw simultaneously all the first foils and release them simultaneously in the stacking station.

[0172] Preferably, transferring simultaneously all the second foils to the stacking station comprises withdrawing simultaneously all the second foils from the second plane and releasing simultaneously all the second foils in the stacking station.

[0173] In this way, in a single action all the second foils are transferred to the stacking station.

[0174] This action is carried out by the transfer members which withdraw simultaneously all the second foils and release them simultaneously in the stacking station.

[0175] Preferably, transferring simultaneously all the first separator sheets to the stacking station comprises withdrawing simultaneously all the first separator sheets from the separator plane and releasing simultaneously all the first separator sheets to the stacking station.

[0176] In this way, in a single action all the first separator sheets are transferred to the stacking station.

[0177] This action is carried out by the transferring members which withdraw simultaneously all the first separator sheets and release them simultaneously in the stacking station.

[0178] Preferably, transferring simultaneously all the second separator sheets to the stacking station comprises withdrawing simultaneously all the second separator sheets from the separator plane and releasing simultaneously all the second separator sheets to the stacking station.

[0179] In this way, in a single action all the second separator sheets are transferred to the stacking station.

[0180] This action is carried out by the transfer members which withdraw simultaneously all the second separator sheets and release them simultaneously in the stacking station.

[0181] In the second embodiment, preferably transferring simultaneously all the first foils to the stacking station further comprises moving the rows of the first foils away from each other after withdrawing simultaneously all the first foils from the first plane and before releasing simultaneously all the first foils in the stacking station. For this purpose, preferably said N rows of retaining elements are movable between a moved-closer condition and a moved-away condition.

[0182] Preferably, in said moved-away condition the distance between adjacent rows of retaining elements is greater than the distance between adjacent rows of retaining elements in said moved-closer condition.

[0183] In this embodiment, moving the rows of first foils away allows moving away from each other, in the stacking station, the first active portions and the second active portions of a first foil from the first active portions and from the second active portions of the adjacent first foils in the same row. In this way, it can be ensured that the first active portions and the second active portions of the first foils are completely covered with respective first and second separator sheets.

[0184] In fact, in this embodiment, the first foils have a transverse extension (understood as an extension between the third and fourth free edge) that is preferably less than the transverse extension of the first separator sheets and of the second separator sheets.

[0185] In this embodiment, preferably releasing all the first foils in the stacking station comprises positioning each first foil in a centred position (preferably in a transverse direction) on a respective first separator sheet.

[0186] Preferably, moving the rows of first foils away from each other is implemented without releasing the first foils.

[0187] Preferably, moving the rows of first foils away from each other is implemented during the transfer of the first foils from the first plane to the stacking station.

[0188] In the second embodiment, preferably transferring simultaneously all the second foils to the stacking station further comprises moving the rows of second foils away from each other after withdrawing simultaneously all the second foils from the second plane and before releasing simultaneously all the second foils in the stacking station.

[0189] For this purpose, preferably said N rows of retaining elements are movable between a moved-closer condition and a moved-away condition.

[0190] Preferably, in said moved-away condition the distance between adjacent rows of retaining elements is greater than the distance between adjacent rows of retaining elements in said moved-closer condition. In this embodiment, moving the rows of second foils away allows moving away from each other, in the stacking station, the first active portions and the second active portions of a second foil from the first active portions and from the second active portions of the adjacent second foils in the same row. In this way, it can be ensured that the first active portions and the second active portions of the second foils are completely covered with respective first and second separator sheets.

[0191] In fact, in this embodiment, the second foils have a transverse extension (understood as an extension between the third and fourth free edge) that is preferably less than the transverse extension of the first separator sheets and of the second separator sheets.

[0192] In this embodiment, preferably releasing all the second foils in the stacking station comprises positioning each second foil in a centred position (preferably in a transverse direction) on a respective second separator sheet.

[0193] Preferably, moving the rows of second foils away from each other is implemented without releasing the second foils.

[0194] Preferably, moving the rows of second foils away from each other is implemented during the transfer of the second foils from the second plane to the stacking station.

[0195] In both embodiments it is preferably provided for pressing the stacking groups made.

[0196] In both embodiments it is preferably provided, after having formed the stacking groups, to perform actions on the stacking groups.

[0197] Preferably, said further actions comprise pressing the stacking groups and moving the stacking groups.

[0198] Preferably, pressing the stacking groups precedes moving the stacking groups.

[0199] Preferably, an active press is provided at the stacking station configured to press the stacking groups.

[0200] Further characteristics and advantages of the present invention will become clearer from the following detailed description of some preferred embodiments, with reference to the appended drawings and provided by way of indicative and non-limiting example, in which: figure 1 is a schematic top view of an apparatus for making electrochemical cells in accordance with the present invention; figure 2 is a schematic side view of a detail of the apparatus of figure 1 ; figure 3 is a schematic side view of a transfer member of the apparatus of figure 1 ; figure 4 is a schematic side view of two stacking groups made by the apparatus of figure 1 ; figure 5 is a schematic side view of a portion of the stacking groups of figure 4; figures 6 and 7 are schematic top views of a first embodiment of electrode precursor foils used in the apparatus of figure 1 ; figures 8A and 8B are schematic top views of stacking groups being formed made by the apparatus of figure 1 using electrode precursor foils of figure 6 and 7; figures 9 and 10 are schematic top views of a second embodiment of electrode precursor foils used in the apparatus of figure 1 ; figures 11A and 11 B are schematic top views of stacking groups being formed made by the apparatus of figure 1 using electrode precursor foils of figure 9 and 10; and figures 12 and 13 are schematic top views of separator sheets used in the apparatus of figure 1 .

[0201] The representations in the appended figures must not be understood in scale, do not necessarily respect the proportions between the various parts and must be understood as diagrams.

[0202] With reference to figure 1 , an apparatus for making electrochemical cells in accordance with the present invention is indicated overall with 10.

[0203] The apparatus 10 is configured to implement a method for making electrochemical cells in accordance with the present invention.

[0204] This method provides for arranging first foils 100 of a first electrode precursor in such a way that said first foils 100 are arranged coplanar to each other and according to a matrix pattern in which the first foils 100 are arranged in N rows and M columns, as schematically illustrated in figures 6 and 9. In these figures, the rows are indicated with the reference R and the columns are indicated with the reference C.

[0205] Four rows and four columns have been represented in these figures for exhibition needs. However, the number N of rows and the number M of columns may be substantially any, preferably N is greater than or equal to 2 and M is greater than or equal to 2. figure 6 schematically represents a first embodiment of the first foils 100 and figure 9 represents a second embodiment of the first foils 100. The following applies identically to both embodiments except for some differences that will be expressly indicated.

[0206] Each first foil 100 is physically separated from the other first foils 100.

[0207] Each first foil 100 is quadrangular in shape and comprises four free edges 101. The second foils 110 all have the same shape and dimension. In particular, each first foil 100 comprises a first free edge 101 a, a second free edge 101 b opposite the first free edge 101 a, a third free edge 101 c placed between the first free edge 101 a and the second free edge 101 b and a fourth free edge 101d opposite the third free edge 101 c.

[0208] The first foils 100 are arranged in said matrix pattern with the first free edge 101a of a first foil 100 adjacent to the second free edge 101 b of a further first foil 100 placed in the same row and with the third free edge 101 c of a first foil 100 adjacent to the fourth free edge 101 c of a further first foil 100 placed in the same column, as schematically illustrated in figures 6 and 9.

[0209] Each first foil 100 comprises a first surface 102 and a second surface 103 opposite the first surface 102. In figures 6 and 9, being seen from above the first foils 100, the only second surfaces 103 of the first foils 100 are represented. In figure 5, both the first surface 102 and the second surface 103 of a first foil 100 are visible in side view.

[0210] The first surface 102 comprises a first active portion 104 covered with active electrode material. The first active portion 104 develops starting from the second free edge 101 b toward the first free edge 101 a and does not reach the first free edge 101 a. The first active portion 104 further develops from the third free edge 101 c toward the fourth free edge 101 d. Similarly, the second surface 103 comprises a second active portion 105 covered with active electrode material. The second active portion 105 develops starting from the second free edge 101 b toward the first free edge 101 a and does not reach the first free edge 101 a. The second active portion 105 further develops starting from the third free edge 101 c towards the fourth free edge 101 d. The first active portion 104 is exactly overlapped, in a direction perpendicular to the first surface 102 and to the second surface 103, on the second active portion 105. The active electrode material may be an anode or cathode material (depending on the material from which the first electrode precursor foils are made) and may comprise, in the case of anode material, graphite or other carbonaceous materials or silicon-based materials and, in the case of cathode material, lithium oxide, nickel, manganese, cobalt, aluminium or lithium and iron phosphate-based materials.

[0211] The first surface 102 further comprises a first electrical connection portion 106 not covered with active electrode material. The first electrical connection portion 106 is complementary to the first active portion 104. The first electrical connection portion 106 develops starting from the first free edge 101 a and reaches the first active portion 104. Similarly, the second surface 103 further comprises a second electrical connection portion 107 not covered with active electrode material. The second electrical connection portion 107 is complementary to the second active portion 105. The second electrical connection portion 107 develops starting from the first free edge 101 a and reaches the second active portion 104. The first electrical connection portion 106 is exactly overlapped, in a direction perpendicular to the first surface 102 and to the second surface 103, on the second electrical connection portion 107.

[0212] In the embodiment of figure 6, the first active portion 104 does not reach the fourth free edge 101 d and the first electrical connection portion 106 further develops starting from the fourth free edge 101 d until it reaches the first active portion 104. In this embodiment, the second active portion 105 does not reach the fourth free edge 101 d and the second electrical connection portion 107 further develops starting from the fourth free edge 101 d until it reaches the second active portion 105.

[0213] In the embodiment of figure 9, the first active portion 104 reaches the fourth free edge 101 d. In this embodiment, the second active portion 105 reaches the fourth free edge 101 d. The method of the present invention further provides for arranging second foils 110 of a second electrode precursor such that said second foils 110 are arranged coplanar to each other and according to a matrix pattern in which the second foils 110 are arranged in N rows and M columns, as schematically illustrated in figure 7 and 10. In these figures, the rows are indicated with the reference R and the columns are indicated with the reference C.

[0214] Four rows and four columns have been represented in these figures for exhibition needs. However, the number N of rows and the number M of columns may be substantially any, preferably N is greater than or equal to 2 and M is greater than or equal to 2.

[0215] In any case, the number of rows of the first foils 100 is equal to the number of rows of the second foils 110 and the number of columns of the first foils 100 is equal to the number of columns of the second foils 110. figure 7 schematically represents a first embodiment of the second foils 110 and figure 10 represents a second embodiment of the second foils 110. The following applies identically to both embodiments except for some differences that will be expressly indicated.

[0216] Each second foil 110 is physically separated from the other second foils 110.

[0217] Each second foil 110 is quadrangular in shape and comprises four free edges 111. The second foils 110 all have the same shape and dimension. The shape and dimension of the second foils 110 is the same as the shape and dimension of the first foils 100. In particular, each second foil 110 comprises a first free edge 111 a, a second free edge 111 b opposite the first free edge 111a, a third free edge 111 c placed between the first free edge 111 a and the second free edge 111 b and a fourth free edge 111 d opposite the third free edge 111 c.

[0218] The second foils 110 are arranged in said matrix pattern with the first free edge 111 a of a second foil 110 adjacent to the second free edge 111 b of a further second foil 110 placed in the same row and with the third free edge 111 c of a second foil 110 adjacent to the fourth free edge 111 c of a further second foil 110 placed in the same column, as schematically illustrated in figure 7 and 10.

[0219] Each second foil 110 comprises a first surface 112 and a second surface 113 opposite the first surface 112. In figures 7 and 10, being seen from above the second foils 110, the only second surfaces 113 of the second foils 110 are represented. In figure 5, both the first surface 112 and the second surface 113 of a second foil 110 are visible in side view.

[0220] The first surface 112 comprises a first active portion 114 covered with active electrode material. The first active portion 114 develops starting from the first free edge 111 a toward the second free edge 111 b and does not reach the second free edge 111 b. The first active portion 114 further develops starting from the fourth free edge 111 d toward the third free edge 111 c. Similarly, the second surface 113 comprises a second active portion 115 covered with active electrode material. The second active portion 115 develops starting from the first free edge 101 a toward the second free edge 101 b and does not reach the second free edge 101 b. The second active portion 115 further develops starting from the fourth free edge 101 d towards the third free edge 101 c. The first active portion 114 is exactly overlapped, in a direction perpendicular to the first surface 112 and to the second surface 113, on the second active portion 115. The active electrode material may be an anode or cathode material (depending on the material from which the second electrode precursor foils are made) and may comprise, in the case of anode material, graphite or other carbonaceous materials or silicon-based materials and, in the case of cathode material, lithium oxide, nickel, manganese, cobalt, aluminium or lithium and iron phosphate-based materials. When the first foils 100 have portions covered with anode material, the second foils 110 have portions covered with cathode material and when the first foils 100 have portions covered with cathode material, the second foils 110 have portions covered with anode material.

[0221] The first surface 112 further comprises a first electrical connection portion 116 not covered with active electrode material. The first electrical connection portion 116 is complementary to the first active portion 114. The first electrical connection portion 116 develops starting from the second free edge 101 b and reaches the first active portion 114. Similarly, the second surface 113 further comprises a second electrical connection portion 117 not covered with active electrode material. The second electrical connection portion 117 is complementary to the second active portion 115. The second electrical connection portion 117 develops starting from the second free edge 101 b and reaches the second active portion 114. The first electrical connection portion 116 is exactly overlapped, in a direction perpendicular to the first surface 112 and to the second surface 113, on the second electrical connection portion 117.

[0222] In the embodiment of figure 7, the first active portion 114 does not reach the third free edge 111c and the first electrical connection portion 116 also develops starting from the third free edge 111 c until it reaches the first active portion 114. In this embodiment, the second active portion 1 15 does not reach the third free edge 111 c and the second electrical connection portion 117 further develops starting from the third free edge 111 c until it reaches the second active portion 115.

[0223] In the embodiment of figure 10, the first active portion 114 reaches the third free edge 111 c. In this embodiment, the second active portion 115 reaches the third free edge 111c.

[0224] The method of the present invention further provides for arranging first separator sheets 120 such that said first separator sheets 120 are arranged coplanar to each other and according to a matrix pattern in which the first separator sheets 120 are arranged in N rows and M columns, as schematically illustrated in figure 12. In this figure, the rows are indicated with the reference R and the columns are indicated with the reference C.

[0225] Four rows and four columns have been represented in figure 12 for exhibition needs. However, the number N of rows and the number M of columns may be substantially any, preferably N is greater than or equal to 2 and M is greater than or equal to 2.

[0226] In any case, the number of rows of the first separator sheets 120 is equal to the number of rows of the first foils 100 and the number of columns of the first separator sheets 120 is equal to the number of columns of the first foils 100.

[0227] The first separator sheets 120 are made of dielectric material.

[0228] In the preferred embodiment of the invention, each first separator sheet 120 is physically connected to adjacent first separator sheets 120 by pre-weakening lines 121.

[0229] Each first separator sheet 120 is quadrangular in shape and comprises four free edges 122. The first separator sheets 120 all have the same shape and dimension. Each first separator sheet 120 comprises a first edge 121 a, a second edge 121 b opposite the first edge 121 a, a third edge 121c placed between the first edge 121 a and the second edge 121 b and a fourth edge 121 d opposite the third edge 121 c. In the first embodiment of the first foils 110 and of the second foils 110, the first separator sheets 120 have dimensions equal to the first foils 100 and to the second foils 110. In the second embodiment of the first foils 110 and of the second foils 110, the first separator sheets 120 have dimensions greater than the first foils 100 and the second foils 110. In particular, the distance between the third free edge 111 c and the fourth free edge 111 d of the first foils 100 and the second foils 110 is smaller than the distance between the third edge 121 d and the fourth edge 121 d of the first separator sheets 120.

[0230] The first separator sheets 120 are arranged in said matrix pattern with the first edge 121 a of a first separator sheet 120 adjacent to the second edge 121 b of a further first separator sheet 120 placed in the same row and with the third edge 121 c of a first separator sheet 120 adjacent to the fourth edge 121 c of a further first separator sheet 120 placed in the same column, as schematically illustrated in figure 12.

[0231] The method of the present invention further provides for arranging second separator sheets 130 such that said second separator sheets 130 are arranged coplanar to each other and according to a matrix pattern in which the second separator sheets 130 are arranged in N rows and M columns, as schematically illustrated in figure 13. In this figure, the rows are indicated with the reference R and the columns are indicated with the reference C.

[0232] Four rows and four columns have been represented in figure 13 for exhibition needs. However, the number N of rows and the number M of columns may be substantially any, preferably N is greater than or equal to 2 and M is greater than or equal to 2.

[0233] In any case, the number of rows of the second separator sheets 130 is equal to the number of rows of the first foils 100 and the number of columns of the second separator sheets 130 is equal to the number of columns of the first foils 100.

[0234] The second separator sheets 130 are made of dielectric material.

[0235] In the preferred embodiment of the invention, each second separator sheet 130 is physically connected to adjacent second separator sheets 130 by preweakening lines 132.

[0236] Each second separator sheet 130 is quadrangular in shape and comprises four free edges 131 . The second separator sheets 130 all have the same shape and dimension. The shape and dimension of the second separator sheets 130 is the same as the shape and dimension of the first separator sheets 120. In particular, each second separator sheet 130 comprises a first edge 131 a, a second edge 131 b opposite the first edge 131 a, a third edge 131c placed between the first edge 131 a and the second edge 131 b and a fourth edge 131 d opposite the third edge 131 c.

[0237] The second separator sheets 130 are arranged in said matrix pattern with the first edge 131 a of a second separator sheet 130 adjacent to the second edge 131 b of a further second separator sheet 130 placed in the same row and with the third edge 131 c of a second separator sheet 130 adjacent to the fourth edge 131 c of a further fourth separator sheet 130 placed in the same column, as schematically illustrated in figure 13.

[0238] To arrange the first foils 100 coplanar to each other and according to the matrix pattern with N rows and M columns, the apparatus 10 comprises a first plane 11 on which a piece of strip of first electrode precursor is fed from a continuous coil 108 of first electrode precursor, as schematically illustrated in figure 1 . At the first plane 11 , and in particular in elevation relative to the first plane 11 , the apparatus 10 comprises cutting members 12 that are configured to cut the first foils 100 from the piece of first electrode precursor. These cutting members 12 comprise, in the preferred embodiment of the invention, at least a first laser cutting device 13. By way of example, the first laser cutting device 13 comprises a laser oscillator that emits a laser bundle and a galvanometric scanner configured to move the focal point of the laser bundle and focus it in a desired position along the first plane 11 and on the piece of first electrode precursor.

[0239] The first laser cutting device 13 executes longitudinal (through) notches and transverse (through) notches in the piece of strip of first electrode precursor, separating the first electrode precursor in said first foils 100 arranged according to the matrix pattern with N rows and M columns, as schematically indicated in figure 1. The first foils 100 thus made remain resting on the first plane 11 maintaining the arrangement according to the matrix pattern thus made. The first continuous electrode precursor wound on the coil 108 already carries the first active portions 104 and the second active portions 105. Alternatively, the first active portions 104 and the second active portions 105 are deposited on the piece of strip of first electrode precursor before the first foils 100 are cut therefrom.

[0240] To arrange the second foils 110 coplanar to each other and according to the matrix pattern with N rows and M columns, the apparatus 10 comprises a second plane 14 on which a piece of strip of second electrode precursor is fed from a continuous coil 118 of second electrode precursor, as schematically illustrated in figure 1 . The cutting members 12 are also provided at the second plane 14, and in particular in elevation relative to the first plane 14, and are configured to cut the second foils 110 from the piece of second electrode precursor. The cutting members 12 comprise, in the preferred embodiment of the invention, at least a second laser cutting device 15. By way of example, the second laser cutting device 15 may be structurally and functionally identical to the first laser cutting device 13, although physically distinct from the latter.

[0241] The second laser cutting device 15 executes longitudinal (through) notches and transverse (through) notches in the piece of strip of second electrode precursor, separating the second electrode precursor in said second foils 110 arranged according to the matrix pattern with N rows and M columns, as schematically indicated in figure 1. The second foils 110 thus made remain resting on the second plane 14 maintaining the arrangement according to the matrix pattern thus made. The second continuous electrode precursor wound on the coil 118 already carries the first active portions 114 and the second active portions 115. Alternatively, the first active portions 114 and the second active portions 115 are deposited on the piece of strip of second electrode precursor before the second foils 110 are cut therefrom.

[0242] To arrange the first separator sheets 120 coplanar to each other and according to the matrix pattern with N rows and M columns, the apparatus 10 comprises a separator plane 16 on which a piece of separator strip is fed from a continuous coil 123 of separator strip, as schematically illustrated in figure 1. The cutting members 12 are also provided at the separator plane 16, and in particular in elevation relative to the separator plane 16, and are configured to score the preweakening lines 122 on the piece of separator strip and thus make the first separator sheets 120.

[0243] The cutting members 12 comprise, in the preferred embodiment of the invention, at least a third laser cutting device 17. By way of example, the third laser cutting device 15 may be structurally and functionally similar to the first laser cutting device 13, although physically distinct from the latter.

[0244] The third laser cutting device 15 makes longitudinal and transverse preweakening incisions in the piece of separator strip, defining said first separator sheets 120 arranged according to the matrix pattern with N rows and M columns, as schematically indicated in figure 1 . The first separator sheets 120 thus made remain resting on the separator surface 16 maintaining the arrangement according to the matrix pattern thus made.

[0245] To arrange the second separator sheets 130 coplanar to each other and according to the matrix pattern with N rows and M columns, use is made of the separator plane 16 and the third laser cutting device 16, which provides, in the same manners described above in relation to the arrangement of the first separator sheets 120, to arrange the second separator sheets 130 on the separator plane 16 starting from a piece of separator unwound from the coil 128. As will become clearer hereinafter, the arrangement of the second separator sheets 130 coplanar to each other and according to the matrix pattern with N rows and M columns is carried out after the arrangement of the first separator sheets 120 coplanar to each other and according to the matrix pattern with N rows and M columns, since only first separator sheets 120 or only second separator sheets 130 can be present on the separator plane 16.

[0246] As schematically illustrated in figure 1 , the apparatus 10 comprises a stacking station 18 configured to sequentially receive the first separator sheets 120, the first foils 100, the second separator sheets 110, and the second foils 110. The stacking station 18 is preferably placed in a space obtained between the first plane 11 , the second plane 14 and the separator plane 16, as schematized in figure 1 . The stacking station 18 is equidistant from the first plane 11 , the second plane 14 and the separator plane 16. The stacking station 18 comprises a stacking surface 19 on which the first separator sheets 120, the first foils 100, the second separator sheets 110 and the second foils 110 are positioned one on top of the other. The stacking surface 19 can be the surface of a special pallet (as in the example illustrated in figure 2), or the surface of a conveyor belt (as in the example illustrated in figure 3), or still any surface suitable for the purpose.

[0247] The apparatus 10 further comprises transfer members 20 movable between the first plane 11 and the stacking station 18, between the second plane 14 and the stacking station 18 and between the separator plane 16 and the stacking station 18. The transfer members 20 comprise at least a transfer device 21 comprising a lifting plate 22. The transfer device 21 comprises lifting kinematics 23 connected to the lifting plate 22 for moving the lifting plate 23 to and from the stacking station 18 and for raising and lowering the lifting plate 23, as schematically illustrated in figure 2 and 3. The transfer members 20 may comprise a single transfer device 21 that moves (by moving the lifting plate 23) between the first plane 11 and the stacking station 18, between the second plane 14 and the stacking station 18 and between the separator plane 16 and the stacking station 18, or a plurality of transfer devices 21 . In the latter case, a first transfer device 21 moves between the first plane 11 and the stacking station 18, a second transfer device 21 moves between the second plane 14 and the stacking station 18 and a third transfer device 21 moves between the separator plane 16 and the stacking station 18. This solution is schematically represented in figure 1 .

[0248] In any event, the transfer members 20 comprise a plurality of retaining elements 24 arranged according to a matrix pattern with N rows of retaining elements and M columns of retaining elements. The retaining elements 24 are placed on a lower surface of the lifting plate 23, as schematically illustrated in figure 3. The number N of rows of retaining elements 24 is equal to the number N of rows of the first foils 100 and the number M of columns of retaining elements 24 is equal to the number M of columns of the first foils 100. Each retaining element 24 is configured to withdraw, retain, and release a respective first foil 100, a respective second foil 110, a respective first separator sheet 120, and a respective second separator sheet 130 (in the embodiment having only one transfer device 21 ). Alternatively, each retaining element 24 is configured to withdraw, retain, and release a respective first foil 100, or a respective second foil 110, or a respective first separator sheet 120 and a respective second separator sheet 130 (in the embodiment having a plurality of transfer devices 21 ). In any case, each retaining element 24 comprises a suction device 25 configured to retain by effect of air suction. The suction device comprises N*M aspirators 26 arranged according to a matrix pattern with N rows and M columns. The number of rows of aspirators 26 is equal to the number of rows of the first foils 100 and the number of columns of aspirators 26 is equal to the number of columns of the first foils 100.

[0249] The apparatus 10 further comprises a press 27 configured to exert pressure on the first foils 100, the second foils 110 and the separator sheets 120 when stacked on each other. The press 27 is configured to exert a direct pressing action in a perpendicular direction on the first foils 100, the second foils 110 and the separator sheets 120 when stacked on each other. The press 27 is placed at the stacking station 18. The press 27 may be activated when the transfer members 20 are not placed on the stacking station 18 or are not transferring respective first foils 100, second foils 110 and separator sheets 120 to the stacking station 20.

[0250] The method object of the present invention provides for transferring simultaneously all the first separator sheets 120 from the separator plane 16 to the stacking station 18. This action is carried out by the single transfer device 21 (or by the transfer device 21 dedicated only to the transfer from the separator plane 16 to the stacking station 18) which withdraws simultaneously all the first separator sheets 120 maintaining them arranged exactly according to the matrix pattern with N rows and M columns made on the separator plane 16. In this regard, each aspirator 26 of the suction device 25 withdraws from the separator plane 16, retains and releases in the stacking station 18 a respective first separator sheet 120.

[0251] As soon as the first separator sheets 120 are removed from the separator plane 120, the second separator sheets 130 are arranged on the separator plane 16 coplanar to each other and according to the matrix pattern with N rows and M columns in the same manners as described in relation to the arrangement of the first separator sheets 120.

[0252] While the second separator sheets 130 are arranged on the separator plane 16, and in any case after transferring the first separator sheets 120 to the stacking station 18, it is provided to transfer simultaneously all the first foils 100 from the first plane 11 to the stacking station 18.

[0253] This action is carried out by the single transfer device 21 (or by the transfer device 21 dedicated only to the transfer from the first plane 11 to the stacking station 18) which withdraws simultaneously all the first foils 100 maintaining them arranged exactly according to the matrix pattern with N rows and M columns made on the first plane 11 . In this regard, each aspirator 26 of the suction device 25 withdraws from the first plane 11 , retains and releases in the stacking station 18 a respective first foil 100.

[0254] The first foils 100 are deposited on top of the first separator sheets 120 by completely overlapping the first active portion 104 of each first foil 100 on the respective underlying first separator sheet 120 and by having the first electrical connection portion 106 of each first foil 100 protrude cantilevered from the respective underlying first separator sheet 120, as schematized in figure 8A and 11A. The first foils 100 are further deposited on top of the first separator sheets 120 such that the part of the first electrical connection portion 106 of the first foil 100 which protrudes cantilevered from the underlying first separator sheet 120 overlaps on a first separator sheet 120 adjacent to the underlying first separator sheet 120, as schematically illustrated in figure 8A and 11A.

[0255] In the first embodiment of the first foils 100, the first foils 100 are deposited on top of the first separator sheets 120 such that the first electrical connection portion 106 of the first foil 100 protrudes cantilevered from the second edge 121 b and from the third edge 121 c of the underlying first separator sheet 120, as illustrated in figure 8A. The electrical connection portion 106 of a first foil 100, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered, overlaps on: the first separator sheet 120 placed in the row x-1 when x>1 and placed in the column y; and the first separator sheet 120 placed in the row x and placed in the column y+1 when y<M, where x is comprised between 1 and N and indicates a row number within the matrix pattern with N rows and M columns and where y is comprised between 1 and M and indicates a column number within the matrix pattern with N rows and M columns.

[0256] When x=1 , the electrical connection portion 106 of a first foil 100, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the first separator sheet 120, overlaps only on the first separator sheet 120 placed in the row x and placed in the column y+1 when y<M. When y=M, the electrical connection portion 106 of a first foil 100, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the first separator sheet 120, overlaps only on the first separator sheet 120 placed in the row x-1 when x>1 .

[0257] When x=1 and y=M the electrical connection portion 106 of a first foil 100, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the first separator sheet 120 does not overlap on any other first separator sheet 120.

[0258] In the second embodiment of the first foils 100, the first foils 100 are deposited on top of the first separator sheets 120 such that the first electrical connection portion 106 of the first foil 100 protrudes cantilevered only from the second edge 121 b of the underlying first separator sheet 120, as illustrated in figure 11A.

[0259] The electrical connection portion 106 of a first foil 100, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered, overlaps on: the first separator sheet 120 placed in the row x and placed in the column y+1 when y<M, where x is comprised between 1 and N and indicates a row number within the matrix pattern with N rows and M columns and where y is comprised between 1 and M and indicates a column number within the matrix pattern with N rows and M columns. When y=M the electrical connection portion 106 of a first foil 100, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the first separator sheet 120 does not overlap on any other first separator sheet 120.

[0260] In the second embodiment, during the transfer from the first plane 11 to the stacking station 18, the first foils 100 of a same row are moved away from the first foils of the adjacent row(s). In this regard, the retaining elements 24 of the transfer device 21 are mounted on the lifting plate such that the N rows of retaining elements 24 are movable closer to and away from each other. The N rows of retaining elements 24 are only moved away from each other when the first foils 100 have already been withdrawn and before depositing them on top of the first separator sheets 120. The first foils 100 of a same row are moved away from the first foils of the adjacent row(s) in such a way as to position each first foil 100 in a median position between the third edge 121 c and the fourth edge 121 d of the first separator sheets 120, as illustrated in figure 11A.

[0261] As soon as the second separator sheets 130 have been arranged on the separator plane 16, and in any case after depositing in the stacking station 18 the first foils 100, it is provided to transfer simultaneously all the second separator sheets 130 from the separator plane 16 to the stacking station 18.

[0262] This action is carried out by the single transfer device 21 (or by the transfer device 21 dedicated only to the transfer from the separator plane 16 to the stacking station 18) which withdraws simultaneously all the second separator sheets 130 maintaining them arranged exactly according to the matrix pattern with N rows and M columns made on the separator plane 16. In this regard, each aspirator 26 of the suction device 25 withdraws from the separator plane 16, retains and releases in the stacking station 18 a respective second separator sheet 130.

[0263] The second separator sheets 130 are deposited on top of the first foils 100. The second separator sheets 130 are deposited in the same exact position as the first separator sheets 120. The second separator sheets then completely overlap on the second active portion 105 of each first foil 100. The second electrical connection portions 107 of the first foils 100 protrude cantilevered from the respective second separator sheets 130 exactly in the same manner as described above in relation to the cantilevered protrusion of the first electrical connection portions 106 relative to the first separator sheets 120. As soon as the second separator sheets 130 have been transferred to the stacking station 18, it is provided to transfer simultaneously all the second foils 110 from the second plane 14 to the stacking station 18.

[0264] This action is carried out by the single transfer device 21 (or by the transfer device 21 dedicated only to the transfer from the second plane 14 to the stacking station 18) which withdraws simultaneously all the second foils 110 maintaining them arranged exactly according to the matrix pattern with N rows and M columns made on the second plane 14. In this regard, each aspirator 26 of the suction device 25 withdraws from the second plane 14, retains and releases in the stacking station 18 a respective second foil 110.

[0265] The second foils 110 are deposited on top of the second separator sheets 130 by completely overlapping the first active portion 114 of each second foil 110 on the respective underlying second separator sheet 130 and by having the first electrical connection portion 116 of each second foil 110 protrude cantilevered from the respective underlying second separator sheet 130, as schematized in figure 8B and 11 B. The second foils 110 are further deposited on top of the second separator sheets 130 such that the portion of the first electrical connection portion 116 of the second foil 110 which protrudes cantilevered from the underlying second separator sheet 130 overlaps on a second separator sheet 130 adjacent to the underlying second separator sheet 130, as schematically illustrated in figure 8B and 11 B.

[0266] In the first embodiment of the second foils 110, the second foils 110 are deposited on top of the second separator sheets 130 such that the first electrical connection portion 116 of the second foil 110 protrudes cantilevered from the first edge 131 a and from the fourth edge 131 d of the underlying second separator sheet 130, as illustrated in figure 8B. The electrical connection portion 116 of a second foil 110, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered, overlaps on: the second separator sheet 130 placed in the row x+1 when x<N and placed in the column y; and the second separator sheet 130 placed in the row x and placed in the column y- 1 when y>1 , where x is comprised between 1 and N and indicates a row number within the matrix pattern with N rows and M columns and where y is comprised between 1 and M and indicates a column number within the matrix pattern with N rows and M columns.

[0267] When x=N the electrical connection portion 116 of a second foil 110, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the second separator sheet 130 overlaps only on the second separator sheet 130 placed in the row x and placed in the column y-1 when y>1 . When y=1 the electrical connection portion 116 of a second foil 110, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the second separator sheet 130 overlaps only on the second separator sheet 130 placed in the row x+1 when x<N.

[0268] When x=N and y=1 the electrical connection portion 116 of a second foil 110, placed in the x row of said N rows and in the y column of said M columns, which protrudes cantilevered from the second separator sheet 130 does not overlap on any other second separator sheet 130.

[0269] In the second embodiment of the second foils 110, the second foils 110 are deposited on top of the second separator sheets 130 such that the first electrical connection portion 116 of the second foil 110 protrudes cantilevered only from the first edge 131 a of the underlying second separator sheet 130, as illustrated in figure 11 B.

[0270] The electrical connection portion 116 of a second foil 110, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered, overlaps on: the second separator sheet 130 placed in the row x and placed in the column y- 1 when y>1 , where x is comprised between 1 and N and indicates a row number within the matrix pattern with N rows and M columns and where y is comprised between 1 and M and indicates a column number within the matrix pattern with N rows and M columns.

[0271] When y=1 the electrical connection portion 116 of a second foil 110, placed in the row x of said N rows and in the column y of said M columns, which protrudes cantilevered from the second separator sheet 130 does not overlap on any other second separator sheet 130.

[0272] In the second embodiment, during the transfer from the second plane 14 to the stacking station 18, the second foils 110 of the same row are moved away from the second foils 110 of the adjacent row(s). In this regard, the retaining elements 24 of the transfer device 21 are mounted on the lifting plate such that the N rows of retaining elements 24 are movable closer to and away from each other. The N rows of retaining elements 24 are only moved away from each other when the second foils 110 have already been withdrawn and before depositing them on top of the second separator sheets 130. The second foils 110 of a same row are moved away from the second foils 110 of the adjacent row(s) in such a way as to position each second foil 110 in a median position between the third edge 131 c and the fourth edge 131 d of the second separator sheets 130, as illustrated in figure 11 B.

[0273] Stacking in the stacking station 18 further first separator sheets 120, further first foils 100, further second separator sheets 130 and further second foils 110 may be repeated any number of times, wherein each stacking is implemented as described above and wherein the further first separator sheets 120 are placed in the stacking station 18 exactly in the same position (i.e. in exact overlap) in which the first separator sheets 120 were placed.

[0274] Stacking in the stacking station 18 the first separator sheets 120, the first foils 100, the second separator sheets 130 and the second foils 110 makes an N*M number of stacking groups 140 also arranged according to a matrix pattern with N rows and M columns. When the stacking groups 140 are completed with a predetermined number of first separator sheets 120, of first foils 100, of second separator sheets 130 and of second foils 110, the stacking groups 140 are pressed by the press 27 in a direction perpendicular to the stacking groups 140 in such a way as to compact the same and eliminate any air present between the various foils and separator sheets.

[0275] Each stacking group 140 may be separated from the other stacking groups 140 such that each stacking group 140 defines a respective electrochemical cell. This separation is performed after pressing the stacking groups 140 and possibly after moving the stacking groups from the stacking station 18.

Claims

CLAIMS1 . Method for making electrochemical cells comprising: arranging first foils (100) of a first electrode precursor coplanar to each other and according to a matrix pattern with N rows of first foils (100) and M columns of first foils (100), in which each first foil (100) is physically separated from the other first foils (100); arranging second foils (110) of a second electrode precursor coplanar to each other and according to a matrix pattern with N rows of second foils (110) and M columns of second foils (110), in which each second foil (110) is physically separated from the other second foils (110); arranging, as coplanar to each other, first separator sheets (120) arranged according to a matrix pattern with N rows of first separator sheets (120) and M columns of first separator sheets (120); arranging, as coplanar to each other, second separator sheets (130) arranged according to a matrix pattern with N rows of second separator sheets (130) and M columns of second separator sheets (130); stacking said first separator sheets (120), said first foils (100), said second separator sheets (130) and said second foils (110) with each other to make an N*M number of stacking groups (140) arranged according to a matrix pattern with N rows and M columns wherein each stacking group (140) comprises at least a first separator sheet (120), a first foil (110), a second separator sheet (130) and a second foil (100), at least partially overlapping on each other.

2. Method according to claim 1 , wherein stacking said first separator sheets (120), said first foils (110), said second separator sheets (130) and said second foils (110) with each other comprises: transferring simultaneously all the first separator sheets (120) to a stacking station (18) maintaining said matrix pattern with N rows and M columns; subsequently transferring simultaneously all the first foils (100) to the stacking station (18) maintaining said matrix pattern with N rows and M columns and laying the first foils (100) on top of the first separator sheets (120); subsequently transferring simultaneously all the second separator sheets (130) to the stacking station (18) maintaining said matrix pattern with N rows and M columns and laying the second separator sheets (130) on top of the first foils (100); subsequently transferring simultaneously all the second foils (110) to the stacking station (18) maintaining said matrix pattern with N rows and M columns and layingthe second foils (110) on top of the second separator sheets (130).

3. Method according to claim 1 or 2, wherein transferring simultaneously all the first separator sheets (120) to the stacking station (18) is implemented with said first separator sheets (120) partially physically connected to each other and wherein said first separator sheets (120) are physically separated from each other after stacking said first separator sheets (120), said first foils (100), said second separator sheets (130) and said second foils (110) on each other.

4. Method according to claim 2, wherein arranging first foils (100) of a first electrode precursor comprises arranging each first foil (100) with a first surface (102) and a second surface (103) opposite the first surface (102), wherein the first surface (102) has a first active portion (104) covered with active electrode material and a first electrical connection portion (106) not covered with active electrode material, and wherein the second surface (103) has a second active portion (105) covered with active electrode material and a second electrical connection portion (107) not covered with active electrode material; and wherein arranging second foils (110) of a second electrode precursor comprises making each second foil (110) with a first surface (112) and a second surface (113) opposite the first surface (112), wherein the first surface (112) has a first active portion (114) covered with active electrode material and a first electrical connection portion (116) not covered with active electrode material, and wherein the second surface (113) has a second active portion (115) covered with active electrode material and a second electrical connection portion (117) not covered with active electrode material.

5. Method according to claim 4, wherein laying the first foils (100) on top of the first separator sheets (120) comprises overlapping the first active portion (104) of each first foil (100) on a respective first separator sheet (120), wherein laying the second separator sheets (130) on top of the first foils (100) comprises overlapping each second separator sheet (130) on the second active portion (105) of a respective first foil (100), and wherein laying the second foils (110) on top of the second separator sheets (130) comprises overlapping the first active portion (114) of each second foil (110) on a respective second separator sheet (130).

6. Method according to claim 5, wherein laying the first foils (100) on top of the first separator sheets (120) comprises arranging the first electrical connection portion (106) of a first foil (100) at least partially cantilevered relative to said firstseparator sheet (120) on which the first active portion (104) of the first foil (100) is overlapped, and wherein laying the second foils (110) on top of the second separator sheets (130) comprises arranging the first electrical connection portion (116) of a second foil (110) at least partially cantilevered relative to said second separator sheet (130) on which the first active portion (114) of the second foil (110) is overlapped.

7. Method according to any one of the preceding claims, wherein arranging first foils (100) of a first electrode precursor comprises feeding along a first plane (11 ) a piece of strip of first electrode precursor and making longitudinal notches and transverse notches in said piece of strip of first electrode precursor to define said matrix pattern with N rows of first foils and M columns of first foils (100); wherein arranging second foils (110) of a second electrode precursor comprises feeding along a second plane (14) a piece of strip of second electrode precursor and making longitudinal notches and transverse notches in said piece of second strip of electrode precursor to define said matrix pattern with N rows of second foils and M columns of second foils (110).

8. Method according to any one of the preceding claims, wherein arranging first separator sheets (120) coplanar to each other comprises feeding along a separator plane (16) a first piece of separator strip and making longitudinal incisions and transverse incisions in said first piece of separator strip to define said matrix pattern with N rows of first separator sheets (120) and M columns of first separator sheets; wherein arranging second separator sheets (130) coplanar to each other comprises feeding along said separator plane (16) a second piece of separator strip and making longitudinal incisions and transversal incisions in said second piece of separator strip to define said matrix pattern with N rows of second separator sheets and M columns of second separator sheets (130).

9. Method according to claim 4 and 7, wherein feeding along a first plane (11 ) a piece of strip of first electrode precursor comprises arranging said piece of strip of first electrode precursor with first active portions (104) and with second active portions (105) aligned along N rows and M columns, and wherein feeding along a second plane (14) a piece of strip of second electrode precursor comprises arranging said piece of strip of second electrode precursor with first active portions (114) and with second active portions (115) aligned along N rows and M columns.

10. Method according to claim 9, wherein arranging said piece of strip of first electrode precursor with first active portions (104) and with second active portions (105) aligned along N rows and M columns comprises arranging said piece of strip of first electrode precursor with said first active portions (104) spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows and with said second active portions (105) spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows, and wherein arranging said piece of strip of second electrode precursor with said first active portions (114) and with said second active portions (115) aligned along N rows and M columns comprises arranging said piece of strip of second electrode precursor with said first active portions (114) spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows, and with said second active portions (115) spaced between adjacent columns of said M columns and spaced between adjacent rows of said N rows.11 . Method according to claim 9, wherein arranging said piece of strip of first electrode precursor with first active portions (104) and with second active portions (105) aligned along N rows and M columns comprises arranging said piece of strip of first electrode precursor strip with said first active portions (104) spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows and with said second active portions (105) spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows, and wherein arranging said piece of strip of second electrode precursor with first active portions (114) and with second active portions (115) aligned along N rows and M columns comprises arranging said piece of strip of second electrode precursor strip with said first active portions (114) spaced between adjacent columns of said M columns and adjacent between adjacent rows of said N rows and with said second active portions (115) spaced from each other along said M columns and adjacent to each other along said N rows.

12. Method according to claim 2 and 7, wherein transferring simultaneously all the first foils (100) to the stacking station (18) comprises withdrawing simultaneously all the first foils (100) from the first plane (11 ) and releasing simultaneously all the first foils (100) in the stacking station (18), and wherein transferring simultaneously all the second foils (110) to the stacking station (18) comprises withdrawing simultaneously all the second foils (110) from the second plane (14) and releasing simultaneously all the second foils (110) in the stacking station (18).

13. Method according to claim 12, wherein transferring simultaneously all the first foils (100) to the stacking station (18) further comprises moving the rows of the first foils (100) away from each other after withdrawing simultaneously all the first foils (100) from the first plane (11 ) and before releasing simultaneously all the first foils (100) in the stacking station (18) and wherein transferring simultaneously all the second foils (1 10) to the stacking station (18) further comprises moving the rows of the second foils (110) away from each other after withdrawing simultaneously all the second foils (110) from the second plane (14) and before releasing simultaneously all the second foils (110) in the stacking station (18).

14. Method according to claim 13, wherein moving the rows of first foils (100) away from each other is implemented without releasing the first foils (100) and wherein moving the rows of second foils (110) away from each other is implemented without releasing the second foils (110).

15. Apparatus (10) for making electrochemical cells comprising: a first plane (11 ) configured to receive first foils (100) of a first electrode precursor coplanar to each other and according to a matrix pattern with N rows of first foils (100) and M columns of first foils (100), in which each first foil (100) is physically separated from the other first foils (100); a second plane (14) configured to receive second foils (110) of a second electrode precursor coplanar to each other and according to a matrix pattern with N rows of second foils (110) and M columns of second foils (110), in which each second foil (110) is physically separated from the other second foils (110); a separator plane (16) configured to receive first separator sheets (120) arranged according to a matrix pattern with N rows of first separator sheets (120) and M columns of first separator sheets (120) and to receive second separator sheets (130) arranged according to a matrix pattern with N rows of second separator sheets (130) and M columns of second separator sheets (130); transfer members (20) movable between said first plane (11 ) and a stacking station (18), movable between said second plane (14) and the stacking station (18) and movable between said separator plane (16) and the stacking station (18); wherein said transfer members (20) comprise a plurality of retaining elements (24) arranged according to a matrix pattern with N rows of retaining elements (24) and M columns of retaining elements (24).

16. Apparatus (10) according to claim 15, comprising cutting members (12) placed at the first plane (11 ), the second plane (14) and the separator plane (16) and configured respectively to operate on first pieces of strip of electrode precursor, on second pieces of strip of second electrode precursor, on first pieces of separator strip, and on second pieces of separator strip to make said first foils (100), said second foils (110), said first separator sheets (120) and said second separator sheets (130).

17. Apparatus (10) according to claim 15 or 16, wherein said N rows of retaining elements (24) are movable between a moved-closer condition and a moved-away condition; in said moved-away condition the distance between adjacent rows of retaining elements (24) being greater than the distance between adjacent rows of retaining members (24) in said moved-closer condition.

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