Electrode for cylindrical battery cell

Abstract

The invention relates to an electrode (10, 20) for a cylindrical battery cell (1), comprising a metal support sheet (11, 21) and a layer of active material (13, 23) arranged on the metal support sheet (11, 21) so as to define a second area (Z2) of the metal support sheet (11, 21) which is free of active material (13, 23); said second area (Z2) having current collecting tabs (50) extending projecting from the metal support sheet (11, 21) between a proximal portion (51) and a distal edge (53); said second area (Z2) comprising at least one folding notch (60) provided at the proximal portion (51) of one of the current collecting tabs (50). The invention also relates to an electric battery cell (1) comprising two electrodes (10,20) of such a type, and a method of manufacturing such an electrode (10,20). Figure 2

Description

Title of the invention: Electrode for cylindrical battery cell Technical field of the invention

[0001] The present invention relates to an electrode for a cylindrical battery cell, as well as to a cylindrical battery cell comprising at least two electrodes. State of the art

[0002] In the field of secondary batteries, and in particular batteries for electric vehicles, it is known to manufacture so-called cylindrical battery cells. Generally, such battery cells comprise two electrodes: an anode and a cathode in the form of sheets. These electrodes are then wound around a winding mandrel to form a main winding forming the cylindrical battery cell. Between the anode and the cathode, a separator is arranged configured to prevent the formation of a short circuit between the two electrodes. The main winding is then inserted into a housing serving in particular to protect the main winding, and / or to allow the insertion of an electrolyte used to transport ions between the two electrodes.

[0003] These battery cells have the advantage of being able to be easily manufactured by simply winding the electrode and separator strips, which makes it possible to increase production rates and thus reduce costs.

[0004] In order to collect the current generated by the battery cell in operation, it is known from the state of the art to provide that the electrode strips are formed by the deposition of an active material on an electrically conductive strip. A portion of this electrically conductive strip is devoid of active material, and can be cut on one of the edges to form current collection tabs. Thus, once wound, the main winding comprises on one side tabs electrically connected to the anode, and on the other side, tabs electrically connected to the cathode.

[0005] The tabs allow an electrical connection to be made between different areas of the same electrode, so that the polarity of an entire electrode strip can be sensed from outside the battery cell.

[0006] To collect all of the current from each of the tabs, it is known to deposit a current collector on said tabs, and to weld the current collector with the tabs. Thus, there is for each of the electrodes, a current collector. The first current collector can be electrically connected to the cover of the housing, and the second current collector can be electrically connected to the housing, the cover of the housing and the housing being electrically isolated from each other. As a result, a current can flow through the housing, for example via its cylindrical wall, to provide electrical energy to the vehicle.

[0007] The electrical connection of a current collector is generally made by affixing said current collector to the tabs. Under the effect of the pressure exerted by the current collector, the tabs bend. The current collector is then secured to the tabs, by welding on a face opposite to that which is in contact with the tabs.

[0008] Indeed, when applying the current collector to the tabs, it is not possible to know precisely the orientation and arrangement of the tabs between the current collector and the main winding.

[0009] In particular due to the small thickness of the electrode sheets and therefore of the tabs, it is difficult to properly control the folding of the tabs on each side of the main winding. Furthermore, the fact that the electrodes are wound around the winding mandrel induces a curvature at the level of the tabs. These two effects have direct consequences on the efficiency of the folding of the tabs. Indeed, the folding induces mechanical stresses such that the electrode sheet can tear, thus damaging the main winding. The performance of the cell can then be impacted. In addition, accidents such as short circuits can occur during use.

[0010] There is therefore a need to better control the folding of current collection tabs. In particular, manufacturers wish to maintain the integrity of the tabs and electrode sheets during folding.

[0011] Object of the invention

[0012] The present invention aims to propose a solution which responds to all or part of the aforementioned problems.

[0013] This object can be achieved by implementing an electrode for a cylindrical battery cell, said electrode comprising a metal support sheet and a layer of active electrode material, the layer of active material being arranged on the metal support sheet so as to define a first area of ​​the metal support sheet which is in contact with the layer of active material and a second area of ​​the metal support sheet which is devoid of active material; said second area being arranged on a peripheral edge of the metal support sheet and having current collection tabs configured to collect an electric current, said current collection tabs extending projecting from the metal support sheet between a proximal portion directed towards the layer of active material and a free distal edge opposite said proximal portion;said second zone comprising at least one folding notch provided on the peripheral edge of the metal support sheet at the proximal part of one of the; current collection tabs.

[0014] The previously described arrangements make it possible to provide an electrode for a cylindrical battery cell in which the folding of the current collection tabs is facilitated. In addition, this makes it possible to avoid tearing of the electrode sheet when folding the current collection tabs.

[0015] The electrode may further have one or more of the following characteristics, taken alone or in combination.

[0016] According to one embodiment, each current collection tab comprises at least one folding notch.

[0017] In this way, it is possible to improve the folding of all the current collecting tabs.

[0018] According to one embodiment, at least one of the current collection tabs comprises two folding notches opposite each other with respect to said at least one current collection tab.

[0019] Thus, the folding of this current collection tab is made easier. This arrangement makes it possible to avoid tearing of the electrode sheet, said notches being deliberately arranged at the location where the mechanical stresses are the highest.

[0020] According to one embodiment, at least one folding notch is provided in the metal support sheet at the proximal portion, and outside the current collection tab.

[0021] Thus, it is possible to improve the folding of the current tab, without compromising the robustness of the current collection tab during folding.

[0022] According to one embodiment, the folding notch has a notch width measured along the peripheral edge, and in which the current collection tab at which said folding notch is provided has a tab width measured along the peripheral edge, a ratio of said tab width and said notch width being between 1 / 1000 and 1 / 10.

[0023] Thus, it is possible to cut the second zone to facilitate the folding of the current collection tabs by limiting the quantity of material removed. The electrode is thus more robust. Furthermore, the arrangements previously described make it possible not to slow down the cutting speed of the folding notches too much, which makes it possible to maintain a good production rate of the electrode.

[0024] According to one embodiment, the second zone comprises junction portions, where each junction portion is arranged between two successive current collection tabs, and adjacent to at least one folding notch, electrode in which: - at least one of the junction portions has a junction height measured perpendicularly along the peripheral edge, and in which - said at least one folding notch adjacent to this joining portion has a notch depth measured perpendicularly along the peripheral edge;

[0025] a ratio of said notch depth and said junction height being between 1 / 10 and 3 / 5.

[0026] In this way, it is possible to provide sufficient margin when the cuts are made, to ensure that the layer of active material is not damaged or compromised.

[0027] The aim of the invention can also be achieved by implementing an electric battery cell for an electric vehicle, said cell comprising at least one successive stack of a sheet: - a first electrode as described previously; - a first insulating separator; - a second electrode as described previously, of polarity opposite to the first electrode; - a second insulating separator;

[0028] said at least one stack being wound on itself around a winding axis so as to form a substantially cylindrical winding.

[0029] Thus, it is possible to form a cylindrical battery cell in which the folding of the current collection tabs is controlled.

[0030] The cell may further exhibit one or more of the following characteristics, taken alone or in combination.

[0031] According to one embodiment, for at least one electrode chosen from the first electrode and the second electrode, each current collection tab is spaced from the current collection tab which precedes it along the peripheral edge by a variable interval which increases between an inner end of the sheet arranged radially closest to the winding axis, and an outer end of the sheet arranged radially furthest from the winding axis.

[0032] The previously described arrangements allow the current collecting tabs to be aligned along a radial direction, when the electrodes are wound to form the winding. It is then possible to distribute series of current collecting tabs in a determined arrangement, which is considered more efficient for current collection.

[0033] According to one embodiment, in the winding, the first electrode and / or the second electrode comprises several series each comprising a plurality of current collection tabs of the first electrode and / or the second electrode, the current collection tabs of a given series being aligned in a radial direction substantially perpendicular to the winding axis from sen possibly the winding axis towards a periphery of the winding.

[0034] The arrangements described above make it possible to provide a cylindrical battery cell in which the current collection tabs are grouped together before the welding operation with the current collector, which facilitates the welding operation, and limits the risk of bending in unwanted directions of the current collection tabs.

[0035] According to one embodiment, the current collection tabs of the same series have a substantially constant tab width, said tab width being measured perpendicular to the radial direction.

[0036] Thus, the exchange surface between the different current collection tabs folded together is maximized, which improves current extraction.

[0037] The object of the invention can also be achieved by implementing a method for manufacturing an electrode for a cylindrical battery cell, the manufacturing method comprising the following steps: - a step of providing a metal support sheet; - a coating step in which a layer of active electrode material is coated on the metal carrier sheet so as to define a first area of ​​the metal carrier sheet which is in contact with the layer of active material and a second area of ​​the metal carrier sheet which is devoid of active material, said second area being disposed on a peripheral edge of the metal carrier sheet; - a tab cutting step in which the second area is cut to form current collecting tabs extending protruding from the metal support sheet between a proximal portion directed towards the layer of active material and a free distal edge opposite said proximal portion; - a notch forming step, in which at least one folding notch is formed on the peripheral edge of the metal support sheet at the proximal portion of one of the current collecting tabs.

[0038] The arrangements described above make it possible to manufacture an electrode for an electric battery cell having current collecting tabs that are simple to fold.

[0039] According to one embodiment, the step of cutting tabs and the step of forming notches are implemented simultaneously.

[0040] In this way, the manufacturing process includes fewer manufacturing steps, so it is faster to implement and less expensive. This is particularly suitable for large-scale industrial applications.

[0041] Brief description of the drawings

[0042] Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings in which:

[0043] [Fig-1] [Fig.l] is a schematic view of an electrode according to a method of rea particular use of the invention.

[0044] [Fig.2] [Fig.2] is a schematic view of the dimensions of two electrodes according to a particular embodiment of the invention.

[0045] [Fig.3] [Fig.3] is a schematic view of a battery cell according to a method of particular embodiment of the invention.

[0046] [Fig.4] [Fig.4] is a schematic view of a manufacturing process according to a particular embodiment of the invention. Detailed description

[0047] In the figures and in the remainder of the description, the same references represent identical or similar elements. In addition, the different elements are not shown to scale so as to enhance the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with each other.

[0048] As illustrated in Figures 1 to 3, the invention relates to an electrode 10, 20 for a cylindrical battery cell 1, as well as such an electric battery cell 1 for an electric vehicle, for example an electrically powered vehicle.

[0049] As can be seen in [Fig.l], cell 1 comprises at least one successive stack of a sheet: - a first electrode 10; - a first insulating separator 15; - a second electrode 20, of opposite polarity to the first electrode 10; and - a second insulating separator 25.

[0050] The first electrode 10 and the second electrode 20 may each comprise a metal support sheet 11, 21 and a layer of active electrode material 13, 23 disposed on said metal support sheet 11, 21.

[0051] The first electrode 10 may in particular comprise a first metal sheet 11 in the form of a thin strip, on which a layer of a first active material 13 is deposited. In the case where the first electrode is an anode, the first metal sheet 11 may comprise copper. In the same way, the second electrode 20 may comprise a second metal sheet 21 in the form of a thin strip, on which a layer of a first active material 13 is deposited. of a second active material 23. In the case where the second electrode is a cathode, the second metal sheet 21 may comprise aluminum.

[0052] Whatever the electrode 10, 20 considered, the layer of active material 13, 23 is arranged on the metal support sheet 11, 21 so as to define a first zone Z1 of the metal support sheet 11, 21 which is in contact with the layer of active material 13, 23 and a second zone Z2 of the metal support sheet 11, 21 which is devoid of active material 13, 23. This second zone Z2 is arranged on a peripheral edge 12, 22 of the metal support sheet 11, 21.

[0053] Generally, the layer of first active material 13 and the layer of second active material 23 are each coated over the entire length of the metal support sheet 11, 21, with the exception of the second zone Z2 forming a peripheral strip, arranged on the peripheral edge 12, 22 of the metal support sheet 11, 21.

[0054] The second zone Z2 has current collection tabs 50 configured to collect an electric current, which extend projecting from the metal support sheet 11, 21 between a proximal portion 51 directed towards the layer of active material 13, 23 and a free distal edge 53 opposite said proximal portion 51. The current collection tabs 50 are therefore arranged on the peripheral edge 12, 22 of the metal support sheet 11, 21 devoid of active material.

[0055] Between each of the electrodes 10, 20, a separator strip 15, 25 is arranged so that no electrical contact is possible between the first electrode 10 and the second electrode 20. Furthermore, it is generally provided that the first electrode 10 and the second electrode 20 are offset along a winding axis denoted "X" so that the second zones Z2 without active material coating are offset on either side of the separator strips 15, 25. The at least one stack is wound on itself around the winding axis X so as to form a substantially cylindrical winding 30.

[0056] In the winding 30, the first electrode 10 and / or the second electrode 20 may comprise several series 52 each comprising a plurality of the current collection tabs 50 of the first electrode 10 and / or the second electrode 20. The current collection tabs 50 of a given series 52 may then be aligned in a radial direction R substantially perpendicular to the winding axis X from substantially the winding axis X towards a periphery of the winding 30. By “aligned” is meant that the current collection tabs 50 overlap angularly. The arrangements previously described make it possible to propose a cylindrical battery cell 1 in which the current collection tabs 50 are grouped together before the welding operation with the current collector, which facilitates the welding operation, and limits the risk of bending the current collecting tabs 50 in unwanted directions.

[0057] According to the variant illustrated in Figures 1 and 2, each current collection tab 50 may be spaced from the current collection tab 50 which precedes it along the peripheral edge 12, 22 by a variable interval denoted “NG” which increases between an inner end of the sheet arranged radially closest to the winding axis X, and an outer end of the sheet arranged radially furthest from the winding axis X.Such a variable interval NG can be defined by the following formula: NG = g + n*l, where g corresponds to the interval separating the current collection tab 50 closest to a winding mandrel used to wind the winding 30 and the current collection tab 50 which directly follows it, where n corresponds to the current collection tab 50 arranged in the nth place relative to the current collection tab 50 closest to a winding mandrel, and where 1 corresponds to the length by which the winding spiral increases as a function of the thickness of the stack of electrodes 10, 20, and of the separator strips 15, 25. The arrangements previously described make it possible to align the current collection tabs 50 of the same series 52 along the radial direction R, when the electrodes 10, 20 are wound to form the winding 30.It is then possible to distribute series 52 of current collection tabs 50 according to a determined arrangement, which is more efficient for carrying out current collection.

[0058] Although this is not limiting, it may be advantageous to provide that the series 52 are angularly distributed around the winding axis X in a constant manner. In this way, it is possible to achieve a current collection uniformly distributed around the winding axis X. Furthermore, the current collection tabs 50 of the same series 52 may have a substantially constant tab width w50, said tab width w50 being measured perpendicular to the radial direction R. Thus, the exchange surface between the different current collection tabs 50 folded together is maximized, which improves current extraction.

[0059] As can be seen in Figures 1 to 3, said second zone Z2 further comprises at least one folding notch 60 provided on the peripheral edge 12, 22 of the metal support sheet 11, 21 at the proximal portion 51 of one of the current collection tabs 50. The presence of a folding notch 60 makes it easier to fold the corresponding current collection tab 50 while avoiding tearing of the electrode sheet 10, 20 when folding the current collection tabs 50.

[0060] Advantageously, each current collection tab 50 may comprise at least one folding notch 60. In this way, it is possible to improve the folding of all the current collection tabs 50. More specifically, the current collection tabs 50 may comprise two folding notches 60 opposite each other with respect to said at least one current collection tab 50. In other words, the folding notches 60 are provided in the metal support sheet 11, 21 at the proximal portion 51, on either side of the current collection tab 50. Thus, the folding of this current collection tab 50 is made easier. This arrangement makes it possible to avoid tearing of the electrode sheet, said notches being deliberately arranged at the location where the mechanical stresses are highest.

[0061] As can be seen in the figures, the folding notches 60 can be provided in the metal support sheet 11, 21 at the proximal portion 51, and outside the current collection tab 50. Thus, it is possible to improve the folding of the current tab, without compromising the robustness of the current collection tab 50 during folding.

[0062] [Fig. 2] shows an embodiment of the first electrode 10 and the second electrode 20, and specifies advantageous dimension ratios. As indicated above, the electrode 10, 20 is generally in the form of a sheet extending in an extension direction denoted “Y”, which corresponds to the greatest length of the electrode sheet 10, 20, i.e. the direction along which the electrode sheet extends. The winding axis X is then generally perpendicular to the extension direction.

[0063] Each folding notch 60 may then have a notch width w60 measured along the peripheral edge 12, 22, i.e. along the direction of extension Y. The current collection tab 50 at which said folding notch 60 is provided may have a tab width w50 measured along the peripheral edge 12, 22, i.e. along the direction of extension Y. In this case, it may be advantageous for a ratio of said tab width w50 and said notch width w60 to be between 1 / 1000 and 1 / 10. Thus, it is possible to cut out the second zone Z2 to facilitate the folding of the current collection tabs 50 by limiting the quantity of material removed. The electrode 10, 20 is thus more robust. Furthermore, the arrangements described above make it possible not to slow down the cutting speed of the folding notches 60 too much, which makes it possible to maintain a good production rate of the electrode 10, 20..

[0064] Furthermore, the folding notch 60 may have a notch depth h60 measured perpendicularly along the peripheral edge 12, 22. When the electrodes 10, 20 are wound to form the winding 30, then the notch depth h60 is measured along an axis parallel to or coincident with the winding axis X. Generally, said notch depth h60 is strictly less than a tab height h50 of the current collection tab 50, so as not to weaken the base of the current tab 50.

[0065] The second zone Z2 may also comprise junction portions 61, where each junction portion 61 is arranged between two successive current collection tabs 50. Each junction portion 61 is adjacent to at least one folding notch 60. The junction portions 61 may have a junction height h61 measured perpendicularly along the peripheral edge 12, 22. It may then be advantageous to provide that a ratio of the notch depth h60 and the junction height h61 is between 1 / 10 and 3 / 5. In this way, it is possible to provide sufficient margin when the cuts are made, to ensure that the active material layer 13, 23 is not damaged or compromised.

[0066] All of the arrangements previously described make it possible to propose an electrode 10, 20 for a cylindrical battery cell 1 in which the folding of the current collection tabs 50 is facilitated. Indeed, when folding the current collection tabs 50, an angular degree of freedom a50 is permitted, which makes it possible to avoid tearing of the electrode sheet 10, 20. This also makes it possible to form a cylindrical battery cell 1 in which the folding of the current collection tabs 50 is controlled.

[0067] The invention also relates to a method of manufacturing such an electrode 10, 20 for a cylindrical battery cell 1. An embodiment of the manufacturing method is illustrated in [Fig.4].

[0068] This manufacturing method firstly comprises a step E1 of providing a metal support sheet 11, 21. Then, a coating step E2 is implemented in which a layer of active material 13, 23 of electrode is coated on the metal support sheet 11, 21 so as to define the first zone Z1 of the metal support sheet 11, 21 which is in contact with the layer of active material 13, 23 and the second zone Z2 of the metal support sheet 11, 21 which is devoid of active material 13, 23. The second zone Z2 is then arranged on the peripheral edge 12, 22 of the metal support sheet 11, 21.

[0069] Next, a step E3 of cutting tabs is implemented, in which the second zone Z2 is cut to form current collection tabs 50 extending in projection from the metal support sheet 11, 21 between a proximal part 51 directed towards the layer of active material 13, 23 and a free distal edge 53 opposite said proximal part 51.

[0070] The manufacturing method also comprises a notch forming step E4, in which at least one folding notch 60 is formed on the peripheral edge 12, 22 of the metal support sheet 11, 21 at the proximal portion 51 of one of the current collecting tabs 50.

[0071] As illustrated in [Fig.4], it is advantageous to implement the tab cutting step E3 and the notch forming step E4 simultaneously. In this way, the manufacturing method comprises fewer manufacturing steps, it is therefore faster to implement and less expensive. This is particularly suitable for large-scale industrial applications.

[0072] The arrangements described above make it possible to manufacture an electrode 10, 20 for an electric battery cell 1 having current collection tabs 50 that are simple to bend.

Claims

Claims

1. An electrode (10, 20) for a cylindrical battery cell (1), said electrode (10, 20) comprising a metal support sheet (11, 21) and an electrode active material layer (13, 23), the active material layer (13, 23) being arranged on the metal support sheet (11, 21) so as to define a first area (Z1) of the metal support sheet (11, 21) which is in contact with the active material layer (13, 23) and a second area (Z2) of the metal support sheet (11, 21) which is devoid of active material (13, 23);said second zone (Z2) being arranged on a peripheral edge (12, 22) of the metal support sheet (11, 21) and having current collection tabs (50) configured to collect an electric current, said current collection tabs (50) extending projecting from the metal support sheet (11, 21) between a proximal portion (51) directed towards the layer of active material (13, 23) and a free distal edge (53) opposite said proximal portion (51); said second zone (Z2) comprising at least one folding notch (60) provided on the peripheral edge (12, 22) of the metal support sheet (11, 21) at the proximal portion (51) of one of the current collection tabs (50).;

2. The electrode (10, 20) of claim 1, wherein each current collecting tab (50) comprises at least one folding notch (60).

3. Electrode (10, 20) according to any one of claims 1 or 2, wherein at least one of the current collecting tabs (50) comprises two folding notches (60) opposite each other with respect to said at least one current collecting tab (50).

4. An electrode (10, 20) according to any one of claims 1 to 3, wherein said at least one folding notch (60) is provided in the metal support sheet (11, 21) at the proximal portion (51), and outside the current collecting tab (50).

5. An electrode (10, 20) according to any one of claims 1 to 4, wherein the folding notch (60) has a notch width (w60) measured along the peripheral edge (12, 22), and wherein the current collecting tab (50) at which said folding notch (60) is provided has a tab width (w50) measured along the peripheral edge (12, 22), a ratio of said width of tongue (w50) and of said notch width (w60) being between 1 / 1000 and 1 / 10.

6. Electrode (10, 20) according to any one of claims 1 to 5, wherein the second zone (Z2) comprises junction portions (61), where each junction portion (61) is arranged between two successive current collection tabs (50), and adjacent to at least one folding notch (60), electrode (10, 20) in which: • at least one of the junction portions (61) has a junction height (h61) measured perpendicularly along the peripheral edge (12, 22), and in which • said at least one folding notch (60) adjacent to this junction portion (61) has a notch depth (h60) measured perpendicularly along the peripheral edge (12, 22); a ratio of said notch depth (h60) and said junction height (h61) being between 1 / 10 and 3 / 5.

7. Electric battery cell (1) for an electric vehicle, said cell (1) comprising at least one successive stack of a sheet: • of a first electrode (10) according to any one of claims 1 to 6; • of a first insulating separator (15); • of a second electrode (20) according to any one of claims 1 to 6, of polarity opposite to the first electrode (10); • of a second insulating separator (25); said at least one stack being wound on itself around a winding axis (X) so as to form a substantially cylindrical winding (30).

8. Cell (1) according to claim 7, wherein for at least one electrode (10, 20) selected from the first electrode (10) and the second electrode (20), each current collection tab (50) is spaced from the current collection tab (50) which precedes it along the peripheral edge (12, 22) by a variable interval (NG) which increases between a radially disposed inner sheet end the closer to the winding axis (X), and an outer sheet end arranged radially furthest from the winding axis (X).

9. Cell (1) according to any one of claims 7 or 8, wherein in the winding (30), the first electrode (10) and / or the second electrode (20) comprises several series (52) each comprising a plurality of current collection tabs (50) of the first electrode (10) and / or the second electrode (20), the current collection tabs (50) of a given series (52) being aligned in a radial direction (R) substantially perpendicular to the winding axis (X) from substantially the winding axis (X) towards a periphery of the winding (30).

10. Cell (1) according to claim 9, in which the current collection tabs (50) of the same series (52) have a substantially constant tab width (w50), said tab width (w50) being measured perpendicular to the radial direction (R).

11. A method of manufacturing an electrode (10, 20) for a cylindrical battery cell (1), the manufacturing method comprising the following steps: • a step of providing (El) a metal support sheet (11, 21); • a coating step (E2) in which a layer of active material (13, 23) of electrode is coated on the metal support sheet (11, 21) so as to define a first area (Zl) of the metal support sheet (11, 21) which is in contact with the layer of active material (13, 23) and a second area (Z2) of the metal support sheet (11, 21) which is devoid of active material (13, 23), said second area (Z2) being arranged on a peripheral edge (12, 22) of the metal support sheet (11, 21);• a step (E3) of cutting tabs in which the second zone (Z2) is cut to form current collection tabs (50) extending projecting from the metal support sheet (11, 21) between a proximal part (51) directed towards the layer of active material (13, 23) and a free distal edge (53) opposite said proximal part (51); • a step of forming notches (E4), in which at least one folding notch (60) is formed on the peri- edge; spherical (12, 22) of the metal support sheet (11, 21) at the proximal portion (51) of one of the current collecting tabs (50).

12. A manufacturing method according to claim 11, wherein the step of cutting (E3) tabs and the step of forming notches (E4) are carried out simultaneously.

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