Electrochemical cells, battery modules and batteries incorporating such cells

Abstract

The invention relates to a battery module comprising: - an electrochemical cell, - an electrical connection bar; the electrochemical cell incorporating - a first edge having a first edge part facing a lateral edge of the electrical connection bar; - an electrical connection tab protruding from the first edge and intended to be connected to a main face of the electrical connection bar, this tab having a variable length along the first edge part, this length being measured perpendicularly in relation to the first edge part; when connected to the main face, the tab extends beyond the halfway point of the width of this electrical connection bar along at least a portion of the first edge part, the halfway point of the width of the electrical connection bar being measured in a direction perpendicular to the lateral edge.

Description

Electrochemical cells and battery modules and batteries incorporating such cells

[0001] The present invention relates to electrochemical cells, and more particularly to the electrical connection of such cells in a battery module or in an electric battery intended to equip a motor vehicle at least partially powered by electric battery propulsion energy. The invention also relates to battery modules, battery packs, and electric batteries comprising such cells.

[0002] An electric battery intended for use in a hybrid or electric vehicle comprises a battery pack with multiple modules or battery blocks, each containing a plurality of electrochemical cells mechanically assembled in one or more rows and electrically connected in series or parallel. An electric battery is defined as a set of electrochemical cells assembled within a support structure, either through intermediate grouping into modules or according to an architecture known as "Cell-To-Pack" (CTP) or "Cell-To-Chassis" (CTC), in which the cells are arranged adjacently without intermediate grouping into modules. This method of direct cell integration results in a battery with increased compactness, reduced mass, and improved energy density compared to traditional architectures using intermediate modules.Thus, unless otherwise specified, the term "electric battery" (whether a CTP battery, a CTC battery, or a modular battery, depending on the cell integration method) refers to a plurality of electrochemical cells arranged, with or without intermediate modules, within a single structure. A battery module, or a battery pack incorporating a plurality of battery modules, generally provides additional functions such as encapsulation, mechanical protection, and thermal or electrical monitoring, functions that are absent or distributed differently in CTP or CTC architectures.

[0003] The electrical connection between two adjacent electrochemical cells in the same row, whether within a battery module or, more generally, an electric battery, is ensured by a busbar, commonly called a "busbar" in English. This busbar, made of a conductive material, connects the terminals (or poles) of two adjacent electrochemical cells. The busbar has two main flat faces, opposite each other, connected by at least two opposing lateral edges.

[0004] Each electrical connection terminal is in the form of a flexible metal strip or, more generally, a tab, designed to be bent against a main face of the electrical connecting bar and welded there. Indeed, a common method for electrically connecting two adjacent electrochemical cells in a battery module or battery pack involves positioning an electrical connecting bar so that it extends between the two electrical connecting tabs opposite two adjacent electrochemical cells, bending these electrical connecting tabs onto the same flat main face of the electrical connecting bar, and laser-welding each electrical connecting tab to the electrical connecting bar.

[0005] The electrical connecting bar is designed to be sufficiently wide (with the connection direction between the two electrochemical cells perpendicular to the planes or stacks of the two adjacent cells) to accommodate the two electrical connection terminals separately and without any overlap. Most often, the main flat face of the electrical connecting bar, intended to receive the two tabs, is divided into two rectangular areas, each located on the side of a cell. Each of these areas is soldered to the corresponding electrical connection tab—that is, the one on the same side—so as to electrically connect the two adjacent electrochemical cells without any overlap of the two tabs on the electrical connecting bar.

[0006] However, such an electrical connecting bar is not entirely satisfactory, particularly due to its size. An inherent drawback of the electrical connecting bar is that it increases the overall size and weight of the battery modules, in addition to its manufacturing cost due to the amount of material used. It has also been observed that the weld between the electrical connecting bar and the electrical connection tabs is frequently fragile, making it prone to cracking.

[0007] An object of the present invention is to ensure reliable electrical connections between the connection terminals of the electrochemical cells of a battery module or an electric battery, while reducing the size of the battery modules or electric batteries.

[0008] Another object of the present invention is to propose an electrochemical cell allowing the use of a narrow electrical connecting bar for a simple and compact series or parallel arrangement of electrochemical cells.

[0009] Another object of the present invention is to improve the energy density of electric batteries or battery packs.

[0010] Another object of the present invention is to improve the overall performance of hybrid or electric vehicles.

[0011] To this end, it is proposed, firstly, a battery module comprising: - a first electrochemical cell integrating a stack of electrodes separated from each other by a porous separating film, - an electrical connecting bar for electrically connecting the first electrochemical cell to a second electrochemical cell, adjacent to the first electrochemical cell, in said battery module, the electrical connecting bar having a first main flat face, a second main flat face opposite the first face, connected by at least a first lateral edge and a second lateral edge opposite the first lateral edge; the first electrochemical cell further integrating a first edge comprising a first part of the edge opposite the first lateral edge of the electrical connecting bar;a first electrical connection tab extending beyond said first edge intended to be connected to the first main face of the electrical connecting bar, this first electrical connection tab having a variable length along the first part of the edge, this length being measured perpendicular to the first part of the edge; the first tab extending, when connected to the first main face of the electrical connecting bar, beyond the mid-width of this electrical connecting bar along at least a portion of the first part of the edge, the mid-width of the electrical connecting bar being measured in a direction perpendicular to said first lateral edge and second lateral edge.;

[0012] Various additional features may be provided, alone or in combination: - the first tab of the first electrochemical cell is made of a first material comprising a first metal, the electrical connecting bar being made of a second material comprising the first metal; - the first metal is predominant in the first material and in the second material; - the first electrical connecting tab comprises a section of substantially rectangular or triangular shape; - the electrode stack is arranged in a flexible bag, the first electrochemical cell further comprising an electrolyte in the bag; - the first electrochemical cell comprises a second edge opposite the first edge;a second electrical connection tab extending from said second edge, this second tab being substantially symmetrical to the first tab with respect to a median plane of the first electrochemical cell substantially perpendicular to the electrode stack or with respect to a central axis of the first electrochemical cell substantially perpendicular to the electrode stack; - the battery module further comprises a second electrochemical cell adjacent to the first electrochemical cell in said battery module, this second electrochemical cell incorporating a stack of electrodes separated from each other by a porous separator film, a third edge comprising a third edge portion opposite the second lateral edge of the electrical connecting bar; a third electrical connection tab extending from said third edge intended to be connected to the first main face of the electrical connecting bar;the third tab extending, when connected to the first main face of the electrical connecting bar, beyond the mid-width of this electrical connecting bar along at least a portion of the third edge part; - a first laser weld bead in a non-overlapping area of ​​the first tab and the third tab so as to weld the tab corresponding to this area to the electrical connecting bar; - the battery module further includes a second laser weld bead in an overlapping area between the first tab and the third tab, so as to weld the first tab to the third tab; - the electrical connecting bar is substantially flat in shape.

[0013] Secondly, a battery pack incorporating a plurality of the battery modules presented above is proposed.

[0014] Thirdly, an electric battery is proposed comprising: - a first electrochemical cell integrating a stack of electrodes separated from each other by a porous separating film, - an electrical connecting bar for electrically connecting the first electrochemical cell to a second electrochemical cell, adjacent to the first electrochemical cell, in said electric battery, the electrical connecting bar having a first main flat face, a second main flat face opposite the first face, connected by at least a first lateral edge and a second lateral edge opposite the first lateral edge; the first electrochemical cell further integrating a first edge comprising a first part of an edge opposite the first lateral edge of the electrical connecting bar;a first electrical connection tab extending beyond said first edge intended to be connected to the first main face of the electrical connecting bar, this first electrical connection tab having a variable length along the first part of the edge, this length being measured perpendicular to the first part of the edge; the first tab extending, when connected to the first main face of the electrical connecting bar, beyond the mid-width of this electrical connecting bar along at least a portion of the first part of the edge, the mid-width of the electrical connecting bar being measured in a direction perpendicular to said first lateral edge and second lateral edge.;

[0015] Various additional features may be provided, alone or in combination: - the first tab of the first electrochemical cell is made of a first material comprising a first metal, the electrical connecting bar being made of a second material comprising the first metal; - the first metal is predominant in the first material and in the second material; - the first electrical connecting tab comprises a section of substantially rectangular or triangular shape; - the electrode stack is arranged in a flexible bag, the first electrochemical cell further comprising an electrolyte in the bag; - the first electrochemical cell comprises a second edge opposite the first edge;a second electrical connection tab extending from said second edge, this second tab being substantially symmetrical to the first tab with respect to a median plane of the first electrochemical cell substantially perpendicular to the stack of electrodes or with respect to a central axis of the first electrochemical cell substantially perpendicular to the stack of electrodes; - the electric battery further comprises a second electrochemical cell adjacent to the first electrochemical cell in said electric battery, this second electrochemical cell incorporating a stack of electrodes separated from each other by a porous separating film, a third edge comprising a third edge part opposite the second lateral edge of the electrical connection bar;a third electrical connection tab extending beyond said third edge intended to be connected to the first main face of the electrical connecting bar; the third tab extending, when connected to the first main face of the electrical connecting bar, beyond the mid-width of this electrical connecting bar along at least a portion of the third edge part; - a first laser weld bead in a non-overlapping zone of the first tab and the third tab so as to weld the tab corresponding to this zone to the electrical connecting bar; - the electrical battery further comprises a second laser weld bead in an overlapping zone between the first tab and the third tab, so as to weld the first tab to the third tab; - the electrical connecting bar is substantially flat in shape.

[0016] Other features and advantages of the invention will become clearer and more concrete upon reading the following description of embodiments, which is made with reference to the accompanying drawings in which:

[0017] The figure schematically illustrates an electrochemical cell incorporating electrical connection tabs according to various embodiments;

[0018] The figure schematically illustrates an electrochemical cell incorporating electrical connection tabs according to a first embodiment;

[0019] The figure schematically illustrates an electrochemical cell incorporating electrical connection tabs according to a second embodiment;

[0020] The figure schematically illustrates part of a battery module, battery pack or electric battery according to various embodiments;

[0021] The figure schematically illustrates an electrical connecting bar electrically connecting two adjacent electrochemical cells in a battery module, battery pack or electric battery according to a first embodiment;

[0022] The figure schematically illustrates an electrical connecting bar electrically linking two adjacent electrochemical cells in a battery module, battery pack or electric battery according to a second embodiment.

[0023] Referring to Figures 1-3, an electrochemical cell 10 is shown, intended for integration into a device 20, such as a battery module 20, a battery pack 20, or an electric battery 20. This electrochemical cell 10 incorporates a stack of electrodes separated from each other by a porous separator film. The electrode stack is arranged (or wrapped) in a flexible pouch containing an electrolyte. The electrochemical cell 10 can, in fact, be a pouch cell or a flexible-packaged cell, commonly called a "pouch cell."

[0024] The electrochemical cell 10 comprises a first edge 1. This first edge 1 refers to an outer area or peripheral region that at least partially delimits the electrode stack. A first part 2 of the first edge 1 is intended to be opposite a first lateral edge 35 of an electrical connecting bar 3 to electrically connect the electrochemical cell 10 to an adjacent electrochemical cell 10 in the battery module 20, battery pack 20, or electric battery 20.

[0025] One or more housings, or more generally, one or more support structures, are most often provided in the battery module 20, battery pack 20, or electric battery 20 to receive the electrochemical cell 10 such that the first edge portion 2 is aligned with the first lateral edge 35 of the electrical connecting bar 3. Here, the term "aligned" means that the first edge portion 2 is the portion of the first edge 1 closest to the electrical connecting bar 3 when the electrochemical cell 10 is arranged in the battery module 20, battery pack 20, or electric battery 20. In one embodiment, the first edge portion 2 has a length substantially equal to or slightly less than the length of the first lateral edge 35 of the electrical connecting bar 3, both lengths being measured in the direction of the first edge 1 of the electrochemical cell 10.

[0026] The electrochemical cell 10 further comprises a first electrical connection tab 4 of a first polarity. This first tab 4 forms, for example, the positive or negative electrical connection terminal of the electrochemical cell 10. The first electrical connection tab 4 protrudes or extends beyond the first edge 1. The first electrical connection tab 4 is intended to be connected to a first flat main face 36 of the electrical connection bar 3.

[0027] The first electrical connection tab 4 has a variable or different length (or depth) along the first edge portion 2. "Variable" or "different" indicates that this length is not constant, as highlighted, in particular, in Figure 1. This length is measured perpendicular to the first edge portion 2. In other words, the first tab 4 has a variable extent along the first edge portion 2 in a direction substantially perpendicular to the first edge portion 2.

[0028] The length of the first electrical connection tab 4 along the first edge portion 2 refers to its dimension extending beyond the first edge portion 2. The length of the first tab 4 varies along the first edge portion 2. More generally, the first electrical connection tab 4 is not uniformly long along the first edge portion 2.

[0029] A tab with a variable or different length along the first edge segment means that the distance of the tab, measured perpendicular to the first edge segment, varies at different points along this first edge segment. In other words, the first electrical connection tab does not have a uniform depth but exhibits variations in length along the first edge segment.

[0030] Advantageously, the first electrical connection tab 4 can have a length of zero at certain points along the first edge portion 2, as illustrated in Figure 1. For example, the first electrical connection tab 4 runs partially along the first edge portion 2, with the length of the first electrical connection tab 4 being zero along at least a portion of the first edge portion 2. By having a different length along the first edge portion 2, the contour of the first electrical connection tab 4 varies, creating, for example, a triangular shape, an L-shape, a pointed shape (a tab longer in the center and tapering towards the ends, as in Figure 1), a rectangular shape with at least one notch (cutout or notch), or a combination of these shapes.

[0031] In embodiments illustrated by figures 2 and 3, the first electrical connection tab4 comprises a section of substantially rectangular or triangular shape.

[0032] Advantageously, electrochemical cells 10, each incorporating a first electrical connection tab 4 of variable length along the corresponding first edge portion 2, allow for the arrangement, at the level of an electrical connecting bar 3, of electrical connecting tabs 4, 14 of complementary shapes (i.e., whose combination creates a complete and uniform geometric shape, in this case, a rectangle) or partially overlapping shapes. As will be detailed below, such arrangements of the electrical connecting tabs 4, 14 at the level of the electrical connecting bars 3 advantageously allow the use of compact electrical connecting bars 3 (in particular, narrower ones, this width being measured in a direction perpendicular to the first lateral edge 35 of the electrical connecting bar 3).Such arrangements of the electrical connection tabs 4,14 also make it possible to avoid an intermetallic mixture which may occur during simultaneous welding of the two electrical connection tabs 4,14 and the electrical connecting bar 3 which may compromise the quality of the electrical and mechanical connection between the electrochemical cells 10.

[0033] In one embodiment, the electrochemical cell 10 comprises a second edge 11 opposite the first edge 1, incorporating a second edge portion 12 intended to be aligned with a lateral edge of a second electrical connecting bar 3 for electrically connecting the electrochemical cell 10 to another adjacent electrochemical cell. A second electrical connecting tab 14 of a second polarity opposite to the first polarity protrudes from the second edge 11. This second electrical connecting tab 14 is intended to be connected to a second electrical connecting bar 3. The first tab 4 and the second electrical connecting tab 14 extend inward in the plane of the electrochemical cell 10.

[0034] In the embodiment illustrated in Figure 1, the first tab 4 has a first surface, and the second tab 14 has a second surface that is different from the first. In other words, the electrochemical cell 10 comprises a first tab 4 and a second tab 14 forming two electrical connection terminals of opposite polarity, the two tabs 4 and 14 having different surfaces. It follows that, when they are superimposed, one of the two electrical connection tabs 4 and 14 partially covers the other. In other words, when the first tab 4 and the second tab 14 are superimposed, they partially overlap, but not completely.Two tabs4,14 of the same surface, partially overlapping when superimposed on the same first main flat face36 of the electrical connecting bar3 (in particular, when they are of different shapes or are presented differently on the electrical connecting bar3), can also be considered.

[0035] In another embodiment illustrated in Figure 1, the second electrical connection tab 14 is substantially symmetrical to the first tab 4 with respect to a median plane 15 of the electrochemical cell 10. The median plane 15 is substantially perpendicular to the electrode stack. Such an arrangement of the electrical connection tabs 4 and 14 can advantageously be considered for a series connection of the electrochemical cells 10.

[0036] In another embodiment illustrated in Figure 1, the second electrical connection tab 14 is substantially symmetrical to the first electrical connection tab 4 with respect to a central axis 16 of the electrochemical cell. The central axis 16 is substantially perpendicular to the electrode stack. Such an arrangement of the electrical connection tabs 4, 14 can advantageously be considered for a parallel connection of the electrochemical cells 10.

[0037] Referring to the figure, a portion of a device 20 (in particular, a battery module 20, a battery pack 20, or an electric battery 20) is shown, comprising a plurality of electrochemical cells 10 arranged in a row (side by side along a connection direction) and whose electrical connection tabs 4, 14 are electrically connected to each other by means of electrical connecting bars 3. The electrochemical cells 10 are arranged in the device 20 so that their electrical connection tabs 4, 14 can be electrically connected to each other in a series or parallel arrangement using the electrical connecting bars 3 by laser welding.

[0038] The electrical connecting bar 3 comprises an elongated body made of an electrically conductive material (in particular, copper, aluminum, or an alloy thereof) extending between two adjacent electrochemical cells 10. The electrical connecting bar 3 has a first flat main face 36 and a second flat main face opposite the first flat face 36, connected by at least one first lateral edge 35 and a second lateral edge opposite the first lateral edge 35. The two flat main faces correspond to the largest surfaces of the electrical connecting bar 3, as opposed to the lateral edges, which are formed by the longitudinal and transverse edges. Each electrical connecting bar 3 allows the electrical contact of the electrical connection tabs 4, 14 of two successive electrochemical cells 10 in the battery module 20, battery pack 20, or electric battery 20. In an advantageous embodiment, the bar.The electrical connection bar is essentially flat, defined by two opposing main faces—the first main face and the second main face opposite it—which delimit a thin profile, the electrical connection bar extending primarily along a longitudinal plane. This configuration advantageously reduces size, weight, raw material consumption, and the number of manufacturing steps.

[0039] In one embodiment, at least one of the two electrical connection tabs 4,14 extends, when connected to the electrical connecting bar 3, beyond the mid-width (or half-width) of the electrical connecting bar 3 along at least a portion of the first edge 2. The mid-width of the electrical connecting bar 3 is measured in a direction perpendicular to its first lateral edge 35 and to its second lateral edge opposite the first lateral edge 35. Thus, a partial overlap or geometric complementarity of two tabs 4,14 can advantageously be achieved at the electrical connecting bar 3. Complementary or partially overlapping tabs 4,14 advantageously allow the use of a compact electrical connecting bar 3 and improve the weld quality of these tabs 4,14 to the electrical connecting bar 3.

[0040] As illustrated in Figures 5-6, the electrical connecting tabs 4,14 of two adjacent electrochemical cells 10 in a battery module 20, battery pack 20, or electric battery 20 are folded over the same flat principal face of the electrical connecting bar 3. At least one of the two electrical connecting tabs 4,14 has a variable length along the corresponding edge portion. In the example shown in Figure 1, only the electrical connecting tab 4 exhibits such a length variation. In the example in Figure 2, both electrical connecting tabs 4,14 have variable lengths along their corresponding edge portions. Each of the two electrical connecting tabs 4,14, when connected to the same principal face of the electrical connecting bar 3, extends beyond the mid-width of this electrical connecting bar 3 along at least a portion of the corresponding edge portion.Advantageously, due to the shape of one or both of the electrical connection tabs 4,14 and their arrangement on the electrical connection bar 3, an area of ​​one of the two electrical connection tabs 4,14 may not be covered by the other electrical connection tab 4,14. In other words, there is a non-overlap area between the two tabs 4,14 folded on the electrical connection bar 3.

[0041] To attach the electrical connection tabs 4, 14 to the electrical connecting bar 3, a first laser weld bead 31 (a dot or a line) is applied in a non-overlapping area of ​​the two tabs 4, 14 (an area where the two tabs do not overlap) so as to weld the tab corresponding to this area to the electrical connecting bar 3. In the example shown, the non-overlapping area is a region of the electrical connection tab 14 not covered by the electrical connection tab 4. In this case, the weld bead 31 allows the electrical connection tab 14 to be welded to the electrical connecting bar 3.

[0042] In one embodiment, a tab 4,14 of the first electrochemical cell 10 is made of a first material comprising a first metal. The electrical connecting bar 3 is made of a second material comprising the first metal. In other words, a tab 4,14 and the electrical connecting bar 3 share a common metal or both contain the same metal in their composition. This shared metal advantageously ensures better compatibility between the material of the tab 4,14 and the material of the electrical connecting bar 3, leading to improved structural integrity of the weld. This advantageously results in a reduction of the risk of cracking or weld defects and, consequently, a more robust and reliable first weld bead 31.

[0043] In one embodiment, the common metal is predominant in the material of the tab 4, 14 and in the material of the electrical connecting bar 3. The term "predominant metal in a material" refers to a compound that represents the largest quantity by weight among the compounds of the material; in other words, the compound constituting the main or most abundant component of the material in question. For example, the first tab 4 and the electrical connecting bar 3 are made of aluminum or copper, respectively, with different first and second purity levels.In this case, the tab 4 and the electrical connection bar 3 have similar melting and thermal expansion properties, promoting the creation of a first robust, reliable laser weld bead 31 without risks of weld defects and / or cracking that may occur when welding elements with different melting and / or thermal expansion properties.

[0044] Advantageously, a predominant common metal in the material of the tab 4,14 and in the material of the electrical connecting bar 3 enables a homogeneous and strong weld capable of withstanding the vibrations of the motor vehicle. This advantageously results in a stable and solid mechanical connection between the tab 4,14 and the electrical connecting bar 3. Applying the first weld bead 31 with suitable laser power to weld the tab 4,14 to the electrical connecting bar 3 allows, compared to welding the first tab 4, the second tab 14, and the electrical connecting bar 3 simultaneously, for their efficient assembly without the risk of creating a potential mixture of different materials.

[0045] More generally, applying a first weld bead 31 in the non-overlap zone of a tab 4,14 to fix it to the electrical connecting bar 3 provides mechanical stability to the connection between the electrochemical cells and the electrical connecting bars 3, particularly against vehicle vibrations. Since both are metallic elements, such a weld also allows, of course, an electrical connection between the tab 4,14 and the electrical connecting bar 3.

[0046] In the case of a partial overlap between the two tabs 4, 14 folded over the electrical connecting bar 3 (see), a second laser weld bead 32 can be applied in an overlapping area (where tab 4 is covered by tab 14 or vice versa) to weld the two tabs 4, 14 to each other. More generally, the device 20 includes, in one embodiment, a second laser weld bead 32 in an overlapping area between the two tabs 4, 14 so as to weld them to each other.

[0047] It should be noted that each of the first weld bead 31 and the second weld bead 32 does not require as much welding energy as welding both tabs 4, 14 and the electrical connecting bar 3 simultaneously. Excessive energy input to the weld can thus be avoided.

[0048] Advantageously, the embodiments described above prevent intermetallic mixing that could occur during welding of the second tab 14, the first tab 4, and the electrical connecting bar 3, and which could compromise the quality of the electrical and mechanical connection between the electrochemical cells 10. The weld beads 31, 32 securely attach the electrochemical cells 10 to the electrical connecting bar 3 and connect them electrically.

[0049] Furthermore, the need for a sufficiently wide electrical connection bar 3 to accommodate tabs 4, 14 on each side without overlap is advantageously no longer required. This results in a smaller footprint for the battery modules 20 (respectively, battery packs 20 or electric batteries 20), so that an increase in the number of electrochemical cells 10 per battery module 20 (respectively, per battery pack 20 or per electric battery 20) can be considered to improve the overall power of the vehicle.

Claims

Battery module (20) comprising: - a first electrochemical cell (10) incorporating a stack of electrodes separated from each other by a porous separator film, - an electrical connecting bar (3) for electrically connecting the first electrochemical cell (10) to a second electrochemical cell (10), adjacent to the first electrochemical cell (10), in said battery module (20), the electrical connecting bar (3) having a first main flat face, a second main flat face opposite the first face, connected by at least a first lateral edge and a second lateral edge opposite the first lateral edge; the first electrochemical cell (10) further incorporating a first edge (1) comprising a first part (2) of the edge opposite the first lateral edge of the electrical connecting bar (3);- a first electrical connection tab (4) extending beyond said first edge (1) intended to be connected to the first main face of the electrical connecting bar (3), this first electrical connection tab (4) having a variable length along the first part (2) of the edge, this length being measured perpendicular to the first part (2) of the edge; the first tab (4) extending, when connected to the first main face of the electrical connecting bar (3), beyond the mid-width of this electrical connecting bar (3) along at least a portion of the first part (2) of the edge, the mid-width of the electrical connecting bar (3) being measured in a direction perpendicular to said first lateral edge and second lateral edge.; Battery module according to the preceding claim, characterized in that the first tab (4) of the first electrochemical cell (10) is made of a first material comprising a first metal, the electrical bonding bar (3) being made of a second material comprising the first metal. Battery module according to the preceding claim, characterized in that the first metal is predominant in the first material and in the second material. Battery module according to any one of the preceding claims, characterized in that the first electrical connection tab (4) comprises a substantially rectangular or triangular shaped section. Battery module according to any one of the preceding claims, characterized in that the stack of electrodes is arranged in a flexible bag, the first electrochemical cell (4) further comprising an electrolyte in the bag. Battery module according to any one of the preceding claims, characterized in that the first electrochemical cell comprises: - a second edge (11) opposite the first edge (1); - a second electrical connection tab (14) extending from said second edge (11), this second tab (14) being substantially symmetric to the first tab (4) with respect to a median plane (15) of the first electrochemical cell (10) substantially perpendicular to the electrode stack or with respect to a central axis (16) of the first electrochemical cell (10) substantially perpendicular to the electrode stack. Battery module according to any one of the preceding claims, characterized in that it further comprises: a second electrochemical cell (10) adjacent to the first electrochemical cell in said battery module, this second electrochemical cell (10) incorporating a stack of electrodes separated from each other by a porous separator film; a third edge (1) comprising a third edge portion (2) opposite the second lateral edge of the electrical connecting bar (3); a third electrical connecting tab (4) protruding from said third edge (1) intended to be connected to the first main face of the electrical connecting bar (3); the third tab (4) extending, when connected to the first main face of the electrical connecting bar (3), beyond the mid-width of this electrical connecting bar (3) along at least a portion of the third edge portion (2);- a first laser weld bead (31) in a non-overlap zone of the first tab and the third tab so as to weld the tab corresponding to this zone to the electrical connecting bar (3). Battery module according to the preceding claim, characterized in that it further comprises a second laser weld bead (32) in an overlap zone between the first tab and the third tab, so as to weld the first tab to the third tab. Battery module according to any one of the preceding claims, characterized in that the electrical connecting bar is substantially flat in shape. Battery pack incorporating a plurality of (20) battery modules according to any one of the preceding claims. Electric battery (20) comprising: - a first electrochemical cell (10) incorporating a stack of electrodes separated from each other by a porous separating film, - an electrical connecting bar (3) for electrically connecting the first electrochemical cell (10) to a second electrochemical cell (10), adjacent to the first electrochemical cell (10), in said electric battery (20), the electrical connecting bar (3) having a first main flat face, a second main flat face opposite the first face, connected by at least a first lateral edge and a second lateral edge opposite the first lateral edge; the first electrochemical cell (10) further incorporating a first edge (1) comprising a first part (2) of the edge opposite the first lateral edge of the electrical connecting bar (3);- a first electrical connection tab (4) extending beyond said first edge (1) intended to be connected to the first main face of the electrical connecting bar (3), this first electrical connection tab (4) having a variable length along the first part (2) of the edge, this length being measured perpendicular to the first part (2) of the edge; the first tab (4) extending, when connected to the first main face of the electrical connecting bar (3), beyond the mid-width of this electrical connecting bar (3) along at least a portion of the first part (2) of the edge, the mid-width of the electrical connecting bar (3) being measured in a direction perpendicular to said first lateral edge and second lateral edge.; Electric battery (20) according to the preceding claim, characterized in that the first tab (4) of the first electrochemical cell (10) is made of a first material comprising a first metal, the electrical connecting bar (3) being made of a second material comprising the first metal. electric battery (20) according to the preceding claim, characterized in that the first metal is predominant in the first material and in the second material. Electric battery (20) according to any one of claims 11 to 13, characterized in that the first electrical connection tab (4) comprises a substantially rectangular or triangular shaped section. Electric battery (20) according to any one of claims 11 to 14, characterized in that the stack of electrodes is arranged in a flexible bag, the first electrochemical cell (4) further comprising an electrolyte in the bag. Electric battery (20) according to any one of claims 11 to 15, characterized in that the first electrochemical cell comprises - a second edge (11) opposite the first edge (1); - a second electrical connection tab (14) extending from said second edge (11), this second tab (14) being substantially symmetric to the first tab (4) with respect to a median plane (15) of the first electrochemical cell (10) substantially perpendicular to the electrode stack or with respect to a central axis (16) of the first electrochemical cell (10) substantially perpendicular to the electrode stack. Electric battery (20) according to any one of claims 11 to 16, characterized in that it further comprises: - a second electrochemical cell (10) adjacent to the first electrochemical cell in said electric battery (20), this second electrochemical cell (10) incorporating a stack of electrodes separated from each other by a porous separating film, a third edge (1) comprising a third edge portion (2) opposite the second lateral edge of the electrical connecting bar (3); a third electrical connecting tab (4) protruding from said third edge (1) intended to be connected to the first main face of the electrical connecting bar (3); the third tab (4) extending, when connected to the first main face of the electrical connecting bar (3), beyond the mid-width of this electrical connecting bar (3) along at least a portion of the third edge portion (2);- a first laser weld bead (31) in a non-overlap zone of the first tab and the third tab so as to weld the tab corresponding to this zone to the electrical connecting bar (3). electric battery (20) according to the preceding claim, characterized in that it further comprises a second laser weld bead (32) in an overlap zone between the first tab and the third tab, so as to weld the first tab to the third tab. Electric battery (20) according to any one of claims 11 to 18, characterized in that the electrical connecting bar is substantially flat in shape.

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