Electrode current collection tabs
The innovative design of current collection tabs with angled edges and fold lines addresses the issue of damage during transport, improving production efficiency by reducing creasing and snagging, thereby enhancing electrochemical cell production.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- VERKOR SA
- Filing Date
- 2024-05-23
- Publication Date
- 2026-04-24
AI Technical Summary
Rectangular current collection tabs in electrochemical cells have right-angled corners that are prone to bending, snagging, and damage during transport due to their weight and interaction with conveyor components, leading to production inefficiencies and increased defects.
The current collection tabs are designed with a distal portion featuring a second lateral edge that approaches the first lateral edge, avoiding a right angle, and may include a fold or pre-cut line to prevent snagging and damage, with shapes such as triangular, semi-circular, or rounded corners to reduce bending.
This design minimizes tab damage during transport, reducing defects and improving production efficiency by preventing creasing and snagging, thus enhancing the production rate of electrochemical cells.
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Abstract
Description
Title of the invention: Electrode current collection tabs
[0001] The present invention relates to the electrodes of electrochemical cells of prismatic or bag geometry and more particularly to the current collection tabs of such electrodes.
[0002] These electrodes are made from a metal foil (typically copper or aluminum) initially wound onto itself in the form of a coil. Once unwound, the metal foil is partially coated with an active material. A portion of the metal foil not coated with active material extends along a longitudinal edge of the foil. During a notching operation, current-collecting tabs are formed along the metal foil by cutting directly into the uncoated portion of the metal. These current-collecting tabs, devoid of active material, protrude from a longitudinal edge of the active portion.
[0003] Each of the current-collecting tabs is rectangular in shape, comprising a proximal portion bonded to the metal foil and intended to be electrically connected to a current collector, and a distal portion intended to receive a marking (an inscription, a code, or any other temporary identification mark during electrode manufacturing). The distal portion protrudes from the proximal portion. Once the proximal portion is welded to a current collector, the distal portion is removed during a deburring operation.
[0004] One disadvantage of these rectangular current collection tabs is that they have right-angled corners on their free edges opposite their attachment bases to the metal foil.
[0005] Indeed, given its length, a current-collecting tab extending horizontally from the electrode moving along a conveyor is liable, under its own weight, to bend downwards and possibly come into contact with a component of the conveyor or, more generally, with an obstacle. In the event of such contact, the right angle at the free edge of the current-collecting tab most often causes it to crease.
[0006] When encountering an obstacle in its path of travel, a right angle on the free edge of the current-collecting tab tends to act as an anchor point, causing damage to the current-collecting tab. In other words, the distinctive perpendicular aspect of the right angles on the free edge of the current-collecting tabs makes them susceptible to snagging or jamming when they encounter an obstacle during electrode transport.
[0007] More generally, rectangular current-collecting tabs having a proximal portion bonded to the metal foil and a distal portion protruding from it are subject to potential damage during electrode transport. When such damage occurs, the electrodes are discarded and the production lines are shut down, slowing down the production rate of electrochemical cells and reducing the overall plant output.
[0008] One object of the present invention is to remedy the aforementioned drawbacks.
[0009] Another object of the present invention is to avoid any risk of damage to the current collection tabs during the transport of electrodes intended for the manufacture of electrochemical cells of prismatic geometry or in sachets.
[0010] Another object of the present invention is to reduce the defects that may occur during the conveying of the electrode sheet on a conveyor and, consequently, to improve the production rate of electric battery cells.
[0011] To this end, it is proposed, firstly, an electrode comprising a metallic foil comprising - an active portion coated with an active material; - a metallic portion devoid of active material extending along a longitudinal edge of the metallic foil, this metallic portion comprising a current collection tab extending projecting from a longitudinal edge of the active portion; said current collection tab comprising - a proximal portion connected to the metallic sheet intended to be electrically connected to a current collector; - a distal portion intended to receive a marking, the distal portion protruding from the proximal portion; the distal portion comprising - a first lateral edge; - a second lateral border opposite the first lateral border, this second lateral border approaching, as it moves away from the proximal portion, the first lateral border.
[0012] Various additional features may be provided, alone or in combination: - the distal portion is triangular, semi-circular, semi-elliptical, trapezoidal, rectangular with one corner rounded, rectangular with two corners rounded on the same side, rectangular with one corner trimmed, rectangular with two corners trimmed on the same side, rectangular with one corner trimmed and one corner rounded on the same side; - the width of the current collection tab in the direction of the longitudinal edge of the metal foil is greater than half the length of the tab current collection, at two-thirds of the length of the current collection tab, or at three-quarters of the length of the current collection tab; - the distal portion includes a fold line or a pre-cut line; - the folding line or the pre-cutting line is connected to the first side edge and / or the second side edge.
[0013] Secondly, a method for manufacturing an electrode comprising a metallic foil comprising - an active portion coated with an active material; - a metallic portion devoid of active material extending along a longitudinal edge of the metallic foil, This process includes a cutting step in the metallic portion of a current-collecting tab extending projecting from a longitudinal edge of the active portion, this current-collecting tab comprising - a proximal portion connected to the metallic sheet intended to be electrically connected to a current collector; - a distal portion intended to receive a marking, the distal portion protruding from the proximal portion; - the cutting stage including - a first cut of a first lateral edge of the distal portion; - a second cut of a second lateral edge of the distal portion opposite the first lateral edge, this second lateral edge approaching, while moving away from the proximal portion, the first lateral edge.
[0014] Various additional features may be provided, alone or in combination: - the process presented above further includes a step of conveying the metal sheet, the second lateral edge being downstream, with respect to the direction of conveying the metal sheet, of the first lateral edge; -the distal portion is triangular, semi-circular, semi-elliptical, trapezoidal, rectangular rounded at one corner, rectangular rounded at two corners on the same side, rectangular with one corner trimmed, rectangular with two corners trimmed on the same side, rectangular with one corner trimmed and one corner rounded on the same side; - the process presented above further includes a step of creating a folding line or a pre-cutting line in the distal portion; - the folding line or the pre-cutting line is connected to the first side edge and / or the second side edge.
[0015] Other features and advantages of the invention will become more apparent and concrete upon reading the following description of embodiments, which is made with reference to the accompanying drawings in which:
[0016] Figure [Fig.1] schematically illustrates a metallic sheet according to various embodiments;
[0017] Figure [Fig.2] schematically illustrates a first embodiment of the metal sheet;
[0018] Figure [Fig.3] schematically illustrates a second embodiment of the metallic sheet;
[0019] Figure [Fig.4] schematically illustrates a third embodiment of the metallic sheet;
[0020] Figure [Fig.5] schematically illustrates a fourth embodiment of the metallic sheet;
[0021] Figure [Fig.6] schematically illustrates steps in a manufacturing process for an electrode comprising a metallic foil according to various embodiments.
[0022] In [Fig.1], a metallic sheet 1 is shown moving on a conveyor 2. This metallic sheet 1 has an active portion 3 coated with an active material and a metallic portion 4 without active material extending over a longitudinal edge of the metallic sheet 1.
[0023] A cutting (or notching) device 5 is configured to cut, in the metallic portion 4 devoid of active material, a current collection tab 6 extending in projection from a longitudinal edge 31 of the active portion 3 (or, equivalently, of the metallic sheet 1).
[0024] As illustrated in [Fig. 1], the current-collecting tab 6 comprises a proximal portion 61 connected to the metallic foil 1 intended to be electrically connected to a current collector and a distal portion 62 intended to receive a marking. The distal portion 62 protrudes from the proximal portion 61.
[0025] The distal portion 62 comprises a first lateral border 63 and a second lateral border 64 opposite the first lateral border 63, this second lateral border 64 approaching, as it moves away from the proximal portion 61, the first lateral border 63.
[0026] Advantageously, the particular shape of the second lateral edge 64 avoids the formation of a right angle which could act as a snagging or anchoring point causing damage to the current collection tab 6 when it encounters an obstacle during its movement on the conveyor 2. Consequently, less damage is caused to the current collection tab 6 during the conveying of electrodes intended for the manufacture of electrochemical cells of prismatic geometry or in a bag.
[0027] In embodiments, the distal portion 62 is triangular as illustrated in [Fig. 2], semicircular, semielliptical, trapezoidal as illustrated in [Fig. 3], rectangular with one corner rounded, rectangular with two corners rounded on the same side as illustrated in [Fig. 4], rectangular with one corner trimmed, rectangular with two trimmed corners on the same side, or rectangular with one trimmed corner and one rounded corner on the same side as illustrated by [Fig. 5]. Such shapes are, advantageously, easy to implement by the cutting device 5.
[0028] In another embodiment, the width of the current collection tab 6 in the direction of the longitudinal edge 31 of the active portion 3 is greater than half the length (in a direction perpendicular to the longitudinal edge 31 of the active portion 3) of the current collection tab 6, two-thirds of the length of the current collection tab 6, or three-quarters of the length of the current collection tab 6.
[0029] Such ratios between the dimensions of the current-collecting tab 6 advantageously prevent free bending of the current-collecting tab 6 under its own weight. Collision between the current-collecting tab 6 and an element of the conveyor 2 can thus be avoided.
[0030] In another embodiment, the distal portion 62 includes a fold line or a pre-cut line. This line may include weakening features such as slots or grooves to facilitate folding the distal portion 62. A fold line and / or a pre-cut line in the distal portion 62 advantageously absorbs the effect of a possible collision between the current-collecting tab 6 and an obstacle (in particular, a conveyor element) and thus prevents it from being crumpled.
[0031] In one embodiment, the fold line or pre-cut line is connected to the first lateral edge 63 and / or the second lateral edge 64. In other words, the fold or cut line includes a portion beginning or ending on the first lateral edge 63 and / or the second lateral edge 64. Depending on its direction, such a fold or pre-cut line allows for a preferred direction of deformation of the current collection tab 6 when it encounters an obstacle. Creasing of the current collection tab 6 can thus be avoided.
[0032] Referring to [Fig. 6], a method for manufacturing an electrode incorporating the metallic foil 1 comprises a cutting step 10, in the metallic portion 4, of a current-collecting tab 6 extending projecting from a longitudinal edge 31 of the active portion 3. This cutting step comprises a first cut of the first lateral edge 63 of the distal portion 62 and a second cut of the second lateral edge 64 of the distal portion 62 opposite the first lateral edge 63. Moving away from the proximal portion 61, the second lateral edge 64 moves closer to the first lateral edge 63 so as to avoid the formation of a right angle that could act as a snagging or anchoring point causing a damage to the current collection tab when it encounters an obstacle during its movement.
[0033] During the conveying (step 11 in [Fig. 6]) of the metal sheet 1, the second lateral edge 64 is downstream, with respect to the conveying direction 7 of the metal sheet 1, of the first lateral edge 63. Such an arrangement of the lateral edges 63, 64 of the distal portion 62 with respect to the conveying direction 7 involves the second lateral edge 64, which helps to reduce the risk of creasing the current-collecting tab 6 in the event of contact with an element of the conveyor 2 for conveying the metal sheet 1.
[0034] In one embodiment, the method for manufacturing an electrode incorporating the metallic sheet 1 further includes a step of creating 11 a bend line or a pre-cut line in the distal portion.
Claims
Demands
1. Electrode comprising a metallic foil (1) having - an active portion (3) coated with an active material; - a metallic portion (4) without active material extending over a longitudinal edge of the metallic foil, this metallic portion comprising a current-collecting tab (6) projecting from a longitudinal edge of the active portion (3); said current-collecting tab (6) comprising - a proximal portion (61) connected to the metallic foil (1) for electrical connection to a current collector; - a distal portion (62) comprising a fold line or a pre-cut line and for receiving a marking, said fold line or pre-cut line comprising weakenings such as slits or scratches for facilitating the folding of the distal portion (62), the distal portion (62) projecting from the proximal portion (61);this electrode being characterized in that the distal portion (62) comprises - a first lateral border (63); - a second lateral border (64) opposite the first lateral border, this second lateral border approaching, as it moves away from the proximal portion (61), the first lateral border (63).
2. Electrode according to the preceding claim, characterized in that the distal portion (62) is triangular, semi-circular, semi-elliptical, trapezoidal, rectangular rounded at one corner, rectangular rounded at two corners on the same side, rectangular with one corner trimmed, rectangular with two corners trimmed on the same side, rectangular with one corner trimmed and one corner rounded on the same side.
3. Electrode according to claim 1 or 2, characterized in that the width of the current-collecting tab (6) in the direction of the longitudinal edge of the metal foil is greater than half the length of the current-collecting tab (6), two-thirds the length of the current-collecting tab (6), or three-quarters the length of the current-collecting tab (6).
4. Electrode according to any one of the preceding claims, characterized in that the bend line or the pre-cut line is connected to the first lateral edge and / or the second lateral edge.
5. A method for manufacturing an electrode comprising a metallic foil (1) having - an active portion (3) coated with an active material; - a metallic portion (4) without active material extending over a longitudinal edge of the metallic foil, this method comprising a cutting step (10) in the metallic portion (4) of a current-collecting tab (6) extending projecting from a longitudinal edge (31) of the active portion (3), this current-collecting tab (6) comprising - a proximal portion (61) connected to the metallic foil (1) intended to be electrically connected to a current collector; - a distal portion (62) intended to receive a marking, the distal portion (62) projecting from the proximal portion (61); this method being characterized in that the cutting step comprises - a first cutting of a first lateral edge (63) of the distal portion;- a second cut of a second lateral edge (64) of the distal portion opposite the first lateral edge (63), this second lateral edge (64) approaching, while moving away from the proximal portion (61), the first lateral edge (63) - a step of creating (12) a fold line or a pre-cut line in the distal portion (62), said fold line or pre-cut line comprising weakenings such as slits or scratches intended to facilitate the folding of the distal portion (62).
6. Method according to the preceding claim, characterized in that it further comprises a conveying step (11) of the metal sheet (1), the second lateral edge (64) being downstream, with respect to the conveying direction (7) of the metal sheet (1), of the first lateral edge (63).
7. A method according to claim 5 or 6, characterized in that the distal portion (62) is triangular, semicircular, semielliptical, trapezoidal, rectangular with one corner rounded, rectangular with two corners rounded on the same side, rectangular with one corner trimmed, or rectangular with two corners trimmed on the same side.
8. rectangular side with one corner trimmed and one corner rounded on the same side. A method according to any one of claims 5 to 7, characterized in that the folding line or the pre-cutting line is connected to the first lateral edge (63) and / or the second lateral edge (64).