Battery cell for battery and method for manufacturing same

Abstract

A battery cell comprising at least one continuous stack of the following sheets: a first positive electrode (2) comprising an upper edge (4); -a first insulating separator; a second negative electrode (3) comprising a lower edge (5); and-a second insulating separator, said at least one stack being wound on itself about a central axis (Y) to form a cylinder, said first electrode (2) and said second electrode (3) each comprising at least two series (6) of current collector tabs (7), each series (6) comprising at least two current collector tabs (7) having a given height (9), in a given series (6) in the battery cell, the current collector tabs (7) have substantially the same height (9) and the height (9) of the current collector tabs (7) differs from one series (6) to another.

Description

Technical Field

[0001] This invention relates to the field of batteries for electric vehicles. In particular, this invention relates to battery cells. More specifically, this invention relates to cylindrical battery cells. Background Technology

[0002] Cylindrical battery cells are increasingly being used in the automotive industry.

[0003] The advantage of cylindrical battery cells lies in their ability to store a large amount of energy in a small volume. Therefore, for a given energy storage capacity, they take up less space in a vehicle.

[0004] The energy storage capacity of a cylindrical battery cell depends on its diameter. Therefore, the larger the diameter of a cylindrical battery cell, the greater its energy storage capacity.

[0005] Cylindrical battery cells are manufactured by continuously stacking at least the following components wound around a core:

[0006] - Positive electrode plate,

[0007] - Insulating separator plate,

[0008] - Negative electrode plate,

[0009] - Insulating separator plate.

[0010] Along the electrode plates, current-collecting tabs are added and then attached to the positive and negative electrode plates. These current-collecting tabs allow electrons to be directed, carrying current in the process. Although automated, this operation slows down the production speed of cylindrical battery cells. Furthermore, attachment and / or contact defects between the tabs and electrodes can degrade the performance of cylindrical battery cells or even cause short circuits.

[0011] To overcome these problems, some manufacturers have proposed eliminating the need for tabs and then attaching them to the electrodes.

[0012] One such solution involves cutting directly onto an electrode sheet that is not coated with active material to form current-collecting tabs before winding it around a rotating mandrel. After winding, these tabs are bent and brought into contact with the added current collector.

[0013] One drawback of this method is the difficulty in bending the tabs, partly due to the large number of tabs. Furthermore, attaching tabs at bent locations is cumbersome and technically challenging when the goal is to achieve industrial production speeds.

[0014] By eliminating the need for tabs, it is important to ensure that the cutting performed on the electrode sheet allows for a near-certain achievement of the given architecture; otherwise, manufacturers risk producing defective products that could impair the performance of their production lines.

[0015] Therefore, one drawback of cutting electrode sheets is that it is particularly difficult to obtain rows where the tabs are almost certainly aligned. When the tabs are misaligned in the tab row, this can reduce the performance of the battery cell.

[0016] Therefore, the present invention aims to solve the problems mentioned above. Summary of the Invention

[0017] Therefore, the present invention first provides a battery cell for an electrically driven vehicle, the battery cell comprising at least one continuous stack of the following sheets:

[0018] - Including the first positive electrode at the upper edge,

[0019] - First insulating separator,

[0020] - Including the second negative electrode at the lower edge,

[0021] - Second insulating separator,

[0022] The at least one stack is wound around a central axis to form a cylinder. The first electrode and the second electrode each include at least two series of current-collecting tabs, each series including at least two current-collecting tabs. Each current-collecting tab extends from the upper edge to the upper vertex in the first electrode and from the lower edge to the lower vertex in the second electrode at a given height measured along the central axis. Within the battery cell, the current-collecting tabs in a given series have substantially the same height, and the height of the current-collecting tabs differs from one series to another. Within the battery cell, the current-collecting tabs in a given series have a third length measured along a first axis, which is substantially perpendicular to the central axis and parallel to the upper and lower edges.

[0023] In a battery cell, the first separation distance between two current-collecting tabs of a given series is the same and varies from one series to another.

[0024] In a battery cell, within a given series, the third length is between 50% and 150% of the first distance.

[0025] This ensures that the tabs are almost certainly arranged one behind the other. In fact, this architecture is particularly difficult to achieve. In a given row of 20 tabs, angular misalignment between the tabs often occurs. These misalignments often cause tabs that should be in the same row of 20 to no longer overlap, resulting in the risk that electrical connection between them is no longer permitted once folded, which impairs the performance of the battery cell and may even require its disposal. By utilizing such a first distance 22 and a third length 30, such angular misalignment in a given row of 20 can be avoided. In particular, this almost certainly guarantees that each tab in a given row of 20 has at least 50% surface area overlap with the adjacent (one or more) tab(s). This overlap is sufficient to ensure effective electrical contact and prevent the battery cell from being discarded.

[0026] Various additional features can be provided individually or in combination:

[0027] - In a given series, the third length is between 80% and 120% of the first distance;

[0028] - In a given series, the first distance is approximately equal to the third length;

[0029] - The height of the current collecting tab decreases as it moves along the first and second electrodes in the winding direction;

[0030] - Once the stack is wound around itself around the central axis, the battery cell includes multiple rows of current collecting tabs that extend from the periphery of the battery cell toward the center of the battery cell located on the central axis;

[0031] - The height of the current collecting tab decreases as it moves from the periphery toward the center;

[0032] - As the first and second electrodes move along the winding direction, the first distance decreases from one series to another;

[0033] - The current collecting tabs that separate two adjacent series and the second distance measured along the first axis change as the electrode moves along the first and second electrodes;

[0034] - The second distance decreases as the first and second electrodes are moved in the winding direction;

[0035] - The current collecting tab has an isosceles trapezoidal shape;

[0036] - Current collecting tabs include:

[0037] - An upper first bottom that coincides with the upper edge of the first electrode and a lower first bottom that coincides with the lower edge of the second electrode.

[0038] - The upper second bottom that coincides with the upper vertex of the current collecting electrode and the lower second bottom that coincides with the lower vertex of the current collecting electrode.

[0039] - Connect the upper first bottom to the two upper sides of the upper second bottom and connect the lower first bottom to the two lower sides of the lower second bottom;

[0040] - The first base has a first length and the second base has a second length less than the first length, the first length and the second length being measured along the first axis;

[0041] - The first length and the second length have a ratio between 1 and 2;

[0042] - The current collecting tab has a basic rectangular shape;

[0043] - The third length differs from one series to another;

[0044] - The third length decreases as it moves along the winding direction;

[0045] - Each current collecting tab includes a cut along a central axis that divides each current collecting tab into two half-tabs of substantially the same size;

[0046] - In the first electrode, the cut extends from the upper edge to the upper vertex, while in the second electrode, the cut extends from the lower edge to the lower vertex;

[0047] - From one series to the next, the change in the first distance is roughly equal to the change in the third length. Attached Figure Description

[0048] Further features and advantages of the present invention will become clear from the following detailed description, in which reference is made to the accompanying drawings, wherein:

[0049] Figure 1 This is a schematic representation of the electrodes according to the present invention.

[0050] Figure 2 This is a schematic representation of the electrodes according to an alternative embodiment.

[0051] Figure 3 This is a schematic representation of the electrodes according to an alternative embodiment.

[0052] Figure 4 This is a schematic representation of the electrodes according to an alternative embodiment.

[0053] Figure 5 This is a schematic representation of a battery cell according to the present invention. Detailed Implementation

[0054] Figure 5 A rechargeable battery cell 1 for an electric vehicle is shown. The battery cell 1 comprises at least one continuous stack of the following sheets:

[0055] - First positive electrode 2,

[0056] - First insulating separator (not shown in the figure).

[0057] - Second negative electrode 3,

[0058] - Second insulating separator (not shown in the figure).

[0059] The first electrode 2 includes an upper edge 4. The second electrode 3 includes a lower edge 5.

[0060] In the remainder of this disclosure, and without limitation—nor as reference to Earth's gravity—the longitudinal, transverse, and vertical orientations are defined according to the X, Y, and Z trihedrons shown in the figure, wherein:

[0061] - The X-axis corresponds to the first vertical axis, which is parallel to the top and bottom edges.

[0062] - The Y-axis, which is perpendicular to the X-axis, corresponds to the central axis around which the battery cells are wound.

[0063] - The Z-axis, which is perpendicular to the X and Y axes, corresponds to the second horizontal axis.

[0064] The trihedron XYZ defines the planes XY, XZ, and YZ.

[0065] As mentioned earlier, the stacks are rolled up around the Y-axis. The rolled-up stacks form a cylinder.

[0066] The first electrode plate 2 and the second electrode plate 3 each include at least two series 6 of current collecting tabs 7. Each series 6 includes at least two current collecting tabs 7. In the embodiment shown in the figure, the first electrode plate 2 includes three series 6 and each series 6 includes four current collecting tabs 7, but this is not a limitation.

[0067] In the first electrode plate 2, each current collecting tab 7 extends from the upper edge 4 to the upper vertex 8 at a given height. In the second electrode plate 3, each current collecting tab 7 extends from the lower edge 5 to the lower vertex 10 at a given height 9. Height 9 is measured along the Y-axis.

[0068] In a given series 6 of current collecting tabs 7, all current collecting tabs 7 have the same height 9.

[0069] However, the height 9 of the current collecting tab 7 differs between series 6. Specifically, in the first series 11, the current collecting tab 7 has a first height 16. In the second series 12, the current collecting tab 7 has a second height 17 greater than the first height 16. In the third series 13, the current collecting tab 7 has a third height 18 greater than the second height 17.

[0070] Once the stack has been wound around the Y-axis, the current collecting tabs 7 overlap each other. The current collecting tabs 7 bend from the periphery 14 of the cell 1 toward the center 15 of the cell 1.

[0071] exist Figure 1 In a given series 6, the current collecting tab 7 has a given third length 30 measured along the X-axis. Therefore, in a given series 6, the current collecting tab 7 has the same third length 30.

[0072] The first separation distance 22 between the two current collecting tabs 7 of a given series 6 is substantially the same. The first distance 22 is measured along the X-axis.

[0073] The first distance 22 is different between series.

[0074] The third length 30 is between 50% and 150% of the first distance 22.

[0075] This ensures that the tabs are almost certainly arranged one behind the other. In fact, this architecture is particularly difficult to achieve. In a given row of 20 tabs, angular misalignment between the tabs frequently occurs. These misalignments mean that if tabs that should be in the same row of 20 no longer overlap, there is a risk that once folded, electrical connection between them will no longer be permitted, which impairs the performance of the battery cell and may even require its scrapping. By using such a first distance 22 and a third length 30, the existence of such angular misalignment in a given row of 20 can be avoided. In particular, this almost certainly guarantees that each tab in a given row of 20 has at least 50% surface area overlap with the adjacent (one or more) tab(s). This overlap is sufficient to ensure effective electrical contact and prevent the battery cell from being scrapped.

[0076] Advantageously, the third length 30 is between 80% and 120% of the first distance 22.

[0077] This almost certainly guarantees that each tab in a given row of 20 has at least 50% surface area overlap with the adjacent (one or more) tabs.

[0078] Advantageously, in a given series, the first distance 22 is substantially equal to the third length 30. Using such a first distance 22 and third length 30, this angular misalignment in a given row 20 can be avoided. Furthermore, it simplifies the manufacturing process and avoids production waste.

[0079] Advantageously, the height 9 of the current collecting tab 7 decreases as it moves along the first electrode 2 and the second electrode 3 in the winding direction 19.

[0080] This makes it easier to bend the current collecting tab 7. In fact, the current collecting tab 7, with a minimum height 9, is therefore located close to the Y-axis of the battery cell. When bent, metal clusters can be avoided near the Y-axis, thus simplifying the assembly of the battery cell 1.

[0081] Advantageously, and with reference Figure 5 Unit 1 includes several rows 20 of current collecting tabs 7. The rows 20 extend from the periphery 14 of the battery unit 1 toward the center 15 of the battery unit 1, which is located on the Y-axis.

[0082] Advantageously, the height 9 of the current collecting tab 7 decreases as it moves from the periphery 14 toward the battery center 15 of cell 1.

[0083] This makes bending the current collection tab 7 easier and neater. In fact, the bending of the current collection tab 7 is more coordinated. This prevents the formation of uncontrolled metal clusters at the end 21 of the battery cell 1. This reduces the risk of short circuits, electrolyte leakage, and accidents.

[0084] Advantageously, as the first electrode 2 and the second electrode 3 move along the winding direction 19, the first distance 22 decreases from one series 6 to the next series.

[0085] This produced things such as Figure 5 The desired pattern shown. In fact, it makes sense for the first distance 22 to differ from one series 6 to another to accommodate the position of a given series 6 within the cylinder.

[0086] Advantageously, a second distance 23 separates the current collecting tabs 7 of two adjacent series 6. The second distance 23 is measured along the X-axis. The second distance 23 changes as the electrode moves along the first electrode 2 and the second electrode 3. This produces effects such as Figure 2 The desired pattern shown. In fact, it makes sense for the second distance 23 to evolve from one series 6 to another to accommodate the position of a given series 6 within the cylinder.

[0087] Advantageously, the second distance 23 decreases as the electrode 2 moves along the first electrode 2 and in the winding direction 19. This produces effects such as Figure 5The desired pattern shown. In fact, it makes sense for the second distance 23 to decrease along the winding direction 19 from one series 6 to the next to accommodate the position of a given series 6 in the cylinder.

[0088] Advantageously, and according to Figure 2 In the embodiment shown, the current collecting tab 7 has an isosceles trapezoidal shape.

[0089] This shape makes it easier to bend the current collecting tab 7.

[0090] Advantageously, each current collecting tab 7 includes:

[0091] - The upper first bottom 24 that coincides with the upper edge 4 of the first electrode 2 and the lower first bottom 25 that coincides with the lower edge 5 of the second electrode 3.

[0092] - The upper second bottom 26 that coincides with the upper vertex 8 of the first electrode 2 and the lower second bottom 27 that coincides with the lower vertex 10 of the second electrode 3.

[0093] - Connecting the upper first bottom 24 to the two upper sides 32 of the upper second bottom 26, and connecting the lower first bottom 25 to the two lower sides 33 of the lower second bottom 27.

[0094] Advantageously, the first bases 24 and 25 have a first length 28 measured along the X-axis, and the second bases 26 and 27 have a second length 29 measured along the X-axis. The second length 29 is shorter than the first length 28.

[0095] Therefore, an isosceles trapezoid shape can be obtained.

[0096] Advantageously, the first length 28 and the second length 29 have a ratio between 1 and 2. This ratio is calculated by dividing the first length 28 by the second length 29.

[0097] The inventors have determined that the ratio within this range is particularly advantageous because it promotes bending of the current collecting tab 7 by avoiding the formation of metal clusters.

[0098] Advantageously, and according to Figure 1 In the embodiment shown, the collecting tab 7 has a basic rectangular shape.

[0099] Advantageously, from one series 6 to another, the third length 30 is different.

[0100] This makes it possible to obtain, such as Figure 5 The desired pattern shown is one that responds to technical considerations.

[0101] Advantageously, the third length 30 decreases as the winding direction 19 is moved.

[0102] Advantageously, according to Figure 3 and Figure 4 In the alternative embodiment shown, each current collecting tab 7 includes a cut 31 along the Y-axis. The cut 31 divides each current collecting tab 7 into two half-tabs having substantially the same size.

[0103] This makes bending the current collecting tab 7 easier, as bending the half-tab has proven to be a less complicated operation.

[0104] Advantageously, in the first electrode 2, the cut 31 extends from the upper edge 4 to the upper vertex 8. In the second electrode 3, the cut 31 extends from the lower edge 5 to the lower vertex 10.

[0105] This prevents the formation of metal clusters at the base of the current collecting tab 7. It also prevents the formation of ripples on the current collecting tab 7 when the electrodes are wound.

[0106] Advantageously, from one series 6 to the next, the change in the first distance 22 is essentially equal to the change in the third length 30. In other words, and for example, when the first distance 22 increases by 1 mm from one series to the next, the third length 30 also increases by 1 mm.

[0107] By using such a first distance 22 and a third length 30, angular misalignment in a given row 20 can be avoided.

Claims

1. A battery cell (1) for an electrically driven vehicle, said battery cell (1) comprising at least one continuous stack of the following sheets: - Including the first positive electrode (2) at the upper edge (4). - First insulating separator, - Including the second negative electrode (3) at the lower edge (5). - Second insulating separator, The at least one stack is wound around itself around a central axis (Y) to form a cylinder. The first electrode (2) and the second electrode (3) each include at least two series (6) of current collecting tabs (7), each series (6) including at least two current collecting tabs (7). Each current collecting tab (7) extends from the upper edge (4) to the upper vertex in the first electrode (2) and from the lower edge (5) to the lower vertex (10) in the second electrode (3) at a given height (9) measured along the central axis (Y). In the battery cell (1), the current collecting tabs (7) in a given series (6) have substantially the same height (9), and the height (9) of the current collecting tabs (7) is different from one series (6) to another. The current collecting tabs (7) of a given series (6) in the battery cell (1) have a third length (30) measured along a first axis (X), which is substantially perpendicular to the central axis (Y) and parallel to the upper and lower edges (4, 5). In a given series (6) of the battery cell, the first separation distance (22) between the two current collecting tabs is the same and varies from one series to another. In the battery cell, in a given series (6), the third length (30) is between 50% and 150% of the first distance (22).

2. The battery cell according to the preceding claim, wherein, In a given series (6), the third length (30) is between 80% and 120% of the first distance (22).

3. The battery cell (1) according to any one of the preceding claims, wherein, In a given series (6), the first distance (22) is approximately equal to the third length (30).

4. The battery cell (1) according to any one of the preceding claims, wherein, As the current collecting tab (7) moves along the first electrode (2) and the second electrode (3) in the winding direction (19), the height (9) of the current collecting tab (7) decreases.

5. The battery cell (1) according to any one of the preceding claims, wherein, Once the stack is wound around the central axis (Y), the battery cell (1) includes multiple rows (20) of current collecting tabs (7) extending from the periphery (14) of the battery cell (1) toward the center (15) of the battery cell (1) located on the central axis (Y).

6. The battery cell (1) according to claim 5, wherein, As the current collecting tab (7) moves from the periphery (14) toward the center (15), the height (9) of the current collecting tab (7) decreases.

7. The battery cell (1) according to any one of the preceding claims, wherein, As the first electrode (2) and the second electrode (3) move along the winding direction (19), the first distance (22) decreases from one series (6) to another.

8. The battery cell (1) according to any one of the preceding claims, wherein the current collecting tabs (7) separating two adjacent series (6) and the second distance (23) measured along the first axis (X) change as the battery cell moves along the first electrode (2) and the second electrode (3).

9. The battery cell (1) according to claim 8, wherein, The second distance (23) decreases as the first electrode (2) and the second electrode (3) move along the winding direction (19).

10. The battery cell (1) according to any one of the preceding claims, wherein the current collecting tab (7) has an isosceles trapezoidal shape.

11. The battery cell (1) according to claim 10, wherein the current collecting tab (7) comprises: - The upper first bottom (24) that coincides with the upper edge (4) of the first electrode (2) and the lower first bottom (25) that coincides with the lower edge (5) of the second electrode (3). - The upper second bottom (26) that coincides with the upper vertex (8) of the current collecting electrode (7) and the lower second bottom (27) that coincides with the lower vertex (10) of the current collecting electrode (7). - Connect the upper first bottom (24) to the two upper sides (32) of the upper second bottom (26) and connect the lower first bottom (25) to the two lower sides (33) of the lower second bottom (27).

12. The battery cell (1) according to claim 11, wherein the first base (24, 25) has a first length (28) and the second base (26, 27) has a second length (29) less than the first length (28), the first length (28) and the second length (29) being measured along a first axis (X).

13. The battery cell (1) according to claim 12, wherein the first length (28) and the second length (29) have a ratio between 1 and 2.

14. The battery cell (1) according to any one of the preceding claims, wherein the current collecting tab (7) has a generally rectangular shape.

15. The battery cell (1) according to any one of the preceding claims, wherein, From one series (6) to another, the third length (30) is different.

16. The battery cell (1) according to any one of the preceding claims, wherein, The third length (30) decreases as the device moves along the winding direction (19).

17. The battery cell (1) according to any one of the preceding claims, wherein each current collecting tab (7) includes a cut (31) along a central axis (Y) that divides each current collecting tab (7) into two half-tabs having substantially the same size.

18. The battery cell (1) according to claim 17, wherein, In the first electrode (2), the cut (31) extends from the upper edge (4) to the upper vertex (8), while in the second electrode (3), the cut (31) extends from the lower edge (5) to the lower vertex (10).

19. The battery cell (1) according to any one of the preceding claims, wherein, From one series (6) to the next, the change in the first distance (22) is roughly equal to the change in the third length (30).

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