Cell for battery and method for manufacturing the same

Abstract

The present invention relates to a battery cell comprising at least one continuous laminate comprising: a sheet of a first positive electrode (2) including an upper edge (4); a sheet of a first insulating separator; a sheet of a second negative electrode (3) including a lower edge (5); and a sheet of a second insulating separator, wherein the at least one laminate is wound around itself around a central axis (Y) to form a cylinder, and the first electrode (2) and the second electrode (3) each include at least two groups (6) of current collector tabs (7), each group (6) includes at least two current collector tabs (7) having a predetermined height (9), and within the same group (6), the current collector tabs (7) have substantially the same height (9), and the height (9) of the current collector tabs (7) differs from each other between the groups (6).

Description

Technology Field

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

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

[0003] The advantage of cylindrical cells is that they can store a large amount of energy within a small volume.

[0004] Therefore, it occupies less space within the vehicle for the same energy storage capacity.

[0005] The energy storage capacity of a cylindrical cell depends on its diameter. In other words, the larger the diameter of the cylindrical cell, the greater its energy storage capacity.

[0006] A cylindrical cell is manufactured by winding a sheet containing at least the following around a mandrel:

[0007] - Positive electrode sheet,

[0008] - Insulating separator sheet,

[0009] - Cathode electrode sheet,

[0010] - Insulating separator sheet.

[0011] After a current collection tab is added along the electrode sheet, it is attached to the positive and negative electrode sheets. This current collection tab channels electrons to allow current to flow. Even if this process is automated, it reduces the production speed of the cylindrical cell. In addition, attachment and / or contact defects between the tab and the electrode can degrade the performance of the cylindrical cell and even cause a short circuit.

[0012] To solve this problem, some manufacturers proposed a solution to eliminate the tab attached to the electrode after addition.

[0013] One such solution is to form current collector tabs by creating incisions directly in the electrode sheet region that is not coated with active material before winding around the rotating mandrel. After winding, these tabs are folded to come into contact with an added current collector.

[0014] One of the disadvantages of this method is that bending the tabs is difficult due to the large number of tabs. Additionally, attaching the tabs at the bent positions is cumbersome and technically challenging when aiming to achieve industrial production speeds.

[0015] When eliminating the need for tab insertion, it is important to ensure that the incision formed in the electrode sheet almost certainly implements a specific architecture; otherwise, the manufacturer risks producing defective products, which impairs the performance of the production line.

[0016] Therefore, one of the disadvantages of cutting the electrode sheet is that it is particularly difficult to obtain rows where the tabs are almost certainly aligned. If the tabs are not aligned in the tab rows, cell performance is highly likely to degrade.

[0017] The present invention aims to solve the above problems.

[0018] To this end, the present invention first provides a battery cell for an electric propulsion vehicle, said cell being:

[0019] - A first positive electrode sheet including an upper edge,

[0020] - 1st insulation separator sheet,

[0021] - A second cathode electrode sheet including a lower edge,

[0022] - Second insulation separator sheet

[0023] It includes at least one continuous stack of,

[0024] The above at least one laminate is wound around itself about a central axis to form a cylinder, and the first electrode and the second electrode each include at least two series of current collector tabs, each series including at least two current collector tabs, and each current collector tab extends over a predetermined height measured along the central axis from the upper edge to the upper apex in the first electrode and from the lower edge to the lower apex in the second electrode.

[0025] In the cell above, the current collector taps within a specific group have substantially the same height, and the heights of the current collector taps differ from group to group, and in the cell above, the current collector taps of a specific group have a third length measured along a first axis that is substantially perpendicular to the central axis and parallel to the upper and lower edges, and

[0026] In the above cell, the first separation distance (separation distance) between two current collector taps of a specific group is the same and varies between groups, and

[0027] In the cell above, the third length in a specific group is 50% to 150% of the first distance.

[0028] This ensures that the tabs are almost certainly arranged in a continuous sequence back and forth. In practice, this architecture is particularly difficult to implement. Angle misalignment (angle misalignment) between tabs within the same tab row (20) frequently occurs. Due to this misalignment, tabs that should be in the same row often no longer overlap each other; in this case, there is a risk that electrical connection between them will no longer be possible after bending, which can degrade cell performance and even lead to disposal. By setting the first distance and the third length as described above, the occurrence of such angle misalignment within the same tab row (20) can be prevented. In particular, this almost certainly ensures that each tab in the same row (20) has a surface area that overlaps with the adjacent tab(s) by more than 50%. This overlap is sufficient to ensure effective electrical contact and prevent cell disposal.

[0029] The following additional features may be provided individually or in combination.

[0030] - In a specific group, the third length is 80% to 120% of the first length.

[0031] - In a specific group, the first distance is substantially the same as the third length.

[0032] - The height of the current collector tap decreases as it moves in the winding direction along the first and second electrodes.

[0033] - After the laminate is wound around itself around a central axis, the cell includes a plurality of rows of current collector taps, said rows extending from the periphery of the cell toward the center of the cell located on the central axis.

[0034] - The height of the current collector tap decreases as it moves from the periphery toward the center.

[0035] - The first distance decreases between groups as it moves along the first electrode and the second electrode in the winding direction.

[0036] - The second distance separating two adjacent groups, measured along the first axis, changes as it moves along the first electrode and the second electrode.

[0037] - The second distance decreases as it moves in the winding direction along the first and second electrodes.

[0038] - The current collector tap is an isosceles trapezoidal shape.

[0039] - The current collector tap is:

[0040] - A first upper base aligned with the upper edge of the first electrode and a first lower base aligned with the lower edge of the second electrode,

[0041] - A second upper base corresponding to the upper apex of the current collector tap and a second lower base corresponding to the lower apex of the current collector tap,

[0042] - Includes two upper side edges connecting the first upper base to the second upper base and two lower side edges connecting the first lower base to the second lower base.

[0043] - The first base has a first length and the second base has a second length that is smaller than the first length, and the first length and the second length are measured along the first axis.

[0044] - The ratio of the first length to the second length is 1 to 2.

[0045] - The current collector tap is practically rectangular in shape.

[0046] - The above third lengths differ between the groups.

[0047] - The above third length decreases as it moves in the winding direction.

[0048] - Each current collector tap includes a cut along the central axis, and said cut separates each current collector tap into two half-tabs of substantially the same size.

[0049] - In the first electrode, the incision extends from the upper edge to the upper apex, and in the second electrode, the incision extends from the lower edge to the lower apex.

[0050] - The change in the first distance between groups is approximately the same as the change in the third length. Brief explanation of the drawing

[0051] Further features and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings, in which: - FIG. 1 is a schematic diagram of an electrode according to the present invention, and - FIG. 2 is a schematic diagram of an electrode according to an alternative embodiment, and - FIG. 3 is a schematic diagram of an electrode according to an alternative embodiment, and - FIG. 4 is a schematic diagram of an electrode according to an alternative embodiment, and - FIG. 5 is a schematic diagram of a cell according to the present invention. Specific details for implementing the invention

[0052] FIG. 5 illustrates a rechargeable battery cell (1) for an electric propulsion vehicle. The cell (1) is,

[0053] - Sheet of the first positive electrode (2),

[0054] - Sheet of the first insulating separator (not shown in the drawing),

[0055] - Sheet of the second negative electrode (3),

[0056] - Sheet of the second insulation separator (not shown in the drawing)

[0057] It includes at least one continuous laminate composed of

[0058] The first electrode (2) includes an upper edge (4). The second electrode (3) includes a lower edge (5).

[0059] In the following description, longitudinal, transverse, and vertical directions are defined without limitation (and without reference to Earth's gravity) according to the X, Y, Z trihedral coordinate system depicted in the drawings, where:

[0060] - The X-axis corresponds to the first longitudinal axis parallel to the upper and lower edges, and

[0061] - The Y-axis, perpendicular to the X-axis, corresponds to the center axis of the cell where the laminate is wound, and

[0062] - The Z-axis, which is perpendicular to the X-axis and Y-axis, corresponds to the second horizontal axis.

[0063] The XYZ coordinate system defines the XY, XZ, and YZ planes.

[0064] As described above, the laminate is wound around itself around the Y-axis. The wound laminate forms a cylinder.

[0065] The first electrode sheet (2) and the second electrode sheet (3) each include at least two groups (6) of current collector taps (7). Each group (6) includes at least two current collector taps (7). In the embodiment illustrated in the drawing, the first electrode sheet (2) includes three groups (6), and each group (6) includes four current collector taps (7), but is not limited thereto.

[0066] In the first electrode sheet (2), each current collector tap (7) extends over a predetermined height from the upper edge (4) to the upper apex (8). In the second electrode sheet (3), each current collector tap (7) extends over a predetermined height (9) from the lower edge (5) to the lower apex (10). The height (9) is measured along the Y-axis.

[0067] All current collector taps (7) in the same group (6) have the same height (9).

[0068] However, the height (9) of the current collector tap (7) differs between the groups (6). That is, in the first group (11), the current collector tap (7) has a first height (16). In the second group (12), the current collector tap (7) has a second height (17) which is greater than the first height (16). In the third group (13), the current collector tap (7) has a third height (18) which is greater than the second height (17).

[0069] After the laminate is wound around the Y-axis, the current collector tabs (7) are folded upward and stacked on top of each other. The current collector tabs (7) are folded from the periphery (14) of the cell (1) toward the center (15) of the cell (1).

[0070] In FIG. 1, the current collector tap (7) in the same group (6) has a predetermined third length (30) measured along the X-axis. That is, the current collector tap (7) in the same group (6) has the same third length (30).

[0071] In the same group (6), the first separation distance (22) between the two current collector taps (7) is substantially the same. The first distance (22) is measured along the X-axis.

[0072] The first distance (22) is different between the groups (6).

[0073] The third length (30) is 50% to 150% of the first distance (22).

[0074] This ensures that the tabs are almost certainly positioned following one another. In practice, this architecture is particularly difficult to implement. Angle misalignment between tabs frequently occurs within the same row of tabs (20). Due to this misalignment, tabs that should be in the same row (20) frequently do not overlap each other; in this case, there is a risk that electrical connection will no longer be possible after bending, which can degrade cell performance and even lead to disposal. By such a first distance (22) and third length (30), the occurrence of such angle misalignment within the same row (20) can be prevented. In particular, this almost certainly ensures that each tab in the same row (20) has at least 50% of its surface area overlap with adjacent tab(s). This overlap is sufficient to ensure effective electrical contact and prevent cell disposal.

[0075] Preferably, the third length (30) is 80% to 120% of the first distance (22).

[0076] This almost certainly ensures that each tab in the same row (20) has at least 50% of its surface area overlap with the adjacent tab(s).

[0077] Preferably, in the same group, the first distance (22) is substantially the same as the third length (30). With such first distance (22) and third length (30), the occurrence of angle misalignment in the same row (20) can be prevented. In addition, the manufacturing method is simplified and production defects (scrap) are prevented.

[0078] Preferably, the height (9) of the current collector tap (7) decreases as it moves along the first electrode (2) and the second electrode (3) in the winding direction (19).

[0079] This facilitates the bending of the current collector tap (7). That is, the current collector tap (7) having the smallest height (9) is positioned near the Y-axis of the cell. This avoids the formation of metal clusters near the Y-axis during bending, thereby simplifying the assembly of the cell (1).

[0080] Preferably, with reference to FIG. 5, the cell (1) includes a plurality of current collector tap rows (20). The rows (20) extend from the periphery (14) of the cell (1) toward the center (15) of the cell (1), said center (15) is located on the Y-axis.

[0081] Preferably, the height (9) of the current collector tap (7) decreases as it moves from the periphery (14) of the cell (1) toward the center (15).

[0082] This makes the bending of the current collector tap (7) easier and cleaner. That is, the tap bending is performed more harmoniously. This prevents the formation of uncontrolled metal clusters at the end (21) of the cell (1). As a result, the risk of short circuits, electrolyte leakage, and accidents is reduced.

[0083] Preferably, the first distance (22) decreases between groups (6) as it moves along the first electrode (2) and the second electrode (3) in the winding direction (19).

[0084] This creates a desired pattern as illustrated in FIG. 5. In practice, to match the position of a specific group (6) within the cylinder, it is desirable that the first distance (22) be different between the groups (6).

[0085] Preferably, the second distance (23) separates two adjacent groups (6) of the current collector tap (7). The second distance (23) is measured along the X-axis. The second distance (23) changes as it moves along the first electrode (2) and the second electrode (3). This creates a desired pattern as shown in FIG. 2. In practice, it is desirable for the second distance (23) to vary between groups (6) in order to align with the position of a specific group (6) within the cylinder.

[0086] Preferably, the second distance (23) decreases as it moves along the first electrode (2) in the winding direction (19). This creates a desired pattern as shown in FIG. 5. In practice, to fit the position of a specific group (6) within the cylinder, it is preferable that the second distance (23) decreases between groups (6) along the winding direction (19).

[0087] Preferably, according to the embodiment shown in FIG. 2, the current collector tab (7) has an isosceles trapezoidal shape.

[0088] This shape facilitates the bending of the current collector tap (7).

[0089] Preferably, each current collector tap (7) is,

[0090] - A first upper base (24) that aligns with the upper edge (4) of the first electrode (2) and a first lower base (25) that aligns with the lower edge (5) of the second electrode (3),

[0091] - A second upper base (26) corresponding to the upper apex (8) of the first electrode (2) and a second lower base (27) corresponding to the lower apex (10) of the second electrode (3),

[0092] - Includes two upper side edges (32) connecting the first upper base (24) to the second upper base (26) and two lower side edges (33) connecting the first lower base (25) to the second lower base (27).

[0093] Preferably, the first base (24, 25) has a first length (28) measured along the X-axis, and the second base (26, 27) has a second length (29) measured along the X-axis. The second length (29) is shorter than the first length (28).

[0094] Accordingly, an isosceles trapezoidal shape can be obtained.

[0095] Preferably, the ratio of the first length (28) to the second length (29) is 1 to 2. This ratio is calculated by dividing the first length (28) by the second length (29).

[0096] The inventor determined that this range is particularly advantageous in that it facilitates the bending of the current collector tap (7) while preventing the formation of metal clusters.

[0097] Preferably, according to the embodiment illustrated in FIG. 1, the current collector tab (7) is substantially rectangular in shape.

[0098] Preferably, the third length (30) between the groups (6) are different from each other.

[0099] This enables obtaining a desired pattern as shown in Fig. 5, and this pattern corresponds to technical considerations.

[0100] Preferably, the third length (30) decreases as it moves in the winding direction (19).

[0101] Preferably, according to an alternative embodiment illustrated in FIG. 3 and FIG. 4, each current collector tap (7) includes a cut (31) along the Y-axis. The cut (31) separates each current collector tap (7) into two half taps of substantially the same size.

[0102] This makes it easier to bend the current collector tap (7) because bending the half tap is a simpler task.

[0103] Preferably, the incision (31) at the first electrode (2) extends from the upper edge (4) to the upper apex (8). At the second electrode (3), the incision (31) extends from the lower edge (5) to the lower apex (10).

[0104] This prevents metal clusters from forming at the base of the current collector tab (7). It also prevents ripples from forming on the current collector tab (7) when the electrode is wound.

[0105] Preferably, the amount of change in the first distance (22) between groups (6) is substantially the same as the amount of change in the third length (30). In other words, for example, when moving from one group to the next, if the first distance (22) increases by 1 mm, the third length (30) also increases by 1 mm.

[0106] With such first distance (22) and third length (30), the occurrence of poor angle alignment in the same row (20) can be prevented.

Claims

Claim 1 As a battery cell (1) for an electric propulsion vehicle, the cell (1) comprises at least one continuous laminate composed of: - a sheet of a first positive electrode (2) including an upper edge (4); - a sheet of a first insulating separator; - a sheet of a second negative electrode (3) including a lower edge (5); and - a sheet of a second insulating separator. The at least one laminate is wound around itself about a central axis (Y) to form a cylinder. The first positive electrode (2) and the second negative electrode (3) each comprise at least two groups (6) of current collector tabs (7). Each group (6) comprises at least two current collector tabs (7). Each current collector tab (7) extends over a predetermined height (9) measured along the central axis (Y), from the upper edge (4) of the first positive electrode (2) and from the lower edge (5) of the second negative electrode (3) to the upper apex (8) and lower apex (10), respectively. A battery cell (1), wherein the current collector taps (7) within the same group (6) in the cell (1) have substantially the same height (9), the height (9) of the current collector taps (7) differs between groups (6), and in the cell, the current collector taps (7) of a specific group (6) have a third length (30) measured along a first axis (X) that is substantially perpendicular to the central axis (Y) and parallel to the upper edge (4) and the lower edge (5), and in the cell, the first separation distance (22) between two current collector taps of the same group (6) is the same and varies between groups (6), and in the cell, in a specific group (6), the third length (30) is 50% to 150% of the first separation distance (22). Claim 2 A battery cell (1) in which, in a specific group (6), the third length (30) is 80% to 120% of the first separation distance (22). Claim 3 In claim 1, a battery cell (1) in which the first separation distance (22) in a specific group (6) is substantially the same as the third length (30). Claim 4 A battery cell (1) in which the height (9) of the current collector tap (7) decreases as it moves along the first positive electrode (2) and the second negative electrode (3) in the winding direction (19). Claim 5 In claim 1, the cell (1) is wound around itself around a central axis (Y), and the cell (1) comprises a plurality of rows (20) of current collector taps (7), wherein the rows (20) extend from a periphery (14) of the cell (1) toward a center (15) of the cell (1) located on the central axis (Y). Claim 6 In paragraph 5, the height (9) of the current collector tap (7) decreases as it moves from the periphery (14) toward the center (15), in a battery cell (1). Claim 7 A battery cell (1) in any one of claims 1 to 6, wherein the first separation distance (22) decreases between groups (6) as it moves along the first positive electrode (2) and the second negative electrode (3) in the winding direction (19). Claim 8 A battery cell (1) in any one of claims 1 to 6, wherein a second distance (23) separating the current collector taps (7) of two adjacent groups (6), measured along the first axis (X), changes as it moves along the first positive electrode (2) and the second negative electrode (3). Claim 9 In claim 8, the battery cell (1) is reduced as the second distance (23) moves along the first positive electrode (2) and the second negative electrode (3) in the winding direction (19). Claim 10 A battery cell (1) in any one of claims 1 to 6, wherein the current collector tap (7) is an isosceles trapezoidal shape. Claim 11 In claim 10, the current collector tap (7) comprises: - a first upper bottom edge (24) corresponding to the upper edge (4) of the first positive electrode (2) and a first lower bottom edge (25) corresponding to the lower edge (5) of the second negative electrode (3); - a second upper bottom edge (26) corresponding to the upper apex (8) of the current collector tap (7) and a second lower bottom edge (27) corresponding to the lower apex (10) of the current collector tap (7); - two upper side edges (32) connecting the first upper bottom edge (24) to the second upper bottom edge (26) and two lower side edges (33) connecting the first lower bottom edge (25) to the second lower bottom edge (27), the battery cell (1). Claim 12 In claim 11, the first base (24, 25) has a first length (28), and the second base (26, 27) has a second length (29) that is smaller than the first length (28), wherein the first length (28) and the second length (29) are measured along the first axis (X), a battery cell (1). Claim 13 In claim 12, a battery cell (1) in which the ratio of the first length (28) and the second length (29) is 1 to 2. Claim 14 A battery cell (1) in which, in any one of claims 1 to 6, the current collector tap (7) is substantially rectangular in shape. Claim 15 In any one of paragraphs 1 to 6, a battery cell (1) having a third length (30) that is different between groups (6). Claim 16 A battery cell (1) in any one of claims 1 to 6, wherein the third length (30) decreases as it moves in the winding direction (19). Claim 17 A battery cell (1) according to any one of claims 1 to 6, wherein each current collector tap (7) includes a cut (31) along a central axis (Y), and said cut (31) separates each current collector tap (7) into two half-tabs of substantially the same size. Claim 18 In claim 17, the incision (31) at the first positive electrode (2) extends from the upper edge (4) to the upper apex (8), and the incision (31) at the second negative electrode (3) extends from the lower edge (5) to the lower apex (10), in a battery cell (1). Claim 19 A battery cell (1) in any one of claims 1 to 6, wherein the amount of change in the first separation distance (22) between groups (6) is the same as the amount of change in the third length (30).

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