Aluminum shell structure for improving battery cell performance

Abstract

The utility model relates to the technical field of battery cells, in particular to an aluminum shell structure for improving the performance of a battery cell. The aluminum shell body is provided with an upper large surface and a lower large surface, the upper large surface and the lower large surface have a first thickness a at first positions, and the first positions are four corners of the upper large surface and the lower large surface; the upper large surface and the lower large surface have a second thickness b at a second position, and the second position is located on one side edge of the upper large surface and the lower large surface; the upper large surface and the lower large surface have a third thickness c at a third position, and the third position is the other side edge of the upper large surface and the lower large surface; the thickness of the first thickness a is smaller than that of the second thickness b, and the thickness of the first thickness a is smaller than that of the third thickness c. The arc-shaped thickness change gradient is designed at the bottom of the side surface of the aluminum shell, so that the group margin at four corners of the bottom can be improved, and the binding force of the side surfaces and large surfaces at the four corners of the aluminum shell on the expansion of the pole piece is reduced, thereby reducing the lithium precipitation of the battery cell and improving the cycle performance of the battery cell.

Description

Technical Field

[0001] The utility model relates to the technical field of battery cores, in particular to an aluminum shell structure for improving the performance of battery cores. Background Art

[0002] Aluminum shell battery is a high-performance battery with advantages such as high energy density, good safety and long service life. Therefore, it has attracted much attention in the fields of automobiles and electric vehicles. At present, aluminum shell batteries are divided into two processes: lamination and winding. However, the future product planning of global leading battery companies is gradually switching to laminated batteries. This is mainly because after the positive and negative plates and diaphragms of the wound structure battery are wound into batteries, the electrodes on the edges of both sides have a large curvature, which is easy to deform and twist during the charging and discharging process, resulting in a decrease in battery performance and even a safety hazard; on the other hand, due to the uneven current distribution on both sides during the discharge process, the voltage polarization of the wound battery is large, resulting in unstable discharge voltage. Unlike winding, the principle of the lamination process determines that the positive and negative plates and diaphragms of the battery will not bend during the manufacturing process and can be fully unfolded and stacked together. This can not only reduce the internal resistance of the battery and increase the power of the battery, but more importantly, the flat and stable interface allows the pole pieces to shrink and expand synchronously, making the deformation and electric field uniform, making it easier for electrons to move inside the battery, thereby achieving faster charging and discharging speeds. At the same time, at the same volume, the energy density of the laminated battery cell is about 2.5% higher than that of the wound battery cell.

[0003] However, lithium deposition is prone to occur at the two corners at the bottom of the stacked battery cell, especially when the battery cell group margin is formed with the formation of lithium dendrites, which greatly reduces the cycle performance of the battery cell. The main reason is that the aluminum shell used in the current aluminum shell battery cell has the same width from top to bottom, and the bottom and side surfaces of the four corners are thicker than the large surface. During the cycle, as the negative electrode expands, the four corners are more constrained on the electrode sheet, resulting in lithium deposition in the battery cell. Lithium deposition is prone to occur at the two corners at the bottom of the stacked battery cell, and the cycle performance of the battery cell is greatly reduced with the formation of lithium dendrites. The main reason is that the aluminum shell used in the current aluminum shell battery cell has the same width from top to bottom, and the bottom and side surfaces of the four corners are thicker than the large surface. During the cycle, as the negative electrode expands, the four corners are more constrained on the electrode sheet, resulting in lithium deposition in the battery cell. Summary of the invention

[0004] The technical problem to be solved by the utility model is: in order to solve the problems existing in the prior art in the above-mentioned background technology, to provide an aluminum shell structure with a reasonable structure, which improves the cycle performance of the laminated battery core and increases the energy density of the battery.

[0005] The technical solution adopted by the utility model to solve its technical problems is: an aluminum shell structure for improving the performance of a battery cell, comprising an aluminum shell body, wherein the aluminum shell body has an upper large surface and a lower large surface, the upper large surface and the lower large surface have a first thickness a at a first position, and the first position is on the four corners of the upper large surface and the lower large surface; the upper large surface and the lower large surface have a second thickness b at a second position, and the second position is on one side of the upper large surface and the lower large surface; the upper large surface and the lower large surface have a third thickness c at a third position, and the third position is on the other side of the upper large surface and the lower large surface; the thickness of the first thickness a is less than the thickness of the second thickness b, and the thickness of the first thickness a is less than the thickness of the third thickness c.

[0006] Furthermore, the distance between the first thickness a and the second thickness b is 3 to 10 cm; the distance between the first thickness a and the third thickness c is 5 to 20 cm.

[0007] Furthermore, the thickness changes between the first thickness a and the second thickness b, and between the first thickness a and the third thickness c on the upper large surface and the lower large surface are in an arc shape, and the arc is 30° to 45°.

[0008] Furthermore, the thickness at the first thickness a is 0.07 to 0.13 mm smaller than the thickness at the second thickness b; the thickness at the first thickness a is 0.07 to 0.13 mm smaller than the thickness at the third thickness c.

[0009] Furthermore, the upper large surface and the lower large surface both include a first side, a second side, a third side and a fourth side connected in sequence, the first side and the third side are arranged opposite to each other, the second side and the fourth side are arranged opposite to each other, the first side and the second side intersect, and an angle is formed at the intersection of adjacent sides.

[0010] Furthermore, an opening is provided on the aluminum shell body, and a top cover is covered on the opening; the aluminum shell body includes an upper large surface, a lower large surface, and a side surface connecting the upper large surface and the lower large surface, and one side surface is an opening end.

[0011] Furthermore, adjacent surfaces are transitioned through curved surfaces.

[0012] Beneficial effects of the utility model: the bottom of the aluminum shell side is designed with an arc-shaped thickness change gradient, which can improve the group margin at the four corners of the bottom, reduce the restraint force of the sides and large surfaces at the four corners of the aluminum shell on the expansion of the pole piece, thereby reducing lithium plating of the battery cell and improving the cycle performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0014] Figure 1 It is a structural schematic diagram of the utility model;

[0015] Figure 2It is a structural schematic diagram of the utility model in another direction;

[0016] Figure 3 It is a partial enlarged view of the utility model;

[0017] In the figure: 1. aluminum shell body, 2. upper large surface, 3. lower large surface, 4. first side, 5. second side, 6. third side, 7. fourth side, 8. side. DETAILED DESCRIPTION

[0018] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0019] Embodiment 1:

[0020] like Figures 1 to 3 An aluminum shell structure for improving the performance of a battery cell is shown, comprising an aluminum shell body 1, wherein the aluminum shell body 1 has an upper large surface 2 and a lower large surface 3, as shown in FIG. Figure 1 As shown, the upper large surface 2 and the lower large surface 3 both include a first side 4, a second side 5, a third side 6 and a fourth side 7 which are connected in sequence. The first side 4 and the third side 6 are arranged opposite to each other, the second side 5 and the fourth side 7 are arranged opposite to each other, the first side 4 and the second side 5 intersect with each other, and an angle is formed at the intersection of adjacent sides.

[0021] like Figures 1-2 As shown, an opening is provided on the aluminum shell body 1, and a top cover is closed on the opening; the aluminum shell body 1 includes an upper large surface 2, a lower large surface 3, and a side surface 8 connecting the upper large surface 2 and the lower large surface 3, one side surface 8 is an open end, and adjacent surfaces are transitioned by an arc surface.

[0022] Take the large surface 2 above as the reference and take the lower left corner as an example:

[0023] The upper large surface 2 and the lower large surface 3 have a first thickness a at a first position, and the first position is at four corners (the corner is the lower left corner) of the upper large surface 2 and the lower large surface 3;

[0024] The upper large surface 2 and the lower large surface 3 have a second thickness b at a second position, and the second position is on one side (the side is the first side 4) of the upper large surface 2 and the lower large surface 3;

[0025] The upper large surface 2 and the lower large surface 3 have a third thickness c at a third position, and the third position is on the other side edge (the side edge is the fourth side edge 7) of the upper large surface 2 and the lower large surface 3;

[0026] The thickness of the first thickness a is smaller than the thickness of the second thickness b,

[0027] The thickness of the first thickness a is smaller than the thickness of the third thickness c.

[0028] When the distance between the first thickness a and the second thickness b is 10 cm, the thickness at the first thickness a is 0.1 mm thinner than the thickness at the second thickness b;

[0029] When the distance between the first thickness a and the third thickness c is 10 cm, the thickness at the first thickness a is 0.1 mm thinner than the thickness at the third thickness c.

[0030] The thickness changes between the first thickness a and the second thickness b, and between the first thickness a and the third thickness c on the upper large surface 2 and the lower large surface 3 are in an arc shape, and the arc is 30°.

[0031] Embodiment 2:

[0032] The difference from Example 1 is that: when the distance between the first thickness a and the second thickness b is 5 mm, the thickness at the first thickness a is 0.1 mm thinner than the thickness at the second thickness b;

[0033] When the distance between the first thickness a and the third thickness c is 10 mm, the thickness at the first thickness a is 0.1 mm thinner than the thickness at the third thickness c;

[0034] The thickness changes between the first thickness a and the second thickness b, and between the first thickness a and the third thickness c on the upper large surface 2 and the lower large surface 3 are in an arc shape, and the arc is controlled at 30°.

[0035] Embodiment 3:

[0036] The difference from Example 1 is that: when the distance between the first thickness a and the second thickness b is 5 mm, the thickness at the first thickness a is 0.13 mm thinner than the thickness at the second thickness b;

[0037] When the distance between the first thickness a and the third thickness c is 15 mm, the thickness at the first thickness a is 0.13 mm thinner than the thickness at the third thickness c;

[0038] The thickness changes between the first thickness a and the second thickness b, and between the first thickness a and the third thickness c on the upper large surface 2 and the lower large surface 3 are in an arc shape, and the arc is controlled at 35°.

[0039] Embodiment 4: The difference from Embodiment 1 is that: when the distance between the first thickness a and the second thickness b is 10 mm, the thickness at the first thickness a is 0.13 mm thinner than the thickness at the second thickness b;

[0040] When the distance between the first thickness a and the third thickness c is 10 mm, the thickness at the first thickness a is 0.13 mm thinner than the thickness at the third thickness c;

[0041] The thickness changes between the first thickness a and the second thickness b, and between the first thickness a and the third thickness c on the upper large surface 2 and the lower large surface 3 are in an arc shape, and the arc is controlled at 45°.

[0042] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An aluminum shell structure for improving battery performance, characterized in that: The aluminum shell body (1) comprises an upper large surface (2) and a lower large surface (3), wherein the upper large surface (2) and the lower large surface (3) have a first thickness a at a first position, and the first position is at four corners of the upper large surface (2) and the lower large surface (3); The upper large surface (2) and the lower large surface (3) have a second thickness b at a second position, and the second position is on one side of the upper large surface (2) and the lower large surface (3); The upper large surface (2) and the lower large surface (3) have a third thickness c at a third position, and the third position is on the other side of the upper large surface (2) and the lower large surface (3); The thickness of the first thickness a is smaller than the thickness of the second thickness b, The thickness of the first thickness a is smaller than the thickness of the third thickness c.

2. The aluminum shell structure for improving battery core performance according to claim 1, characterized in that: The distance between the first thickness a and the second thickness b is 3 to 10 cm; The distance between the first thickness a and the third thickness c is 5 to 20 cm.

3. The aluminum shell structure for improving battery core performance according to claim 1, characterized in that: The thickness changes between the first thickness a and the second thickness b, and between the first thickness a and the third thickness c on the upper large surface (2) and the lower large surface (3) are in an arc shape, with an arc of 30° to 45°.

4. The aluminum shell structure for improving battery core performance according to claim 1, characterized in that: The thickness at the first thickness a is 0.07 to 0.13 mm smaller than the thickness at the second thickness b; The thickness at the first thickness a is 0.07 to 0.13 mm smaller than the thickness at the third thickness c.

5. The aluminum shell structure for improving battery core performance according to claim 1, characterized in that: The upper large surface (2) and the lower large surface (3) both include a first side edge (4), a second side edge (5), a third side edge (6) and a fourth side edge (7) which are connected in sequence; the first side edge (4) and the third side edge (6) are arranged opposite to each other, the second side edge (5) and the fourth side edge (7) are arranged opposite to each other, the first side edge (4) and the second side edge (5) intersect with each other, and an angle is formed at the intersection of adjacent side edges.

6. The aluminum shell structure for improving battery core performance according to claim 1, characterized in that: The aluminum shell body (1) is provided with an opening, and a top cover is provided on the opening; The aluminum shell body (1) comprises an upper large surface (2), a lower large surface (3), and a side surface (8) connecting the upper large surface (2) and the lower large surface (3), and one side surface (8) is an open end.

7. The aluminum shell structure for improving battery performance according to claim 6, characterized in that: Adjacent surfaces are transitioned through arc surfaces.

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