Battery cell shell and battery cell

Abstract

The utility model provides a battery cell shell and a battery cell, and relates to the technical field of batteries, the battery cell shell comprises a shell body, the shell body comprises at least two shell surfaces and a connecting surface arranged between the adjacent shell surfaces, and an included angle is formed between the adjacent shell surfaces; a first rough layer is arranged on the outer side surface of the outer shell face, and a second rough layer is arranged on the outer side surface of the connecting face. Wherein the roughness R1 of the first rough layer and the roughness R2 of the second rough layer meet the condition that R1 is smaller than R2. According to the embodiment of the invention, the roughness R1 of the first rough layer is smaller than the roughness R2 of the second rough layer, so that the connecting surface has a better adhesion effect on the insulating coating, and the problem that the adhesion effect on the insulating coating is poor due to the bending of the connecting surface is solved; therefore, the shell surface and the connecting surface can be well adhered to the insulating coating, the risk that the insulating coating falls off in a partial region in the battery cell shell is reduced, and the service life of the battery cell shell is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell casing and a battery cell. Background Art

[0002] During the battery production process, an insulating coating is usually applied to the battery casing to improve the non-adhesion and corrosion resistance of the battery cell casing, prevent dust from contaminating the surface of the battery cell casing, and effectively reduce the risk of corrosion and damage to the surface of the battery cell casing.

[0003] In related technologies, the insulating coating is applied directly to the surface of the cell casing. However, the untreated cell casing has insufficient adhesion, which can easily cause the insulating coating to fall off and affect its quality. Furthermore, because different areas of the cell casing have different adhesion properties to the insulating coating, if the surface roughness of the cell casing remains consistent, the insulating coating can easily fall off in areas with poor adhesion during use, causing corrosion and damage to the cell casing, shortening its service life. Utility Model Content

[0004] The embodiments of the present application provide a battery cell casing and a battery cell, which can ensure the adhesion performance between the insulating coating and the battery cell casing and reduce the shedding of the insulating coating.

[0005] In a first aspect, an embodiment of the present application provides a battery cell housing, comprising:

[0006] The shell body includes at least two shell surfaces and a connecting surface arranged between adjacent shell surfaces, and the adjacent shell surfaces are arranged at an angle;

[0007] The outer surface of the outer shell surface is provided with a first rough layer, and the outer surface of the connecting surface is provided with a second rough layer;

[0008] The roughness R1 of the first rough layer and the roughness R2 of the second rough layer satisfy: R1<R2.

[0009] In some embodiments, the roughness R1 of the first rough layer satisfies: 3.2≤Ra≤12.5, 6.3≤Rz≤50;

[0010] And / or, the roughness R2 of the second rough layer satisfies: 6.3≤Ra≤50, 25≤Rz≤100.

[0011] In some embodiments, the thickness of the first rough layer is 50-120 μm;

[0012] And / or, the second rough layer has a thickness of 100-200 μm.

[0013] In some embodiments, the connecting surface is a rounded corner or a chamfered corner.

[0014] In some embodiments, the connecting surface is a rounded corner portion, and the rounded corner portion has a radius of 2 mm to 4 mm.

[0015] In some embodiments, the battery cell housing further comprises an insulating coating;

[0016] The insulating coating is disposed on the first rough layer and the second rough layer.

[0017] In some embodiments, a transition surface is provided on one side of the outer shell surface close to the connection surface;

[0018] The outer surface of the transition surface is provided with a third rough layer, and the roughness R3 of the third rough layer satisfies: R1<R3<R2.

[0019] In some embodiments, the roughness R3 of the third rough layer satisfies: 6.3≤Ra≤12.5, 12.5≤Rz≤50.

[0020] In some embodiments, the transition surface is provided on at least one side of the outer shell surface in the first direction;

[0021] The width of the transition surface along the first direction is W1, and the width of the outer shell surface along the first direction is W2; 0.5%≤W1 / W2≤1%.

[0022] In a second aspect, an embodiment of the present application further provides a battery cell, comprising the battery cell casing as described above.

[0023] Beneficial effects of the embodiments of the present application:

[0024] In an embodiment of the present application, the battery cell casing includes a casing body, the casing body includes a plurality of casing surfaces, and a connecting surface arranged between adjacent casing surfaces, and the adjacent casing surfaces are arranged at an angle. That is, the connecting surface is a curved structure, which can connect the casing surfaces arranged at an angle. Since the connecting surface is a curved structure, the adhesion effect to the insulating coating is poor. By providing a first rough layer and a second rough layer on the outer surfaces of the casing surface and the connecting surface respectively, and the roughness R1 of the first rough layer is less than the roughness R2 of the second rough layer, the connecting surface can have a better adhesion effect to the insulating coating, making up for the problem of poor adhesion to the insulating coating caused by the bending of the connecting surface, so that both the casing surface and the connecting surface can have good adhesion to the insulating coating, reducing the risk of the insulating coating falling off in some areas of the battery cell casing, and extending the service life of the battery cell casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 Schematic diagram of the three-dimensional structure of the battery cell housing provided in an embodiment of the present application;

[0027] Figure 2 yes Figure 1 A magnified schematic diagram of point A in the middle;

[0028] Figure 3 This is a front view of a battery cell housing provided in an embodiment of the present application;

[0029] Figure 4 is a side view of a battery cell housing provided in an embodiment of the present application;

[0030] Figure 5 is a bottom view of a battery cell housing provided in an embodiment of the present application;

[0031] Figure 6 is a top view of a battery cell housing provided in an embodiment of the present application;

[0032] Figure 7 yes Figure 6 A magnified schematic diagram of point B in the middle;

[0033] Figure 8 This is a schematic diagram of the three-dimensional structure of the battery cell housing provided in the embodiment of the present application. Figure 2 ;

[0034] Figure 9 yes Figure 8 The enlarged schematic diagram of point C in the middle;

[0035] Figure 10 This is a schematic diagram of the three-dimensional structure of the battery cell housing provided in the embodiment of the present application. Figure 3 ;

[0036] Figure 11 yes Figure 10 The enlarged schematic diagram of point D in the middle;

[0037] Figure 12 Schematic diagram of the explosion structure of the battery provided in the embodiment of the present application.

[0038] Description of reference numerals:

[0039] 100. Battery cell casing; 1. Casing body; 11. Casing surface; 111. First side surface; 112. Second side surface; 113. Bottom surface; 12. Connection surface; 13. Transition surface; 21. First rough layer; 22. Second rough layer; 23. Third rough layer; 3. Insulation coating; 200. Battery cell; 210. Cover plate. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; and "inside" and "outside" refer to the outline of the device.

[0041] First, as Figure 1 and Figure 2 As shown, an embodiment of the present application provides a battery cell housing 100, comprising a housing body 1, wherein the housing body 1 comprises at least two housing surfaces 11 and a connecting surface 12 disposed between adjacent housing surfaces 11, with adjacent housing surfaces 11 disposed at an angle. A first rough layer 21 is disposed on the outer surface of the housing surface 11, and a second rough layer 22 is disposed on the outer surface of the connecting surface 12. The roughness R1 of the first rough layer 21 and the roughness R2 of the second rough layer 22 satisfy the following relationship: R1 < R2.

[0042] In the related art, the cell casing 100 is typically subjected to a uniform surface treatment, and then an insulating coating 3 is applied to the surface-treated cell casing 100. However, due to differences in the adhesion of the insulating coating 3 to different areas of the cell casing 100, the insulating coating 3 can easily fall off in some areas during use, leading to corrosion of the cell casing 100. Specifically, due to the curvature of the connecting surface 12 between adjacent casing surfaces 11 of the cell casing 100, the insulating coating 3 has poor adhesion and is more likely to fall off than other areas.

[0043] In the battery cell casing provided in the embodiment of the present application, the outer surfaces of the outer shell surface 11 and the connecting surface 12 are respectively provided with a first rough layer 21 and a second rough layer 22, and there is a difference between the roughness R1 of the first rough layer 21 and the roughness R2 of the second rough layer 22, that is, R1 < R2, which can enable the connecting surface 12 to have a better adhesion effect on the insulating coating 3, compensate for the problem of poor adhesion to the insulating coating 3 due to the bending of the connecting surface 12, so that the insulating coating 3 can achieve good adhesion with both the outer shell surface 11 and the connecting surface 12, reducing or avoiding the problem of the insulating coating 3 falling off due to the poor adhesion of the connecting surface 12 during use.

[0044] Specifically, since the connection surface 12 is curved, etc., the effect of its surface adhesion to the insulating coating 3 is affected. By setting its roughness to be greater, its adhesion to the insulating coating 3 can be improved. Since the outer shell surface 11 has a relatively flat surface, its adhesion to the insulating coating 3 is better than that of the connection surface 12, and its roughness can be lowered to reduce preprocessing time and save costs.

[0045] The battery cell housing 100 is usually open on one side to facilitate the installation of the battery cell. After the battery cell is installed, a cover is placed on the opening to form a closed accommodating cavity. The battery cell housing 100 can be cylindrical or rectangular. When the battery cell housing 100 is cylindrical, one of the circular surfaces of the cylinder is open, and its outer shell surface 11 includes a cylindrical surface and a circular surface, and a connecting surface 12 is provided between the cylindrical surface and the circular surface. Among them, a first rough layer 21 is provided on the outer surface of the cylindrical surface and the circular surface, and a second rough layer 22 is provided on the outer surface of the connecting surface 12. By setting the roughness of the first rough layer 21 and the second rough layer 22 to be different, the insulating coating 3 can have good adhesion everywhere in the battery cell housing 100.

[0046] When the cell housing 100 is a rectangular parallelepiped, Figure 1-Figure 5 As shown, one surface of the cell casing 100 is open, and its casing surface 11 includes two opposing first side surfaces 111, two second side surfaces 112, and a bottom surface 113. A connecting surface 12 is provided between each two adjacent surfaces. The outer surfaces of the two first side surfaces 111, the two second side surfaces 112, and the bottom surface 113 are all provided with a first roughened layer 21, and the outer surface of the connecting surface 12 is provided with a second roughened layer 22. By providing different roughness levels for the first roughened layer 21 and the second roughened layer 22, the insulating coating 3 can be effectively adhered to all parts of the cell casing 100.

[0047] The first rough layer 21 and the second rough layer 22 can be formed by various methods such as sandblasting, sandpaper polishing and laser cleaning.

[0048] For example, the housing body 1 can be surface treated by sandblasting to form the first rough layer 21 and the second rough layer 22. The sandblasting material can be selected from quartz sand, silica sand, steel balls, garnet sand, aluminum oxide, or steel shot. To form the first rough layer 21 and the second rough layer 22 with different roughness on the outer surfaces of the housing surface 11 and the connecting surface 12, sandblasting materials of different sizes can be used, and different sandblasting speeds can be set.

[0049] In some embodiments, the roughness R1 of the first rough layer 21 satisfies: 3.2≤Ra≤12.5, 6.3≤Rz≤50.

[0050] When the roughness of the first rough layer 21 is too low, its adhesion to the insulating coating 3 is poor, reducing the bonding area between the insulating coating 3 and the first rough layer 21 and making the insulating coating 3 more susceptible to detachment. However, when the roughness of the first rough layer 21 is too high, the excessive presence of protrusions and depressions reduces the number of contact points between the insulating coating 3 and the first rough layer 21. Furthermore, the material in the insulating coating 3 cannot fully penetrate the gaps in the first rough layer 21, thus reducing adhesion. However, ensuring that the roughness R1 of the first rough layer 21 satisfies the following conditions: 3.2 ≤ Ra ≤ 12.5, 6.3 ≤ Rz ≤ 50 can improve the adhesion of the first rough layer 21 to the insulating coating 3, allowing the material in the insulating coating 3 to better fill the tiny gaps on the surface of the first rough layer 21, resulting in a better bonding effect.

[0051] For example, when sandblasting is used to form the first rough layer 21, the particle size of the sandblasting material can be set to 10 μm-300 μm, and the sandblasting speed can be set to 10 m / s. 3 / h-100m 3 / h, the distance between the sandblasting nozzle and the shell surface is 0.25-2cm, and the number of sandblasting times can be set to more than twice.

[0052] It should be noted that Ra and Rz both represent roughness, where Ra represents the arithmetic mean of the absolute values of the profile deviations within the sampling length, and Rz represents the sum of the average of the five largest profile peak heights and the average of the five largest profile valley depths within the sampling length.

[0053] In some embodiments, the roughness R2 of the second rough layer 22 satisfies: 6.3≤Ra≤50, 25≤Rz≤100.

[0054] Similar to the first rough layer 21, the second rough layer 22 is also susceptible to similar problems when its roughness is too low or too high. Furthermore, the roughness of the second rough layer 22 is greater than that of the first rough layer 21. This maintains the roughness of the second rough layer 22 within an appropriate range while providing better adhesion to the first rough layer 21, compensating for the poor adhesion of the insulating coating 3 due to the curvature of the connecting surface 12. Therefore, the roughness R2 of the second rough layer 22 satisfies the following conditions: 6.3 ≤ Ra ≤ 50, 25 ≤ Rz ≤ 100.

[0055] For example, when sandblasting is used to form the second rough layer 22, the particle size of the sandblasting material can be set to 5 μm-100 μm, and the sandblasting speed can be set to 8 m / s. 3 / h-80m 3 / h, the distance between the sandblasting nozzle and the shell surface is 0.25-2cm, and the number of sandblasting times can be set to more than twice.

[0056] In some embodiments, the thickness of the first rough layer 21 is 50-120 μm. A thicker first rough layer 21 increases its roughness, which increases the contact area with the insulating coating 3 and improves adhesion. A thinner first rough layer 21 decreases its roughness and reduces adhesion. However, if the first rough layer 21 is too thick, it can affect the strength of the housing body 1, and the insulating coating 3 material can have difficulty entering the tiny gaps in the first rough layer 21 and achieving a tight bond. Therefore, the thickness of the first rough layer 21 is set to 50-120 μm.

[0057] In some embodiments, the thickness of the second rough layer 22 is 100-200 μm. Similarly, the thicker the second rough layer 22, the greater its roughness, which can increase the contact area with the insulating coating 3 and thus improve adhesion. However, the thinner the second rough layer 22, the smaller its roughness, and the poorer adhesion. However, if the thickness of the second rough layer 22 is too large, it will easily affect the strength of the housing body 1, and the material of the insulating coating 3 will not easily enter the tiny gaps in the second rough layer 22 and achieve a tight bond with it. Because the second rough layer 22 is disposed on the connection surface 12, relative to the housing surface 11, due to its curved structure, its adhesion to the insulating coating 3 is poor. A larger thickness can improve adhesion while ensuring an appropriate thickness range. Therefore, the thickness of the second rough layer 22 is set to 100-200 μm.

[0058] like Figure 6 and Figure 7As shown, the thickness of the first rough layer 21 is D1, and the thickness of the second rough layer is D2. By reasonably setting the thickness of the two, the adhesion effect of the first rough layer 21 and the second rough layer 22 to the insulating coating 3 can be ensured, while also avoiding the deterioration of the strength of the shell body 1 due to the excessive thickness of the first rough layer 21 and the second rough layer 22.

[0059] For example, if the shell body 1 is surface treated by sandblasting, the thickness of the first rough layer 21 and the second rough layer 22 can be controlled by adjusting the sandblasting process parameters, such as the particle size of the sandblasting material, the number of sandblasting times, etc.

[0060] In some embodiments, the connection surface 12 is a rounded or chamfered portion. By configuring the connection surface 12 as a rounded or chamfered portion, adjacent outer shell surfaces 11 can be connected while enhancing the structural strength of the battery cell housing 100. The rounded or chamfered portions also increase the transition area between adjacent outer shell surfaces 11, facilitating the formation of a second roughness layer 22 with varying degrees of roughness on the rounded or chamfered portions. The rounded or chamfered portions also disperse stress and reduce stress concentration, thereby lowering the risk of damage to the battery cell housing 100.

[0061] In some embodiments, as Figure 6 and Figure 7 As shown, the connecting surface 12 is a rounded corner portion with a radius of 2mm-4mm. Compared with the chamfered portion, the rounded corner portion provides a smoother transition when connecting to the adjacent outer shell surface 11, reducing sharp edges. Therefore, the first rough layer 21 and the second rough layer 22 can smoothly transition, reducing the stress concentration problem caused by the sharp edge transition and reducing the problem of cracking or shedding of the insulating coating 3 at the sharp edge.

[0062] By setting the fillet radius of the fillet to 2mm-4mm, the area of the fillet can be guaranteed, which facilitates the formation of the second rough layer 22, while ensuring that the adjacent shell surfaces 11 can have a smooth transition, reducing or avoiding the appearance of sharp corners, and reducing the risk of cracking or falling off of the insulating coating at the sharp corners.

[0063] For example, Figure 7 As shown in the figure, R is the fillet radius of the fillet.

[0064] In some embodiments, as Figure 8 and Figure 9As shown, the battery cell housing 100 further includes an insulating coating 3, which is disposed on the surfaces of the first rough layer 21 and the second rough layer 22. The insulating coating 3 is disposed on the first rough layer 21 and the second rough layer 22. The first rough layer 21 and the second rough layer 22 can improve the adhesion of the insulating coating 3 to the housing body 1. Moreover, due to the different roughness of the first rough layer 21 and the second rough layer 22, the problem of different adhesion between the housing surface 11 and the connection surface 12 due to structural differences is compensated. As a result, the insulating coating 3 has substantially consistent adhesion on the first rough layer 21 and the second rough layer 22, avoiding cracking or falling off caused by different adhesion in different areas.

[0065] For example, Figure 8 and Figure 9 As shown, the insulating coating 3 is located on the surface of the battery cell housing 100. The housing body 1, the first rough layer 21, the second rough layer 22, and the insulating coating 3 are arranged in order from the inside out. The first and second rough layers 21, 22 are disposed on the housing body 1 and stably bonded to the housing body 1. The surfaces of the first and second rough layers 21, 22 form a plurality of tiny gaps, creating a microstructure with raised and recessed areas. The insulating coating 3 is disposed on the surfaces of the first and second rough layers 21, 22. The material particles in the insulating coating 3 can embed into the tiny gaps between the first and second rough layers 21, 22, making full contact with the microstructure. This enhances the bonding strength between the insulating coating 3 and the first and second rough layers 21, 22, allowing for stable adhesion to the surfaces of the first and second rough layers 21, 22.

[0066] In other embodiments of the present application, Figure 10 and Figure 11 As shown, a transition surface 13 is provided on the side of the outer shell surface 11 close to the connection surface 12. The outer surface of the transition surface 13 is provided with a third rough layer 23, and the roughness R3 of the third rough layer 23 satisfies: R1 < R3 < R2.

[0067] That is, there is a transition surface 13 on the outer shell surface 11, the transition surface 13 is arranged close to the connecting surface 12, and the outer surface of the transition surface 13 is provided with a third rough layer 23, and the roughness of the third rough layer 23 is greater than the roughness of the first rough layer 21, but less than the roughness of the second rough layer 22.

[0068] It is understood that the first rough layer 21, the third rough layer 23, and the second rough layer 22 are sequentially connected in the region formed by the adjacent outer shell surface 11 and the connection surface 12. The third rough layer 23 can reduce the stress concentration at the contact point of the first rough layer 21 and the second rough layer 22 caused by the large difference in roughness between the first rough layer 21 and the second rough layer 22, which can cause the insulating coating 3 to crack or fall off at the contact point of the first rough layer 21 and the second rough layer 22.

[0069] By providing the third rough layer 23 on the transition surface 13 , the stress concentration problem caused by the difference in roughness can be dispersed, thereby improving the adhesion effect.

[0070] In some embodiments, the roughness R3 of the third rough layer 23 satisfies: 6.3≤Ra≤12.5, 12.5≤Rz≤50.

[0071] It is understood that the third rough layer 23 is disposed between the first rough layer 21 and the second rough layer 22 and is used to achieve a transition from the second rough layer 22 having a higher roughness to the first rough layer 21 having a lower roughness. By ensuring that the roughness R3 of the third rough layer 23 satisfies the following conditions: 6.3 ≤ Ra ≤ 12.5, 12.5 ≤ Rz ≤ 50, a good transition can be achieved and good adhesion of the third rough layer 23 to the insulating coating 3 can be ensured.

[0072] In some embodiments, as Figure 10 and Figure 11 The transition surface 13 is provided on at least one side of the outer shell surface 11 in the first direction X. The width of the transition surface 13 along the first direction X is W1, and the width of the outer shell surface along the first direction is W2; 0.5% ≤ W1 / W2 ≤ 1%. If the transition surface 13 is too narrow, the stress concentration caused by the difference in roughness cannot be effectively alleviated. If the transition surface 13 is too wide, it will encroach on the outer shell surface 11, affecting the adhesion of the insulating coating 3 on the outer shell surface 11.

[0073] It is understood that when the transition surface 13 is provided on the outer shell surface 11 and has the third rough layer 23, the insulating coating 3 is also provided on the surfaces of the first rough layer 21, the second rough layer 22, and the third rough layer 23. Because the third rough layer 23 provides a transition between the first rough layer 21 and the second rough layer 22, the problem of cracking and shedding of the insulating coating 3 caused by excessive roughness in adjacent areas is reduced.

[0074] In a second aspect, an embodiment of the present application further provides a battery cell 200 , comprising the battery cell housing 100 as described above.

[0075] like Figure 12 As shown, the battery cell 200 includes a battery cell housing 100 , a cover plate 210 and a battery cell (not shown in the figure). The cover plate 210 can be covered at the opening of the battery cell housing 100 to form an accommodating cavity for accommodating the battery cell.

[0076] The battery cell provided in the embodiment of the present application adopts the above-mentioned battery cell housing 100, which can reduce the risk of the insulating coating 3 falling off, ensure the protective effect of the insulating coating 3, reduce the impact of external corrosion, and thus extend the service life of the battery cell 200.

[0077] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A battery cell casing, characterized in that: include: A shell body, the shell body comprising at least two shell surfaces and a connecting surface arranged between adjacent shell surfaces, wherein the adjacent shell surfaces are arranged at an angle; The outer surface of the outer shell surface is provided with a first rough layer, and the outer surface of the connecting surface is provided with a second rough layer; The roughness R1 of the first rough layer and the roughness R2 of the second rough layer satisfy: R1<R2.

2. The battery cell casing according to claim 1, wherein: The roughness R1 of the first rough layer satisfies: 3.2≤Ra≤12.5, 6.3≤Rz≤50; And / or, the roughness R2 of the second rough layer satisfies: 6.3≤Ra≤50, 25≤Rz≤100.

3. The battery cell casing according to claim 2, wherein: The thickness of the first rough layer is 50-120 μm; And / or, the thickness of the second rough layer is 100-200 μm.

4. The battery cell casing according to claim 1, wherein: The connecting surface is a rounded corner portion or a chamfered corner portion.

5. The battery cell casing according to claim 4, characterized in that: The connecting surface is a rounded corner portion, and the rounded corner radius of the rounded corner portion is 2mm-4mm.

6. The battery cell casing according to any one of claims 1 to 5, characterized in that: Also includes insulating coating; The insulating coating is arranged on the surfaces of the first rough layer and the second rough layer.

7. The battery cell casing according to claim 1, wherein: A transition surface is provided on one side of the outer shell surface close to the connecting surface; A third rough layer is provided on the outer surface of the transition surface, and the roughness R3 of the third rough layer satisfies: R1<R3<R2.

8. The battery cell casing according to claim 7, characterized in that: The roughness R3 of the third rough layer satisfies the following: 6.3≤Ra≤12.5, 12.5≤Rz≤50.

9. The battery cell casing according to claim 7, characterized in that: The transition surface is provided on at least one side of the outer shell surface in the first direction; The width of the transition surface along the first direction is W1, and the width of the outer shell surface along the first direction is W2; 0.5%≤W1 / W2≤1%.

10. A battery cell, characterized in that: The invention comprises a battery cell casing according to any one of claims 1 to 9.

Images